Fertility preservation
Fertility preservation is the effort to help cancer patients retain their fertility, or ability to procreate. Research into how cancer, ageing and other health conditions effect reproductive health and preservation options are growing. Specifically sparked in part by the increase in the survival rate of cancer patients.[1]
Indications
Fertility preservation procedures are indicated when it is predicted that there will be exposure to a cause of
Chemotherapy and radiotherapy
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.[5] Surgery involving reproductive tissue affects reproductive function and fertility.
For some patients receiving chemotherapy or radiotherapy, the decrease or loss of reproductive function is temporary; many men and females, however, do not regain fertility after this treatment. The extent of the damage to ovaries resulting in diminished fertility can be associated with the chemotherapeutic regiment such as the combination of chemotherapy and radiotherapy (
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.[9] 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.[9] No serious clinical sequelae resulted from participation.[9]
Prior to females undergoing these treatments, a testing for the level of anti-Müllerian hormone (AMH) is useful in predicting the long-term post-chemotherapy loss of ovarian function, in turn predicting the need for fertility preservation strategies in the future.[10]
Ageing
Increasing age in females is directly associated with decreasing reproductive potential. This can be the result of many factors such as the amount of eggs available and their overall reproductive quality.[11] Fertility preservation, such as ovarian tissue or oocyte cryopreservation, may also be used to prevent infertility, as well as birth defects, associated with advanced maternal age.
Males also have decreasing fertility as they age, however this is associated with a problem in sperm quality as opposed to the overall sperm count. These changes can be attributed to the reduction in testosterone males experience when ageing.[12]
PCOS
Polycystic Ovarian Syndrome is the most prevalent endocrine disorder females experience during prime reproductive age.
PCOS has a direct relationship with many health risks such as the development of Type 2 Diabetes, increasing insulin levels, obesity and increased waist size. females with PCOS usually experience
POI
Primary Ovarian Insufficiency is defined as when ovarian function is stopped prematurely (before the age of 40). This is also known premature ovarian failure or premature menopause. Ovarian deficiency causes a reduction in serum oestrogen levels which can lead to infertility, giving a reason for females to seek fertility treatment.
POI can result in a long term risk of serious physical symptoms including bone fragility and heart problems. It has also been linked to psychological distress specifically in regards to fertility loss and the long term consequences of that.[15]
Methods
The main methods of fertility preservation are ovarian protection by
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 masturbation 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
Oocyte cryopreservation
Oocyte cryopreservation involves the extraction and freezing of a female's eggs, to preserve their viability for future use. This is often due to medical reasons such as females undergoing cancer treatment. It is also increasingly being used for elective fertility preservation in females who are not ready to become pregnant but who are conscious of their age-related decline in fertility.[17] This process is different to embryo cryopreservation, where mature eggs are fertilised in vitro (outside the body) with sperm from a donor or partner, and the embryo is frozen. The religious and ethical concerns and legislative restrictions surrounding embryo cryopreservation has prompted significant technical advances in oocyte cryopreservation techniques. Oocyte cryopreservation is now considered a well-established technique for fertility preservation in women.[17]
Embryo cryopreservation
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 female's is in remission from disease. When the female's 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 females, it is not available to pre-pubescent girls, who do not have mature eggs that can be fertilized. females 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 cancer, ovarian cancer, etc.) or those who cannot delay cancer treatment. Alternative methods of hormonal stimulation using letrozole or tamoxifen may be used for females with hormone-sensitive cancers.
Ovarian tissue cryopreservation
Cryopreservation of human ovarian tissue has been successfully carried out around the world to preserve fertility in female cancer patients and in other pathologies where the patient is at increased risk of primary ovarian insufficiency. Most notably, this technique can provide an option for fertility preservation in prepubertal girls. Part of the ovary is removed, frozen and stored until after treatment. The tissue is then thawed and re-implanted.[18] According to a meta-analysis performed in 2017, the success rate of reestablishment of ovarian activity was 63.9%,[19] restoring normal fertility and endocrine function. Over 130 live births have been reported as of June 2017.[20]
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.
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 technology (ART) using in vitro fertilization (IVF) with donor eggs or donor sperm. The resulting embryo can be implanted into the female's's uterus after her endometrium (the lining of the uterus) is stimulated with hormones to prepare for the development of the embryo.
Others
In females requiring local pelvic radiation therapy may benefit from surgical transposition of the ovaries to a site remote from maximal radiation exposure.[22][23]
The use of
Table 1: Main Options of Fertility Preservation
Method | Process | Advantages and Disadvantages | Further Considerations |
Oocyte cryopreservation | |||
Embryo cryopreservation | |||
Ovarian tissue cryopreservation |
Adverse effects
Compared with the general population, people with
Fertility preservation in transgender men
References
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- McLaughlin M, Albertini DF, Wallace WH, Anderson RA, Telfer EE (March 2018). "Metaphase II oocytes from human unilaminar follicles grown in a multi-step culture system". Molecular Human Reproduction. 24 (3): 135–142. PMID 29390119.
- Further comments in BBC News article: James Gallagher (2018-02-09). "First human eggs grown in laboratory". BBC News.
- McLaughlin M, Albertini DF, Wallace WH, Anderson RA, Telfer EE (March 2018). "Metaphase II oocytes from human unilaminar follicles grown in a multi-step culture system". Molecular Human Reproduction. 24 (3): 135–142.
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Further reading
- American Society for Reproductive Medicine (November 2013). "Fertility preservation in patients undergoing gonadotoxic therapy or gonadectomy: a committee opinion". Fertility and Sterility. 100 (5): 1214–23. PMID 24011612.
- Mayo Foundation for Medical Education and Research (2007). "Cancer treatment for men: Possible sexual side effects". MayoClinic.com.
- Magelssen H, Brydøy M, Fosså SD (June 2006). "The effects of cancer and cancer treatments on male reproductive function". Nature Clinical Practice. Urology. 3 (6) (6 ed.): 312–22. S2CID 22154508.
- von Wolff M, Montag M, Dittrich R, Denschlag D, Nawroth F, Lawrenz B (August 2011). "Fertility preservation in women--a practical guide to preservation techniques and therapeutic strategies in breast cancer, Hodgkin's lymphoma and borderline ovarian tumours by the fertility preservation network FertiPROTEKT". Archives of Gynecology and Obstetrics. 284 (2): 427–35. PMID 21431846.
- Gracia C, Woodruff TK (2012). Oncofertility Medical Practice: Clinical Issues and Implementation. Springer. ISBN 978-1-441-99425-7.
External links
- Fertility Preservation, ReproTech website
- Semen Storage through Cryopreservation
- Embryo Storage through Cryopreservation
- Oocyte Cryostorage
- Ovarian Tissue Cryostorage Services
- http://oncofertility.northwestern.edu
- http://savemyfertility.org/
- FertiPROTEKT, network for fertility protection of German-speaking countries