Fertility preservation
Encyclopedia
Fertility preservation is the effort to help cancer patients retain their fertility
, or ability to procreate. Research into how cancer affects reproductive health and preservation options are growing, sparked in part by the increase in the survival rate of cancer patients.
, mainly cancer treatment.
to the pelvic area and some types of chemotherapy
. Chemotherapies with high risk include procarbazine
and alkylating drugs such as cyclophosphamide
, ifosfamide, busulfan, melphalan, chlorambucil and chlormethine. Drugs with medium risk include doxorubicin and platinum analogs such as cisplatin and carboplatin. On the other hand, therapies with low risk of gonadotoxicity include plant derivatives such as vincristine and vinblastine, antibiotics such as bleomycinand dactinomycin and antimetabolites such as methotrexate, mercaptopurine and 5-fluoruracil.
These regimens attack rapidly dividing cells in the body, including healthy cells like sperm
and those belonging to the ovarian follicle (egg). Depending on the dose and duration of administration, these therapies can have varying effects on reproductive health. Surgery involving reproductive tissue affects reproductive function and fertility.
For many cancer patients, the decrease or loss of reproductive function is temporary; many men and women, however, do not regain fertility after cancer treatment. Patients undergoing serious radiation, chemotherapy, or surgery sometimes experience symptoms resembling menopause
(in women) or andropause (in men), which indicate reproductive damage. In women, decreased estrogen
levels as a result of ovarian deficiency lead to weakened bone, changes in temperature control, altered mood, and decreased sexual desire. Men with testicular insufficiency also experience similar symptoms.
A study indicated that fewer oocytes are recovered from cancer patients wanting to perform embryo preservation when compared with an age-matched control group, but the mean number of zygotes generated appears to be similar. The same study found that, of 65 patients referred to the program, 28% declined to undergo embryo, oocyte, or tissue cryopreservation. 9% were found not to be eligible for medical reasons. Of the remaining 41 patients, 85% chose to cryopreserve embryos, 10% chose to cryopreserve oocytes, and 5% chose to undergo ovarian tissue freezing. No serious clinical sequelae resulted from participation.
or oocyte cryopreservation
, may also be used to prevent infertility, as well as birth defects, associated with advanced maternal age
.
, cryopreservation
of ovarian tissue, eggs or sperm, or of embryos after in vitro fertilization. The patient may also choose to use egg or sperm from a donor by third party reproduction
rather than having biological children.
in post-pubescent boys and men. This is the most established fertility preservation method for males. For pre-pubescent boys, sperm can be obtained through testicular aspiration or electrostimulation and then stored for future use. Researchers are also looking at methods for cryopreserving testicular tissue samples so that they can be re-implanted into the body after treatment.
, ovarian cancer
, etc) or those who cannot delay cancer treatment. Alternative methods of hormonal stimulation using letrozole or tamoxifen may be used for women with hormone-sensitive cancers.
Strips of cortical ovarian tissue can also be cryopreserved, but it must be re-implanted into the body to allow the encapsulated immature follicles to complete their maturation. Furthermore, ovarian tissue is fragile under hard freezing conditions and putting it back into the body carries the risk of re-introducing cancerous cells.
Immature eggs are more tolerant of cryopreservation conditions but still cannot be effectively matured outside of the body. Thus far, this has generated two live births in mice, and scientists are working to translate these methods to humans.
(ART) using in vitro fertilization (IVF) with donor eggs or donor sperm. The resulting embryo can be implanted into the woman's uterus after her endometrium
(the lining of the uterus) is stimulated with hormones to prepare for the development of the embryo.
Fertility
Fertility is the natural capability of producing offsprings. As a measure, "fertility rate" is the number of children born per couple, person or population. Fertility differs from fecundity, which is defined as the potential for reproduction...
, or ability to procreate. Research into how cancer affects reproductive health and preservation options are growing, sparked in part by the increase in the survival rate of cancer patients.
Indications
Fertility preservation procedures are indicated when it's predicted that there will be exposure to a cause of infertilityInfertility
Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...
, mainly cancer treatment.
Cancer treatment
Chemotherapy and radiation treatments for cancer and other serious illnesses can affect reproductive health. The regimens that threaten ovarian and testicular function are mainly 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...
to the pelvic area and some types 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....
. Chemotherapies with high risk include procarbazine
Procarbazine
Procarbazine Procarbazine Procarbazine (Matulane (US), Natulan (Canada), Indicarb (India) is an antineoplastic chemotherapy drug for the treatment of Hodgkin's lymphoma and certain brain cancers (such as Glioblastoma multiforme). It is a member of a group of medicines called alkylating agents. It...
and alkylating drugs such as cyclophosphamide
Cyclophosphamide
Cyclophosphamide , also known as cytophosphane, is a nitrogen mustard alkylating agent, from the oxazophorines group....
, ifosfamide, busulfan, melphalan, chlorambucil and chlormethine. Drugs with medium risk include doxorubicin and platinum analogs such as cisplatin and carboplatin. On the other hand, therapies with low risk of gonadotoxicity include plant derivatives such as vincristine and vinblastine, antibiotics such as bleomycinand dactinomycin and antimetabolites such as methotrexate, mercaptopurine and 5-fluoruracil.
These regimens attack rapidly dividing cells in the body, including healthy cells like sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
and those belonging to the ovarian follicle (egg). Depending on the dose and duration of administration, these therapies can have varying effects on reproductive health. Surgery involving reproductive tissue affects reproductive function and fertility.
For many cancer patients, the decrease or loss of reproductive function is temporary; many men and women, however, do not regain fertility after cancer treatment. Patients undergoing serious radiation, chemotherapy, or surgery sometimes experience symptoms resembling menopause
Menopause
Menopause 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...
(in women) or andropause (in men), which indicate reproductive damage. In women, decreased estrogen
Estrogen
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...
levels as a result of ovarian deficiency lead to weakened bone, changes in temperature control, altered mood, and decreased sexual desire. Men with testicular insufficiency also experience similar symptoms.
A study indicated that fewer oocytes are recovered from cancer patients wanting to perform embryo preservation when compared with an age-matched control group, but the mean number of zygotes generated appears to be similar. The same study found that, of 65 patients referred to the program, 28% declined to undergo embryo, oocyte, or tissue cryopreservation. 9% were found not to be eligible for medical reasons. Of the remaining 41 patients, 85% chose to cryopreserve embryos, 10% chose to cryopreserve oocytes, and 5% chose to undergo ovarian tissue freezing. No serious clinical sequelae resulted from participation.
Aging
Fertility preservation, such as ovarian tissueOvarian tissue cryopreservation
Ovarian tissue cryopreservation is cryopreservation of tissue of the ovary of a female.-Indications:Cryopreservation of ovarian tissue is of interest to women who want fertility preservation beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, for example in...
or oocyte cryopreservation
Oocyte cryopreservation
Human oocyte cryopreservation is a novel technology in which a woman’s eggs are extracted, frozen and stored. Later, when she is ready to become pregnant, the eggs can be thawed, fertilized, and transferred to the uterus as embryos.-History:Cryopreservation itself has always played a central role...
, may also be used to prevent infertility, as well as birth defects, associated with advanced maternal age
Advanced maternal age
Advanced maternal age is defined as an increase in the age at which women give birth to their first child, is now a widespread, and indeed near universal, phenomenon across the OECD countries....
.
Methods
The main methods of fertility preservation are ovarian protection by GnRH agonistsGonadotropin-releasing hormone agonist
A gonadotropin-releasing hormone agonist is a synthetic peptide modeled after the hypothalamic neurohormone GnRH that interacts with the gonadotropin-releasing hormone receptor to elicit its biologic response, the release of the pituitary hormones FSH and LH.GnRH agonists are pregnancy category...
, cryopreservation
Cryopreservation
Cryopreservation is a process where cells or whole tissues are preserved by cooling to low sub-zero temperatures, such as 77 K or −196 °C . At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped...
of ovarian tissue, eggs or sperm, or of embryos after in vitro fertilization. The patient may also choose to use egg or sperm from a donor by third party reproduction
Third party reproduction
Third party reproduction refers to a process where another person provides sperm or eggs or where another woman provides her uterus so that a woman can have a child. Thus the reproductive process goes beyond the traditional father-mother model. However, the third party's involvement is limited to...
rather than having biological children.
Semen cryopreservation
Men hoping to preserve their fertility before undergoing treatment for cancer or another fertility-threatening disease can cryopreserve, or freeze, their sperm, which can be obtained through masturbationMasturbation
Masturbation refers to sexual stimulation of a person's own genitals, usually to the point of orgasm. The stimulation can be performed manually, by use of objects or tools, or by some combination of these methods. Masturbation is a common form of autoeroticism...
in post-pubescent boys and men. This is the most established fertility preservation method for males. For pre-pubescent boys, sperm can be obtained through testicular aspiration or electrostimulation and then stored for future use. Researchers are also looking at methods for cryopreserving testicular tissue samples so that they can be re-implanted into the body after treatment.
Cryopreservation of ovarian tissue or oocytes
Some female patients choose to have mature eggs extracted and fertilized outside of the body with sperm from a partner or donor. The resulting embryo is then frozen until the woman is in remission from disease. When the woman is ready to initiate pregnancy, the embryo is thawed and implanted into the uterus for maturation and birth. While this option is the most common fertility preservation method in women, it is not available to pre-pubescent girls, who do not have mature eggs that can be fertilized. Women who do not have a partner will need to use donor sperm. Additionally, because this procedure requires a two-week period of hormonal stimulation to encourage egg maturation, it is not optimal for female patients who are diagnosed with hormone-sensitive cancers (such as breast cancerBreast 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...
, ovarian cancer
Ovarian cancer
Ovarian cancer is a cancerous growth arising from the ovary. Symptoms are frequently very subtle early on and may include: bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses....
, etc) or those who cannot delay cancer treatment. Alternative methods of hormonal stimulation using letrozole or tamoxifen may be used for women with hormone-sensitive cancers.
Strips of cortical ovarian tissue can also be cryopreserved, but it must be re-implanted into the body to allow the encapsulated immature follicles to complete their maturation. Furthermore, ovarian tissue is fragile under hard freezing conditions and putting it back into the body carries the risk of re-introducing cancerous cells.
Immature eggs are more tolerant of cryopreservation conditions but still cannot be effectively matured outside of the body. Thus far, this has generated two live births in mice, and scientists are working to translate these methods to humans.
GnRH agonists
Ongoing trials are assessing the role of ovarian protection by GnRH agonists.Third-party reproduction
Many patients diagnosed with a malignancy or another disease requiring treatment that may impair their fertility consider alternatives to bearing biological children, such as assisted reproductive technologyAssisted reproductive technology
Assisted reproductive technology is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. It is reproductive technology used primarily in infertility treatments. Some forms of ART are also used in fertile couples for genetic reasons...
(ART) using in vitro fertilization (IVF) with donor eggs or donor sperm. The resulting embryo can be implanted into the woman's uterus after her endometrium
Endometrium
-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...
(the lining of the uterus) is stimulated with hormones to prepare for the development of the embryo.
External links
- http://www.cancer.northwestern.edu/fertilitypreservation/
- http://oncofertility.northwestern.edu