Cancer-related fatigue
Encyclopedia
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
, and biotherapy
. On average, cancer-related fatigue is "more severe, more distressing, and less likely to be relieved by rest" than fatigue experienced by healthy people. It can range from mild to severe, and may be either temporary or a long-term effect.
Fatigue may be a symptom of the cancer, or it may be the result of treatments for the cancer.
defines cancer-related fatigue as "a distressing persistent, subjective sense of physical, emotional and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning."
Cancer-related fatigue is a chronic
fatigue (persistent fatigue not relieved by rest), the exact process of fatigue is unknown and therefore could be related to Chronic Fatigue Syndrome
, however Chronic Fatigue Syndrome
is not directly associated with cancer.
of cancer-related fatigue is poorly understood. It may be caused by the cancer or the effects it has on the body, by the body's response to the cancer, or by the cancer treatments.
Fatigue is a common symptom
of cancer.
Some fatigue is caused by cancer treatments. This may show a characteristic pattern. For example, people on many chemotherapy regimens often feel more fatigue in the week after treatments, and less fatigue as they recover from that round of medications. People receiving radiation therapy
, by contrast, often find their fatigue steadily increases until the end of treatment.
Proposed mechanisms by which cancer can cause fatigue include an increase in pro-inflammatory cytokines, dysregulation of the hypothalamic-pituitary-adrenal axis
, disruption of circadian rhythm
s, muscle loss and cancer wasting, and genetic problems. Additionally, some forms of cancer may cause fatigue through more direct mechanisms, such as a leukemia
that causes anemia
by preventing the bone marrow
from producing blood cells efficiently.
recommends that every cancer patient be systematically screened for fatigue at the first visit with an oncologist, throughout treatment, and afterwards. Screening
typically involves a simple question, like "On a scale of one to ten
, how tired have you felt during the last week?"
More detailed information may be collected in a symptom journal.
, pain
, emotional distress
, sleep disturbances, nutritional disturbances, decreased physical fitness
and activity, side effects from medications (e.g., sedative
s), abuse of alcohol or other substances. Additionally, other medical conditions
, such as infection
s, heart disease
, or endocrine dysfunction (e.g., hot flashes), can cause fatigue, and may also need treatment.
Some management strategies may help all patients. These include scheduling high-priority tasks during the patient's best time of day, using labor-saving devices, delegating tasks to caregivers, and avoiding unimportant activities, so that the patient will have more energy available for other activities.
Patients who are not at the end of life may benefit from physical exercise or physical therapy
. Engaging in moderate activity reduces fatigue.
While antidepressant
s are ineffective at reducing fatigue in non-depressed cancer patients, the stimulant methylphenidate
(Ritalin) may reduce fatigue in some patients.
At the end of life, fatigue is usually associated with other symptoms, especially anemia, side effects from many medications and previous treatments, and poor nutritional status. Pain, difficulty breathing
, and fatigue form a common symptom cluster. Fatigue often increases as patients with advanced cancer approach death. As a result, people who are dying often sleep much more than a healthy person.
s report fatigue. Under looser definitions, up to half of cancer survivors report fatigue. However, these studies are largely limited to white patients with breast cancer
, or peripheral stem cell transplant or bone marrow transplant
patients, and the incidence may be different for survivors of other cancers.
Experiencing fatigue before treatment, being depressed or anxious, getting too little exercise, and having other medical conditions are all associated with higher levels of fatigue in post-treatment cancer survivors. Receiving multiple types of treatments, such as chemotherapy and radiation, is associated with more fatigue. Older adults have a higher risk of long-term fatigue.
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
of fatigue that is experienced by nearly all cancer
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...
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
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...
, and biotherapy
Biotherapy
Zootherapy is the use of living animals for medical treatment or as an adjunct to medical diagnosis.-Overview:Zootherapy is the use of living organisms to diagnose, treat or cure disease or disease symptoms...
. On average, cancer-related fatigue is "more severe, more distressing, and less likely to be relieved by rest" than fatigue experienced by healthy people. It can range from mild to severe, and may be either temporary or a long-term effect.
Fatigue may be a symptom of the cancer, or it may be the result of treatments for the cancer.
Definition
The National Comprehensive Cancer NetworkNational Comprehensive Cancer Network
National Comprehensive Cancer Network is an alliance of twenty-one cancer centers in the United States, most of which are designated by the National Cancer Institute as comprehensive cancer centers...
defines cancer-related fatigue as "a distressing persistent, subjective sense of physical, emotional and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning."
Cancer-related fatigue is a chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
fatigue (persistent fatigue not relieved by rest), the exact process of fatigue is unknown and therefore could be related to Chronic Fatigue Syndrome
Chronic fatigue syndrome
Chronic fatigue syndrome is the most common name used to designate a significantly debilitating medical disorder or group of disorders generally defined by persistent fatigue accompanied by other specific symptoms for a minimum of six months, not due to ongoing exertion, not substantially...
, however Chronic Fatigue Syndrome
Chronic fatigue syndrome
Chronic fatigue syndrome is the most common name used to designate a significantly debilitating medical disorder or group of disorders generally defined by persistent fatigue accompanied by other specific symptoms for a minimum of six months, not due to ongoing exertion, not substantially...
is not directly associated with cancer.
Pathophysiology
The pathophysiologyPathophysiology
Pathophysiology is the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome...
of cancer-related fatigue is poorly understood. It may be caused by the cancer or the effects it has on the body, by the body's response to the cancer, or by the cancer treatments.
Fatigue is a common symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
of cancer.
Some fatigue is caused by cancer treatments. This may show a characteristic pattern. For example, people on many chemotherapy regimens often feel more fatigue in the week after treatments, and less fatigue as they recover from that round of medications. People receiving 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...
, by contrast, often find their fatigue steadily increases until the end of treatment.
Proposed mechanisms by which cancer can cause fatigue include an increase in pro-inflammatory cytokines, dysregulation of the hypothalamic-pituitary-adrenal axis
Hypothalamic-pituitary-adrenal axis
The hypothalamic-pituitary-adrenal axis , also known as thelimbic-hypothalamic-pituitary-adrenal axis and, occasionally, as the hypothalamic-pituitary-adrenal-gonadotropic axis, is a complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland ,...
, disruption of circadian rhythm
Circadian rhythm
A circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...
s, muscle loss and cancer wasting, and genetic problems. Additionally, some forms of cancer may cause fatigue through more direct mechanisms, such as a leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...
that causes anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
by preventing the bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
from producing blood cells efficiently.
Screening
The National Comprehensive Cancer NetworkNational Comprehensive Cancer Network
National Comprehensive Cancer Network is an alliance of twenty-one cancer centers in the United States, most of which are designated by the National Cancer Institute as comprehensive cancer centers...
recommends that every cancer patient be systematically screened for fatigue at the first visit with an oncologist, throughout treatment, and afterwards. Screening
Screening (medicine)
Screening, in medicine, is a strategy used in a population to detect a disease in individuals without signs or symptoms of that disease. Unlike what generally happens in medicine, screening tests are performed on persons without any clinical sign of disease....
typically involves a simple question, like "On a scale of one to ten
Scale of one to ten
A scale of one to ten or scale from one to ten is a general and largely vernacular concept used for rating things, people, places, ideas, and so on. It is a natural and popular choice of scale used in ordinary speech, along with scales of one to five and then one to four...
, how tired have you felt during the last week?"
More detailed information may be collected in a symptom journal.
Evaluation
Some causes of cancer-related fatigue are treatable, and evaluation is directed towards identifying these treatable causes. Treatable causes of cancer-related fatigue include: anemiaAnemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
, pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
, emotional distress
Emotional distress
Mental distress or anxiety suffered as a response to a sudden, severe, and saddening experience.Emotional distress may refer to:* Law of torts:** Intentional infliction of emotional distress** Negligent infliction of emotional distress* Medicine:...
, sleep disturbances, nutritional disturbances, decreased physical fitness
Physical fitness
Physical fitness comprises two related concepts: general fitness , and specific fitness...
and activity, side effects from medications (e.g., sedative
Sedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....
s), abuse of alcohol or other substances. Additionally, other medical conditions
Comorbidity
In medicine, comorbidity is either the presence of one or more disorders in addition to a primary disease or disorder, or the effect of such additional disorders or diseases.- In medicine :...
, such as infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s, heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
, or endocrine dysfunction (e.g., hot flashes), can cause fatigue, and may also need treatment.
Management
Treatment depends on the patient's overall situation. A patient who is in active treatment may have different priorities than a person who has completed treatment, or who is at the end of life.Some management strategies may help all patients. These include scheduling high-priority tasks during the patient's best time of day, using labor-saving devices, delegating tasks to caregivers, and avoiding unimportant activities, so that the patient will have more energy available for other activities.
Patients who are not at the end of life may benefit from physical exercise or physical therapy
Physical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
. Engaging in moderate activity reduces fatigue.
While antidepressant
Antidepressant
An antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder. According to Gelder, Mayou &*Geddes people with a depressive illness will experience a therapeutic effect to their mood;...
s are ineffective at reducing fatigue in non-depressed cancer patients, the stimulant methylphenidate
Methylphenidate
Methylphenidate is a psychostimulant drug approved for treatment of attention-deficit hyperactivity disorder, postural orthostatic tachycardia syndrome and narcolepsy. It may also be prescribed for off-label use in treatment-resistant cases of lethargy, depression, neural insult and obesity...
(Ritalin) may reduce fatigue in some patients.
At the end of life, fatigue is usually associated with other symptoms, especially anemia, side effects from many medications and previous treatments, and poor nutritional status. Pain, difficulty breathing
Dyspnea
Dyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...
, and fatigue form a common symptom cluster. Fatigue often increases as patients with advanced cancer approach death. As a result, people who are dying often sleep much more than a healthy person.
Addressing specific causes
If the fatigue is caused or exacerbated by a specific medical condition, such as anemia, then treatment of that medical condition should reduce the fatigue.- AnemiaAnemiaAnemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
: Loss of oxygen-carrying red blood cells is a common cause of fatigue. Medications to improve blood production or blood transfusionBlood transfusionBlood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
s frequently reduce fatigue. - PainPainPain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
: A variety of approaches to managing painPain managementPain management is a branch of medicine employing an interdisciplinary approach for easing the suffering and improving the quality of life of those living with pain. The typical pain management team includes medical practitioners, clinical psychologists, physiotherapists, occupational therapists,...
may be used, particularly analgesicAnalgesicAn analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
medications. - Emotional distressEmotional distressMental distress or anxiety suffered as a response to a sudden, severe, and saddening experience.Emotional distress may refer to:* Law of torts:** Intentional infliction of emotional distress** Negligent infliction of emotional distress* Medicine:...
: Anxiety and depression are strongly associated with fatigue in cancer patients. PsychosocialPsychosocialFor a concept to be psychosocial means it relates to one's psychological development in, and interaction with, a social environment. The individual needs not be fully aware of this relationship with his or her environment. It was first commonly used by psychologist Erik Erikson in his stages of...
treatments directed at reducing stress and increasing coping skills may reduce fatigue. Additionally, some patients in active treatment worry that the fatigue indicates treatment failure, and this anxiety may increase their fatigue in a vicious cycle. Education about fatigue as a normal side effect can reassure the patient. Up to 25% of cancer patients will experience depression. - Sleep disturbances: Patients who do not sleep well are more tired than others. Cancer patients commonly experience insomniaInsomniaInsomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
or hypersomniaHypersomniaHypersomnia is a disorder characterized by excessive amounts of sleepiness.There are two main categories of hypersomnia: primary hypersomnia and recurrent hypersomnia...
. Sleep disturbances may be caused by sleeping too much during the day, by restless leg syndrome, by pain, by anxiety, or by other medical conditions, like obstructive sleep apneaObstructive sleep apneaObstructive sleep apnea or obstructive sleep apnea syndrome is the most common type of sleep apnea and is caused by obstruction of the upper airway. It is characterized by repetitive pauses in breathing during sleep, despite the effort to breathe, and is usually associated with a reduction in...
or menopauseMenopauseMenopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
. Practicing good sleep hygieneSleep hygieneSleep hygiene can be defined as the controlling of "all behavioural and environmental factors that precede sleep and may interfere with sleep." It is the practice of following guidelines in an attempt to ensure more restful, effective sleep which can promote daytime alertness and help treat or...
may reduce fatigue by improving sleep quality. - Nutritional disturbances: Patients may have difficulty eating, may not be absorbing food well, or may have chosen an extreme diet as an alternative cancer treatment. Loss of appetite, diarrheaDiarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
and vomiting may result in the patient consuming too few calories or becoming dehydrated. - Physical fitnessPhysical fitnessPhysical fitness comprises two related concepts: general fitness , and specific fitness...
decreases with inactivity and so fatigue increases. - Side effects from medications: Fatigue and sleepiness are known side effects with some kinds of medications. Sometimes a change of medication, the dose, or the timing of the medication may result in less fatigue. For example, an antihistamineAntihistamineAn H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...
might be taken shortly before sleep, rather than in the middle of the day. - Substance abuseSubstance abuseA substance-related disorder is an umbrella term used to describe several different conditions associated with several different substances .A substance related disorder is a condition in which an individual uses or abuses a...
: AlcoholAlcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
, marijuana, and many other drugsDepressantA depressant, or central depressant, is a drug or endogenous compound that depresses the function or activity of a specific part of the brain...
can produce fatigue as a side effect. - Other medical conditions: Cancer and its treatment usually put intense physical stress on the body, which can exacerbate other medical conditions. Additionally, fatigue may result from an infection.
Prognosis
Fatigue caused by the cancer or its treatment often resolves if treatment is successful. However, some patients experience long-term fatigue. When strict definitions are used, about 20% of long-term, disease-free cancer survivorCancer survivor
A cancer survivor is an individual with cancer of any type, current or past, who is still living. About 11 million Americans alive today—one in 30 people–are either currently undergoing treatment for cancer or have done so in the past." Currently nearly 65% of adults diagnosed with cancer in the...
s report fatigue. Under looser definitions, up to half of cancer survivors report fatigue. However, these studies are largely limited to white patients with breast cancer
Breast cancer
Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...
, or peripheral stem cell transplant or bone marrow transplant
Bone marrow transplant
Hematopoietic stem cell transplantation is the transplantation of multipotent hematopoietic stem cell or blood, usually derived from bone marrow, peripheral blood stem cells, or umbilical cord blood...
patients, and the incidence may be different for survivors of other cancers.
Experiencing fatigue before treatment, being depressed or anxious, getting too little exercise, and having other medical conditions are all associated with higher levels of fatigue in post-treatment cancer survivors. Receiving multiple types of treatments, such as chemotherapy and radiation, is associated with more fatigue. Older adults have a higher risk of long-term fatigue.