Management of cancer
Encyclopedia
Cancer
can be treated by surgery
, chemotherapy
, radiation therapy
, immunotherapy
, monoclonal antibody therapy
or other methods. The choice of therapy depends upon the location and grade of the tumor and the stage
of the disease, as well as the general state of the patient (performance status
). A number of experimental cancer treatment
s are also under development.
Complete removal of the cancer without damage to the rest of the body is the goal of treatment. Sometimes this can be accomplished by surgery, but the propensity of cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effectiveness. The effectiveness of chemotherapy is often limited by toxicity to other tissues in the body. Radiation can also cause damage to normal tissue.
Because "cancer" refers to a class of diseases,
it is unlikely that there will ever be a single "cure for cancer" any more than there will be a single treatment for all infectious disease
s.
Angiogenesis inhibitors were once thought to have potential as a "silver bullet
" treatment applicable to many types of cancer, but this has not been the case in practice.
, but this is not always possible. When the cancer has metastasized
to other sites in the body prior to surgery, complete surgical excision is usually impossible. In the Halsted
ian model of cancer progression, tumors grow locally, then spread to the lymph nodes, then to the rest of the body. This has given rise to the popularity of local-only treatments such as surgery for small cancers. Even small localized tumors are increasingly recognized as possessing metastatic potential.
Examples of surgical procedures for cancer include mastectomy
for breast cancer, prostatectomy
for prostate cancer, and lung cancer surgery
for non-small cell lung cancer. The goal of the surgery can be either the removal of only the tumor, or the entire organ. A single cancer cell is invisible to the naked eye but can regrow into a new tumor, a process called recurrence. For this reason, the pathologist
will examine the surgical specimen to determine if a margin of healthy tissue is present, thus decreasing the chance that microscopic cancer cells are left in the patient.
In addition to removal of the primary tumor, surgery is often necessary for staging
, e.g. determining the extent of the disease and whether it has metastasized
to regional lymph node
s. Staging is a major determinant of prognosis
and of the need for adjuvant therapy.
Occasionally, surgery is necessary to control symptoms, such as spinal cord compression
or bowel obstruction
. This is referred to as palliative treatment.
If surgery is possible and appropriate, it is commonly performed before other forms of treatment, although the order does not affect the outcome. In some instances, surgery must be delayed until other treatments are able to shrink the tumor.
(also called radiotherapy, X-ray therapy, or irradiation) is the use of ionizing radiation to kill cancer cells and shrink tumors. Radiation therapy can be administered externally via external beam radiotherapy
(EBRT) or internally via brachytherapy
. The effects of radiation therapy are localised and confined to the region being treated. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. Hence, it is given in many fractions, allowing healthy tissue to recover between fractions.
Radiation therapy may be used to treat almost every type of solid tumor, including cancers of the brain, breast, cervix, larynx, lung, pancreas, prostate, skin, stomach, uterus, or soft tissue sarcomas. Radiation is also used to treat leukemia and lymphoma. Radiation dose to each site depends on a number of factors, including the radiosensitivity of each cancer type and whether there are tissues and organs nearby that may be damaged by radiation. Thus, as with every form of treatment, radiation therapy is not without its side effects.
is the treatment of cancer with drugs
("anticancer drugs") that can destroy cancer cells. In current usage, the term "chemotherapy" usually refers to cytotoxic drugs which affect rapidly dividing cells in general, in contrast with targeted therapy (see below). Chemotherapy drugs interfere with cell division in various possible ways, e.g. with the duplication of DNA
or the separation of newly formed chromosome
s. Most forms of chemotherapy target all rapidly dividing cells and are not specific to cancer cells, although some degree of specificity may come from the inability of many cancer cells to repair DNA damage, while normal cells generally can. Hence, chemotherapy has the potential to harm healthy tissue, especially those tissues that have a high replacement rate (e.g. intestinal lining). These cells usually repair themselves after chemotherapy.
Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called "combination chemotherapy"; most chemotherapy regimens are given in a combination.
The treatment of some leukaemias and lymphoma
s requires the use of high-dose chemotherapy, and total body irradiation
(TBI). This treatment ablates the bone marrow, and hence the body's ability to recover and repopulate the blood. For this reason, bone marrow, or peripheral blood stem cell harvesting is carried out before the ablative part of the therapy, to enable "rescue" after the treatment has been given. This is known as autologous stem cell transplantation. Alternatively, hematopoietic stem cells may be transplanted from a matched unrelated donor (MUD).
targeted therapy drugs are generally inhibitors of enzymatic
domains on mutated, overexpressed, or otherwise critical proteins within the cancer cell. Prominent examples are the tyrosine kinase inhibitors imatinib
(Gleevec/Glivec) and gefitinib
(Iressa).
Monoclonal antibody therapy
is another strategy in which the therapeutic agent is an antibody
which specifically binds to a protein on the surface of the cancer cells. Examples include the anti-HER2/neu
antibody trastuzumab
(Herceptin) used in breast cancer, and the anti-CD20 antibody rituximab
, used in a variety of B-cell malignancies.
Targeted therapy
can also involve small peptide
s as "homing devices" which can bind to cell surface receptors or affected extracellular matrix
surrounding the tumor. Radionuclides which are attached to these peptides (e.g. RGDs) eventually kill the cancer cell if the nuclide decays in the vicinity of the cell. Especially oligo- or multimers of these binding motifs are of great interest, since this can lead to enhanced tumor specificity and avidity.
Photodynamic therapy
(PDT) is a ternary treatment for cancer involving a photosensitizer, tissue oxygen, and light (often using lasers). PDT can be used as treatment for basal cell carcinoma
(BCC) or lung cancer
; PDT can also be useful in removing traces of malignant tissue after surgical removal of large tumors.
Cancer immunotherapy refers to a diverse set of therapeutic strategies designed to induce the patient's own immune system
to fight the tumor. Contemporary methods for generating an immune response against tumours include intravesical BCG
immunotherapy for superficial bladder cancer, and use of interferon
s and other cytokine
s to induce an immune response in renal cell carcinoma
and melanoma
patients. Vaccine
s to generate specific immune responses are the subject of intensive research for a number of tumours, notably malignant melanoma and renal cell carcinoma
. Sipuleucel-T
is a vaccine-like strategy in late clinical trials for prostate cancer
in which dendritic cell
s from the patient are loaded with prostatic acid phosphatase
peptides to induce a specific immune response against prostate-derived cells.
Allogeneic hematopoietic stem cell transplantation ("bone marrow transplantation" from a genetically non-identical donor) can be considered a form of immunotherapy, since the donor's immune cells will often attack the tumor in a phenomenon known as graft-versus-tumor effect. For this reason, allogeneic HSCT leads to a higher cure rate than autologous transplantation for several cancer types, although the side effects are also more severe.
The cell based immunotherapy in which the patients own Natural Killer cells(NK) and Cytotoxic T-Lymphocytes(CTL) are used has been in practice in Japan since 1990. NK cells and CTLs primarily kill the cancer cells when they are developed. This treatment is given together with the other modes of treatment such as Surgery, radiotherapy or Chemotherapy and called as Autologous Immune Enhancement Therapy (AIET)
or testosterone
is often an important additional treatment. In certain cancers, administration of hormone agonists, such as progestogens may be therapeutically beneficial.
) that tumors require to survive. Some, such as bevacizumab
, have been approved and are in clinical use. One of the main problems with anti-angiogenesis drugs is that many factors stimulate blood vessel growth in cells normal or cancerous. Anti-angiogenesis drugs only target one factor, so the other factors continue to stimulate blood vessel growth. Other problems include route of administration
, maintenance of stability and activity and targeting at the tumor vasculature.
of cancer patients, and plays an important role in the decision whether the patient is able to undergo other treatments. Although doctors generally have the therapeutic skills to reduce pain, Chemotherapy-induced nausea and vomiting
, diarrhea, hemorrhage and other common problems in cancer patients, the multidisciplinary specialty of palliative care
has arisen specifically in response to the symptom control needs of this group of patients.
Pain medication, such as morphine
and oxycodone
, and antiemetic
s, drugs to suppress nausea and vomiting, are very commonly used in patients with cancer-related symptoms. Improved antiemetics such as ondansetron
and analogues, as well as aprepitant
have made aggressive treatments much more feasible in cancer patients.
Cancer pain
can be associated with continuing tissue damage due to the disease process or the treatment (i.e. surgery, radiation, chemotherapy). Although there is always a role for environmental factors and affective disturbances in the genesis of pain behaviors, these are not usually the predominant etiologic factors in patients with cancer pain. Some patients with severe pain associated with cancer are nearing the end of their lives, but in all cases palliative therapies should be used to control the pain. Issues such as social stigma of using opioids, work and functional status, and health care consumption can be concerns and may need to be addressed in order for the person to feel comfortable taking the medications required to control his or her symptoms. The typical strategy for cancer pain management is to get the patient as comfortable as possible using the least amount of medications possible but opioids, surgery, and physical measures are often required. In the past doctors have been reluctant to prescribe narcotics for pain in terminal cancer patients, for fear of contributing to addiction or suppressing respiratory function. The palliative care
movement, a more recent offshoot of the hospice
movement, has engendered more widespread support for preemptive pain treatment for cancer patients. The World Health Organization
also noted uncontrolled cancer pain as a worldwide problem and established a "ladder" as a guideline for how practitioners should treat pain in patients who have cancer
Cancer-related fatigue
is a very common problem for cancer patients, and has only recently become important enough for oncologists to suggest treatment, even though it plays a significant role in many patients' quality of life.
is a group that provides care at the home of a person that has an advanced illness with a likely prognosis of less than 6 months. As most treatments for cancer involve significant unpleasant side effects, a patient with little realistic hope of a cure or prolonged life may choose to seek comfort care only, forgoing more radical therapies in exchange for a prolonged period of normal living. This is an especially important aspect of care for those patients whose disease is not a good candidate for other forms of treatment. In these patients, the risks related to the chemotherapy
may actually be higher than the chance of responding to the treatment, making further attempts to cure the disease impossible. Of note, patients on hospice can sometimes still get treatments such as radiation
therpy if it is being used to treat symptoms, not as an attempt to cure the cancer.
s, also called research studies, test new treatments in people with cancer. The goal of this research is to find better ways to treat cancer and help cancer patients. Clinical trials test many types of treatment such as new drugs, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy
.
A clinical trial is one of the final stages of a long and careful cancer research process. The search for new treatments begins in the laboratory, where scientists first develop and test new ideas. If an approach seems promising, the next step may be testing a treatment in animals to see how it affects cancer in a living being and whether it has harmful effects. Of course, treatments that work well in the lab or in animals do not always work well in people. Studies are done with cancer patients to find out whether promising treatments are safe and effective.
Patients who take part may be helped personally by the treatment they receive. They get up-to-date care from cancer experts, and they receive either a new treatment being tested or the best available standard treatment for their cancer. At the same time, new treatments also may have unknown risks, but if a new treatment proves effective or more effective than standard treatment, study patients who receive it may be among the first to benefit. There is no guarantee that a new treatment being tested or a standard treatment will produce good results. In children with cancer, a survey of trials found that those enrolled in trials were on average not more likely to do better or worse than those on standard treatment; this confirms that success or failure of an experimental treatment cannot be predicted.
are lipid-covered microvesicles shed by solid tumors into bodily fluids, such as blood and urine. Current research is being done attempting to use exosomes as a detection and monitoring method for a variety of cancers., The hope is to be able to detect cancer with a high sensitivity and specificity via detection of specific exosomes in the blood or urine. The same process can be used to more accurately monitor a patients treatment progress as well. Enzyme linked lectin specific assay or ELLSA has been proven to directly detect melanoma derived exosomes from fluid samples. Previously, exosomes had been measured by total protein content in purified samples and by indirect immunomodulatory effects. ELLSA directly measures exosome particles in complex solutions, and has already been found capable of detecting exosomes from other sources, including ovarian cancer and tuberculosis-infected macrophages.
Exosomes secreted by tumors are also believed to be responsible for triggering programmed cell death (apoptosis) of immune cells; interrupting T-cell signaling required to mount an immune response; inhibiting the production of anti-cancer cytokines, and has implications in the spread of metastasis and allowing for angiogenesis. Studies are currently being done with Lectin Affinity Plasmapheresis (LAP), LAP is a blood filtration method which selectively targets the tumor based exosomes and removes them from the bloodstream. It is believed that decreasing the tumor secreted exosomes in a patients bloodstream will slow down progression of the cancer while at the same time increase the patients own immune response.
(CAM) treatments are the diverse group of medical and health care systems, practices, and products that are not part of conventional medicine and have not been shown to be effective. "Complementary medicine" refers to methods and substances used along with conventional medicine, while "alternative medicine" refers to compounds used instead of conventional medicine. CAM use is common among people with cancer; a 2000 study found that 69% of cancer patients had used at least one CAM therapy as part of their cancer treatment. Most complementary and alternative medicines for cancer have not been rigorously studied or tested. Some alternative treatments which have been investigated and shown to be ineffective continue to be marketed and promoted.
has risen due to the increasing age of pregnant mothers and due to the incidental discovery of maternal tumors during prenatal ultrasound examinations.
Cancer treatment needs to be selected to do least harm to both the woman and her embryo/fetus. In some cases a therapeutic abortion
may be recommended.
Radiation therapy is generally out of the question, and chemotherapy always poses the risk of miscarriage and congenital malformations. Little is known about the effects of medications on the child.
Even if a drug has been tested as not crossing the placenta to reach the child, some cancer forms can harm the placenta and make the drug pass over it anyway. Some forms of skin cancer may even metastasize to the child's body.
Diagnosis is also made more difficult, since computed tomography
is infeasible because of its high radiation dose. Still, magnetic resonance imaging
works normally. However, contrast media
cannot be used, since they cross the placenta.
As a consequence of the difficulties to properly diagnose and treat cancer during pregnancy, the alternative methods are either to perform a Cesarean section when the child is viable in order to begin a more aggressive cancer treatment, or, if the cancer is malignant enough that the mother is unlikely to be able to wait that long, to perform an abortion in order to treat the cancer.
is the most common type of fetal tumor, and usually is benign.
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
can be treated by surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
, radiation therapy
Radiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
, immunotherapy
Immunotherapy
Immunotherapy is a medical term defined as the "treatment of disease by inducing, enhancing, or suppressing an immune response". Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies. While immunotherapies that reduce or suppress are...
, monoclonal antibody therapy
Monoclonal antibody therapy
Monoclonal antibody therapy is the use of monoclonal antibodies to specifically bind to target cells or proteins. This may then stimulate the patient's immune system to attack those cells...
or other methods. The choice of therapy depends upon the location and grade of the tumor and the stage
Cancer staging
The stage of a cancer is a description of the extent the cancer has spread. The stage often takes into account the size of a tumor, how deeply it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to , and whether it has spread to distant organs...
of the disease, as well as the general state of the patient (performance status
Performance status
In medicine , performance status is an attempt to quantify cancer patients' general well-being and activities of daily life. This measure is used to determine whether they can receive chemotherapy, whether dose adjustment is necessary, and as a measure for the required intensity of palliative care...
). A number of experimental cancer treatment
Experimental cancer treatment
Experimental cancer treatments are medical therapies intended or claimed to treat cancer by improving on, supplementing or replacing conventional methods ....
s are also under development.
Complete removal of the cancer without damage to the rest of the body is the goal of treatment. Sometimes this can be accomplished by surgery, but the propensity of cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effectiveness. The effectiveness of chemotherapy is often limited by toxicity to other tissues in the body. Radiation can also cause damage to normal tissue.
Because "cancer" refers to a class of diseases,
it is unlikely that there will ever be a single "cure for cancer" any more than there will be a single treatment for all infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
s.
Angiogenesis inhibitors were once thought to have potential as a "silver bullet
Silver bullet
In folklore, the silver bullet is supposed to be the only kind of bullet for firearms that is effective against a werewolf, witch, or other monsters...
" treatment applicable to many types of cancer, but this has not been the case in practice.
Surgery
In theory, non-hematological cancers can be cured if entirely removed by surgerySurgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, but this is not always possible. When the cancer has metastasized
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
to other sites in the body prior to surgery, complete surgical excision is usually impossible. In the Halsted
William Stewart Halsted
William Stewart Halsted was an American surgeon who emphasized strict aseptic technique during surgical procedures, was an early champion of newly discovered anesthetics, and introduced several new operations, including the radical mastectomy for breast cancer...
ian model of cancer progression, tumors grow locally, then spread to the lymph nodes, then to the rest of the body. This has given rise to the popularity of local-only treatments such as surgery for small cancers. Even small localized tumors are increasingly recognized as possessing metastatic potential.
Examples of surgical procedures for cancer include mastectomy
Mastectomy
Mastectomy is the medical term for the surgical removal of one or both breasts, partially or completely. Mastectomy is usually done to treat breast cancer; in some cases, women and some men believed to be at high risk of breast cancer have the operation prophylactically, that is, to prevent cancer...
for breast cancer, prostatectomy
Prostatectomy
A prostatectomy is the surgical removal of all or part of the prostate gland. Abnormalities of the prostate, such as a tumour, or if the gland itself becomes enlarged for any reason, can restrict the normal flow of urine along the urethra....
for prostate cancer, and lung cancer surgery
Lung cancer surgery
Lung cancer surgery describes the use of surgical operations in the treatment of lung cancer. It involves the surgical excision of cancer tissue from the lung. It is used mainly in non-small cell lung cancer with the intention of curing the patient....
for non-small cell lung cancer. The goal of the surgery can be either the removal of only the tumor, or the entire organ. A single cancer cell is invisible to the naked eye but can regrow into a new tumor, a process called recurrence. For this reason, the pathologist
Anatomical pathology
Anatomical pathology or Anatomic pathology is a medical specialty that is concerned with the diagnosis of disease based on the gross, microscopic, chemical, immunologic and molecular examination of organs, tissues, and whole bodies...
will examine the surgical specimen to determine if a margin of healthy tissue is present, thus decreasing the chance that microscopic cancer cells are left in the patient.
In addition to removal of the primary tumor, surgery is often necessary for staging
Cancer staging
The stage of a cancer is a description of the extent the cancer has spread. The stage often takes into account the size of a tumor, how deeply it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to , and whether it has spread to distant organs...
, e.g. determining the extent of the disease and whether it has metastasized
Metastasis
Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
to regional lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s. Staging is a major determinant of prognosis
Prognosis
Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
and of the need for adjuvant therapy.
Occasionally, surgery is necessary to control symptoms, such as spinal cord compression
Spinal cord compression
Spinal cord compression develops when the spinal cord is compressed by bone fragments from a vertebral fracture, a tumor, abscess, ruptured intervertebral disc or other lesion...
or bowel obstruction
Bowel obstruction
Bowel obstruction is a mechanical or functional obstruction of the intestines, preventing the normal transit of the products of digestion. It can occur at any level distal to the duodenum of the small intestine and is a medical emergency...
. This is referred to as palliative treatment.
If surgery is possible and appropriate, it is commonly performed before other forms of treatment, although the order does not affect the outcome. In some instances, surgery must be delayed until other treatments are able to shrink the tumor.
Radiation therapy
Radiation therapyRadiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
(also called radiotherapy, X-ray therapy, or irradiation) is the use of ionizing radiation to kill cancer cells and shrink tumors. Radiation therapy can be administered externally via external beam radiotherapy
External beam radiotherapy
External beam radiotherapy or teletherapy is the most common form of radiotherapy. The patient sits or lies on a couch and an external source of radiation is pointed at a particular part of the body...
(EBRT) or internally via brachytherapy
Brachytherapy
Brachytherapy , also known as internal radiotherapy, sealed source radiotherapy, curietherapy or endocurietherapy, is a form of radiotherapy where a radiation source is placed inside or next to the area requiring treatment...
. The effects of radiation therapy are localised and confined to the region being treated. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. Hence, it is given in many fractions, allowing healthy tissue to recover between fractions.
Radiation therapy may be used to treat almost every type of solid tumor, including cancers of the brain, breast, cervix, larynx, lung, pancreas, prostate, skin, stomach, uterus, or soft tissue sarcomas. Radiation is also used to treat leukemia and lymphoma. Radiation dose to each site depends on a number of factors, including the radiosensitivity of each cancer type and whether there are tissues and organs nearby that may be damaged by radiation. Thus, as with every form of treatment, radiation therapy is not without its side effects.
Chemotherapy
ChemotherapyChemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
is the treatment of cancer with drugs
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
("anticancer drugs") that can destroy cancer cells. In current usage, the term "chemotherapy" usually refers to cytotoxic drugs which affect rapidly dividing cells in general, in contrast with targeted therapy (see below). Chemotherapy drugs interfere with cell division in various possible ways, e.g. with the duplication of DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
or the separation of newly formed chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s. Most forms of chemotherapy target all rapidly dividing cells and are not specific to cancer cells, although some degree of specificity may come from the inability of many cancer cells to repair DNA damage, while normal cells generally can. Hence, chemotherapy has the potential to harm healthy tissue, especially those tissues that have a high replacement rate (e.g. intestinal lining). These cells usually repair themselves after chemotherapy.
Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called "combination chemotherapy"; most chemotherapy regimens are given in a combination.
The treatment of some leukaemias and lymphoma
Lymphoma
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
s requires the use of high-dose chemotherapy, and total body irradiation
Total body irradiation
Total body irradiation is a form of radiotherapy used primarily as part of the preparative regimen for haematopoietic stem cell transplantation. As the name implies, TBI involves irradiation of the entire body, though in modern practice the lungs are often partially shielded to lower the risk of...
(TBI). This treatment ablates the bone marrow, and hence the body's ability to recover and repopulate the blood. For this reason, bone marrow, or peripheral blood stem cell harvesting is carried out before the ablative part of the therapy, to enable "rescue" after the treatment has been given. This is known as autologous stem cell transplantation. Alternatively, hematopoietic stem cells may be transplanted from a matched unrelated donor (MUD).
Targeted therapies
Targeted therapy, which first became available in the late 1990s, has had a significant impact in the treatment of some types of cancer, and is currently a very active research area. This constitutes the use of agents specific for the deregulated proteins of cancer cells. Small moleculeSmall molecule
In the fields of pharmacology and biochemistry, a small molecule is a low molecular weight organic compound which is by definition not a polymer...
targeted therapy drugs are generally inhibitors of enzymatic
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
domains on mutated, overexpressed, or otherwise critical proteins within the cancer cell. Prominent examples are the tyrosine kinase inhibitors imatinib
Imatinib
Imatinib is a drug used to treat certain types of cancer. It is currently marketed by Novartis as Gleevec or Glivec as its mesylate salt, imatinib mesilate . It is used in treating chronic myelogenous leukemia , gastrointestinal stromal tumors and some other diseases...
(Gleevec/Glivec) and gefitinib
Gefitinib
Gefitinib INN , trade name Iressa, is a drug used in the treatment of certain types of cancer, particularly those with mutated and overactive EGFR. Gefitinib is an EGFR inhibitor, like erlotinib, which interrupts signaling through the epidermal growth factor receptor in target cells...
(Iressa).
Monoclonal antibody therapy
Monoclonal antibody therapy
Monoclonal antibody therapy is the use of monoclonal antibodies to specifically bind to target cells or proteins. This may then stimulate the patient's immune system to attack those cells...
is another strategy in which the therapeutic agent is an antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
which specifically binds to a protein on the surface of the cancer cells. Examples include the anti-HER2/neu
HER2/neu
HER-2 also known as proto-oncogene Neu, receptor tyrosine-protein kinase erbB-2, CD340 or p185 is an enzyme that in humans is encoded by the ERBB2 gene. Over expression of this gene is correlated with higher aggressiveness in breast cancers...
antibody trastuzumab
Trastuzumab
Trastuzumab is a monoclonal antibody that interferes with the HER2/neu receptor.The HER receptors are proteins that are embedded in the cell membrane and communicate molecular signals from outside the cell to inside the cell, and turn genes on and off...
(Herceptin) used in breast cancer, and the anti-CD20 antibody rituximab
Rituximab
Rituximab, sold under the trade names Rituxan and MabThera, is a chimeric monoclonal antibody against the protein CD20, which is primarily found on the surface of B cells...
, used in a variety of B-cell malignancies.
Targeted therapy
Targeted therapy
Targeted therapy is a type of medication that blocks the growth of cancer cells by interfering with specific targeted molecules needed for carcinogenesis and tumor growth, rather than by simply interfering with rapidly dividing cells...
can also involve small peptide
Peptide
Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...
s as "homing devices" which can bind to cell surface receptors or affected extracellular matrix
Extracellular matrix
In biology, the extracellular matrix is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals.Extracellular...
surrounding the tumor. Radionuclides which are attached to these peptides (e.g. RGDs) eventually kill the cancer cell if the nuclide decays in the vicinity of the cell. Especially oligo- or multimers of these binding motifs are of great interest, since this can lead to enhanced tumor specificity and avidity.
Photodynamic therapy
Photodynamic therapy
Photodynamic therapy is used clinically to treat a wide range of medical conditions, including malignant cancers, and is recognised as a treatment strategy which is both minimally invasive and minimally toxic...
(PDT) is a ternary treatment for cancer involving a photosensitizer, tissue oxygen, and light (often using lasers). PDT can be used as treatment for basal cell carcinoma
Basal cell carcinoma
Basal-cell carcinoma is the most common type of skin cancer. It rarely metastasizes or kills. However, because it can cause significant destruction and disfigurement by invading surrounding tissues, it is still considered malignant. Statistically, approximately 3 out of 10 Caucasians may develop a...
(BCC) or lung cancer
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
; PDT can also be useful in removing traces of malignant tissue after surgical removal of large tumors.
Immunotherapy
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
to fight the tumor. Contemporary methods for generating an immune response against tumours include intravesical BCG
Bacillus Calmette-Guérin
Bacillus Calmette-Guérin is a vaccine against tuberculosis that is prepared from a strain of the attenuated live bovine tuberculosis bacillus, Mycobacterium bovis, that has lost its virulence in humans by being specially subcultured in an artificial medium for 13 years, and also prepared from...
immunotherapy for superficial bladder cancer, and use of interferon
Interferon
Interferons are proteins made and released by host cells in response to the presence of pathogens—such as viruses, bacteria, or parasites—or tumor cells. They allow communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors.IFNs belong to...
s and other cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...
s to induce an immune response in renal cell carcinoma
Renal cell carcinoma
Renal cell carcinoma is a kidney cancer that originates in the lining of the proximal convoluted tubule, the very small tubes in the kidney that filter the blood and remove waste products. RCC is the most common type of kidney cancer in adults, responsible for approximately 80% of cases...
and melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
patients. Vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
s to generate specific immune responses are the subject of intensive research for a number of tumours, notably malignant melanoma and renal cell carcinoma
Renal cell carcinoma
Renal cell carcinoma is a kidney cancer that originates in the lining of the proximal convoluted tubule, the very small tubes in the kidney that filter the blood and remove waste products. RCC is the most common type of kidney cancer in adults, responsible for approximately 80% of cases...
. Sipuleucel-T
Sipuleucel-T
Sipuleucel-T , manufactured by Dendreon Corporation, is a therapeutic cancer vaccine for prostate cancer . It must be prepared specifically for each patient. In metastatic prostate cancer, it has extended survival by about four months...
is a vaccine-like strategy in late clinical trials for prostate cancer
Prostate cancer
Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, there are cases of aggressive prostate cancers. The cancer cells may metastasize from the prostate to other parts of the body, particularly...
in which dendritic cell
Dendritic cell
Dendritic cells are immune cells forming part of the mammalian immune system. Their main function is to process antigen material and present it on the surface to other cells of the immune system. That is, dendritic cells function as antigen-presenting cells...
s from the patient are loaded with prostatic acid phosphatase
Prostatic acid phosphatase
Prostatic acid phosphatase , also prostatic specific acid phosphatase , is an enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer or other diseases....
peptides to induce a specific immune response against prostate-derived cells.
Allogeneic hematopoietic stem cell transplantation ("bone marrow transplantation" from a genetically non-identical donor) can be considered a form of immunotherapy, since the donor's immune cells will often attack the tumor in a phenomenon known as graft-versus-tumor effect. For this reason, allogeneic HSCT leads to a higher cure rate than autologous transplantation for several cancer types, although the side effects are also more severe.
The cell based immunotherapy in which the patients own Natural Killer cells(NK) and Cytotoxic T-Lymphocytes(CTL) are used has been in practice in Japan since 1990. NK cells and CTLs primarily kill the cancer cells when they are developed. This treatment is given together with the other modes of treatment such as Surgery, radiotherapy or Chemotherapy and called as Autologous Immune Enhancement Therapy (AIET)
Hormonal therapy
The growth of some cancers can be inhibited by providing or blocking certain hormones. Common examples of hormone-sensitive tumors include certain types of breast and prostate cancers. Removing or blocking estrogenEstrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
or testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
is often an important additional treatment. In certain cancers, administration of hormone agonists, such as progestogens may be therapeutically beneficial.
Angiogenesis inhibitors
Angiogenesis inhibitors prevent the extensive growth of blood vessels (angiogenesisAngiogenesis
Angiogenesis is the physiological process involving the growth of new blood vessels from pre-existing vessels. Though there has been some debate over terminology, vasculogenesis is the term used for spontaneous blood-vessel formation, and intussusception is the term for the formation of new blood...
) that tumors require to survive. Some, such as bevacizumab
Bevacizumab
Bevacizumab is a drug that blocks angiogenesis, the growth of new blood vessels. It is commonly used to treat various cancers, including colorectal, lung, breast, kidney, and glioblastomas....
, have been approved and are in clinical use. One of the main problems with anti-angiogenesis drugs is that many factors stimulate blood vessel growth in cells normal or cancerous. Anti-angiogenesis drugs only target one factor, so the other factors continue to stimulate blood vessel growth. Other problems include route of administration
Route of administration
A route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body.-Classification:Routes of administration are usually classified by application location...
, maintenance of stability and activity and targeting at the tumor vasculature.
Symptom control and palliative care
Although the control of the symptoms of cancer is not typically thought of as a treatment directed at the cancer, it is an important determinant of the quality of lifeQuality of life
The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and politics. Quality of life should not be confused with the concept of standard of...
of cancer patients, and plays an important role in the decision whether the patient is able to undergo other treatments. Although doctors generally have the therapeutic skills to reduce pain, Chemotherapy-induced nausea and vomiting
Chemotherapy-induced nausea and vomiting
Chemotherapy-induced nausea and vomiting is a common side-effect of many cancer treatments. Nausea and vomiting are two of the most feared cancer treatment-related side effects for cancer patients and their families. In 1983, Coates et al. found that patients receiving chemotherapy ranked nausea...
, diarrhea, hemorrhage and other common problems in cancer patients, the multidisciplinary specialty of palliative care
Palliative care
Palliative care is a specialized area of healthcare that focuses on relieving and preventing the suffering of patients...
has arisen specifically in response to the symptom control needs of this group of patients.
Pain medication, such as morphine
Morphine
Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
and oxycodone
Oxycodone
Oxycodone is an opioid analgesic medication synthesized from opium-derived thebaine. It was developed in 1916 in Germany, as one of several new semi-synthetic opioids in an attempt to improve on the existing opioids: morphine, diacetylmorphine , and codeine.Oxycodone oral medications are generally...
, and antiemetic
Antiemetic
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....
s, drugs to suppress nausea and vomiting, are very commonly used in patients with cancer-related symptoms. Improved antiemetics such as ondansetron
Ondansetron
Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic , often following chemotherapy. Its effects are thought to be on both peripheral and central nerves...
and analogues, as well as aprepitant
Aprepitant
Aprepitant is an antiemetic chemical compound that belongs to a class of drugs called substance P antagonists . It mediates its effect by blocking the neurokinin 1 receptor.Aprepitant is manufactured by Merck & Co...
have made aggressive treatments much more feasible in cancer patients.
Cancer pain
Cancer pain
Pain is a symptom frequently associated with cancer. Cancer can cause pain by irritating or damaging nerves, by stimulating nociceptors , or by releasing chemicals that make nociceptors respond to normally non-painful stimuli. Cancer pain may be caused by the tumor itself or by medical...
can be associated with continuing tissue damage due to the disease process or the treatment (i.e. surgery, radiation, chemotherapy). Although there is always a role for environmental factors and affective disturbances in the genesis of pain behaviors, these are not usually the predominant etiologic factors in patients with cancer pain. Some patients with severe pain associated with cancer are nearing the end of their lives, but in all cases palliative therapies should be used to control the pain. Issues such as social stigma of using opioids, work and functional status, and health care consumption can be concerns and may need to be addressed in order for the person to feel comfortable taking the medications required to control his or her symptoms. The typical strategy for cancer pain management is to get the patient as comfortable as possible using the least amount of medications possible but opioids, surgery, and physical measures are often required. In the past doctors have been reluctant to prescribe narcotics for pain in terminal cancer patients, for fear of contributing to addiction or suppressing respiratory function. The palliative care
Palliative care
Palliative care is a specialized area of healthcare that focuses on relieving and preventing the suffering of patients...
movement, a more recent offshoot of the hospice
Hospice
Hospice is a type of care and a philosophy of care which focuses on the palliation of a terminally ill patient's symptoms.In the United States and Canada:*Gentiva Health Services, national provider of hospice and home health services...
movement, has engendered more widespread support for preemptive pain treatment for cancer patients. The World Health Organization
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
also noted uncontrolled cancer pain as a worldwide problem and established a "ladder" as a guideline for how practitioners should treat pain in patients who have cancer
Cancer-related fatigue
Cancer-related fatigue
Cancer-related fatigue is a subjective symptom of fatigue that is experienced by nearly all cancer patients.Among patients receiving cancer treatment other than surgery, it is essentially universal. Fatigue is a normal and expected side effect from most forms of chemotherapy, radiation therapy,...
is a very common problem for cancer patients, and has only recently become important enough for oncologists to suggest treatment, even though it plays a significant role in many patients' quality of life.
Hospice in cancer
HospiceHospice
Hospice is a type of care and a philosophy of care which focuses on the palliation of a terminally ill patient's symptoms.In the United States and Canada:*Gentiva Health Services, national provider of hospice and home health services...
is a group that provides care at the home of a person that has an advanced illness with a likely prognosis of less than 6 months. As most treatments for cancer involve significant unpleasant side effects, a patient with little realistic hope of a cure or prolonged life may choose to seek comfort care only, forgoing more radical therapies in exchange for a prolonged period of normal living. This is an especially important aspect of care for those patients whose disease is not a good candidate for other forms of treatment. In these patients, the risks related to the chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
may actually be higher than the chance of responding to the treatment, making further attempts to cure the disease impossible. Of note, patients on hospice can sometimes still get treatments such as radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
therpy if it is being used to treat symptoms, not as an attempt to cure the cancer.
Research
Clinical trialClinical trial
Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety and efficacy data to be collected for health interventions...
s, also called research studies, test new treatments in people with cancer. The goal of this research is to find better ways to treat cancer and help cancer patients. Clinical trials test many types of treatment such as new drugs, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy
Gene therapy
Gene therapy is the insertion, alteration, or removal of genes within an individual's cells and biological tissues to treat disease. It is a technique for correcting defective genes that are responsible for disease development...
.
A clinical trial is one of the final stages of a long and careful cancer research process. The search for new treatments begins in the laboratory, where scientists first develop and test new ideas. If an approach seems promising, the next step may be testing a treatment in animals to see how it affects cancer in a living being and whether it has harmful effects. Of course, treatments that work well in the lab or in animals do not always work well in people. Studies are done with cancer patients to find out whether promising treatments are safe and effective.
Patients who take part may be helped personally by the treatment they receive. They get up-to-date care from cancer experts, and they receive either a new treatment being tested or the best available standard treatment for their cancer. At the same time, new treatments also may have unknown risks, but if a new treatment proves effective or more effective than standard treatment, study patients who receive it may be among the first to benefit. There is no guarantee that a new treatment being tested or a standard treatment will produce good results. In children with cancer, a survey of trials found that those enrolled in trials were on average not more likely to do better or worse than those on standard treatment; this confirms that success or failure of an experimental treatment cannot be predicted.
Exosome research
ExosomesExosome (vesicle)
Exosomes are 30-90 nm vesicles secreted by a wide range of mammalian cell types. First discovered in maturing mammalian reticulocytes, they were shown to be a mechanism for selective removal of many plasma membrane proteins. These proteins are lost or reduced in amount, without concomitant...
are lipid-covered microvesicles shed by solid tumors into bodily fluids, such as blood and urine. Current research is being done attempting to use exosomes as a detection and monitoring method for a variety of cancers., The hope is to be able to detect cancer with a high sensitivity and specificity via detection of specific exosomes in the blood or urine. The same process can be used to more accurately monitor a patients treatment progress as well. Enzyme linked lectin specific assay or ELLSA has been proven to directly detect melanoma derived exosomes from fluid samples. Previously, exosomes had been measured by total protein content in purified samples and by indirect immunomodulatory effects. ELLSA directly measures exosome particles in complex solutions, and has already been found capable of detecting exosomes from other sources, including ovarian cancer and tuberculosis-infected macrophages.
Exosomes secreted by tumors are also believed to be responsible for triggering programmed cell death (apoptosis) of immune cells; interrupting T-cell signaling required to mount an immune response; inhibiting the production of anti-cancer cytokines, and has implications in the spread of metastasis and allowing for angiogenesis. Studies are currently being done with Lectin Affinity Plasmapheresis (LAP), LAP is a blood filtration method which selectively targets the tumor based exosomes and removes them from the bloodstream. It is believed that decreasing the tumor secreted exosomes in a patients bloodstream will slow down progression of the cancer while at the same time increase the patients own immune response.
Complementary and alternative
Complementary and alternative medicineAlternative medicine
Alternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....
(CAM) treatments are the diverse group of medical and health care systems, practices, and products that are not part of conventional medicine and have not been shown to be effective. "Complementary medicine" refers to methods and substances used along with conventional medicine, while "alternative medicine" refers to compounds used instead of conventional medicine. CAM use is common among people with cancer; a 2000 study found that 69% of cancer patients had used at least one CAM therapy as part of their cancer treatment. Most complementary and alternative medicines for cancer have not been rigorously studied or tested. Some alternative treatments which have been investigated and shown to be ineffective continue to be marketed and promoted.
In pregnancy
The incidence of concurrent cancer during pregnancyPregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
has risen due to the increasing age of pregnant mothers and due to the incidental discovery of maternal tumors during prenatal ultrasound examinations.
Cancer treatment needs to be selected to do least harm to both the woman and her embryo/fetus. In some cases a therapeutic abortion
Therapeutic abortion
Therapeutic abortion is abortion induced following a medical diagnosis. Many therapeutic abortions are performed today, with some degree of controversy regarding the quality of life, if there is a genetic condition in the embryo or fetus which is incompatible with life Therapeutic abortion is...
may be recommended.
Radiation therapy is generally out of the question, and chemotherapy always poses the risk of miscarriage and congenital malformations. Little is known about the effects of medications on the child.
Even if a drug has been tested as not crossing the placenta to reach the child, some cancer forms can harm the placenta and make the drug pass over it anyway. Some forms of skin cancer may even metastasize to the child's body.
Diagnosis is also made more difficult, since computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
is infeasible because of its high radiation dose. Still, magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
works normally. However, contrast media
Contrast medium
A medical contrast medium is a substance used to enhance the contrast of structures or fluids within the body in medical imaging...
cannot be used, since they cross the placenta.
As a consequence of the difficulties to properly diagnose and treat cancer during pregnancy, the alternative methods are either to perform a Cesarean section when the child is viable in order to begin a more aggressive cancer treatment, or, if the cancer is malignant enough that the mother is unlikely to be able to wait that long, to perform an abortion in order to treat the cancer.
In utero
Fetal tumors are sometimes diagnosed while still in utero. TeratomaTeratoma
A teratoma is an encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers. There are rare occasions when not all three germ layers are identifiable...
is the most common type of fetal tumor, and usually is benign.
See also
- Global Task Force on Expanded Access to Cancer Care and Control in Developing CountriesGlobal Task Force on Expanded Access to Cancer Care and Control in Developing CountriesThe Global Task Force on Expanded Access to Cancer Care and Control in Developing Countries is a research and advisory initiative promoted by the Dana Farber Cancer Institute, the , the Harvard Medical School and the Harvard School of Public Health to address the global burden of cancer in...