What is more stressful in the mind of a patient – a diagnosis of cancer or infertility? An infertile woman’s anxiety and depression scores are equivalent to one with cancer (J Psychosom Obstet Gynecol. 1993;14 Suppl:45-52). These two diseases intersect in the burgeoning field of oncofertility, the collaboration of oncology with reproductive endocrinology to offer patients the option of fertility preservation. The term oncofertility was first coined by Teresa Woodruff, PhD, in 2005 during her invited lecture at the University of Calgary symposium called “Pushing the Boundaries – Advances that Will Change the World in 20 Years.” Her prediction has reached its fruition. This article will review fertility preservation options for female oncology patients.
Dr. Mark P. Trolice
The ability for oncofertility to exist is the result of improved cancer survival rates and advances in reproductive medicine. Improvements in the treatment of cancer enable many young women to survive and focus on the potential of having a family. Malignancies striking young people, particularly breast, lymphoma, and melanoma, have encouraging 5-year survival rates. If invasive cancer is located only in the breast (affecting 62% of women diagnosed), the 5-year survival rate is 99%. For all with Hodgkin lymphoma, the 5-year survival is 87%, increasing to 92% if the cancer is found in its earliest stages. Among all people with melanoma of the skin, from the time of initial diagnosis, the 5-year survival is 92%.
Long-term survival is expected for 80% of children and adolescents diagnosed with cancer (Obstet Gynecol. 2010;116: 1171-83).
Iatrogenic effects
The reproductive risk of cancer treatment is gonadotoxicity and the subsequent iatrogenic primary ovarian insufficiency (POI, prior termed premature ovarian failure) or infertility.
Chemotherapy with alkylating agents, such as cyclophosphamide, is associated with the greatest chance of amenorrhea (Breast Cancer Res Treat. 2014;145:113-28). Chemotherapy with cyclophosphamide, methotrexate, and 5 fluorouracil (CMF – commonly used for the treatment of breast cancer) will usually result in loss of ovarian function in 33% of women under age 30, 50% of women aged 30-35, 75% of women aged 35-40, and 95% of women over age 40 (J Clin Oncol. 2006;24:5769-79).
The dose at which 50% of oocytes are lost due to radiation is under 2 Gy (Hum Reprod. 2003;18:117-21). Unfortunately, the minimum dose decreases with advancing age of the woman, contributed by natural diminishing reserve and an increase in radiosensitivity of oocytes. Age, proximity of the radiation field to the ovaries, and total dose are important factors determining risk of POI. For brain tumors, cranial irradiation may result in hypothalamic amenorrhea.
Protection
The use of GnRH agonist for 6 months during chemotherapy has been controversial with mixed results in avoiding ovarian failure. A recent study suggests a GnRH agonist does reduce the prevalence of POI (J Clin Oncol. 2018;36:1981-90) in women treated for breast cancer but the subsequent ovarian reserve is low (Ann Oncol. 2017;28:1811-6). There are not enough data now to consider this the sole viable option for all patients to preserve fertility.
Patients requiring local pelvic radiation treatment may benefit from transposition of the ovaries to sites away from maximal radiation exposure.
Oocyte cryopreservation (OC) and ovarian tissue cryopreservation (OTC)
Since 2012, the American Society for Reproductive Medicine lifted the experimental designation on OC and, last year, the society removed the same label for OTC, providing an additional fertility preservation option.
Ovarian stimulation and egg retrieval for OC can now occur literally within 2 weeks because of a random start protocol whereby women are stimulated any day in their cycle, pre- and post ovulation. Studies have shown equivalent yield of oocytes.
OC followed by thawing for subsequent fertilization and embryo transfer is employed as a routine matter with egg donation cycles. While there remains debate over whether live birth rates using frozen eggs are inferior to fresh eggs, a learning curve with the new technology may be the important factor (Obstet Gynecol. 2020;135:709-16).
When urgent cancer treatment precludes ovarian stimulation for OC, then OTC is a viable option. Another population that could benefit from OTC are prepubertal girls facing gonadotoxic therapy. More research is required to determine the quality of eggs obtained through ovarian stimulation in adolescent and young adult patients. While leukemic patients are eligible for OTC, there is concern about reseeding malignant cells with future autologous transplantation of tissue.
OTC involves obtaining ovarian cortical tissue, dissecting the tissue into small fragments, and cryopreserving it using either a slow-cool technique or vitrification. Orthotopic transplantation has been the most successful method for using ovarian tissue in humans. To date, live birth rates are modest (Fertil Steril. 2015;104:1097-8).
Recent research has combined the freezing of both mature and immature eggs, the latter undergoing IVM (in-vitro maturation) to maximize the potential for fertilizable eggs. Women with polycystic ovary syndrome and certain cancers or medical conditions that warrant avoiding supraphysiologic levels of estradiol from ovarian stimulation, may benefit from the retrieval of immature eggs from unstimulated ovaries.
Pregnancy outcomes using embryos created from ovaries recently exposed to chemotherapy in humans are not known but animal studies suggest there may be higher rates of miscarriage and birth defects.
Breast cancer – a special scenario
With every breast cancer patient, I review the theoretical concern over increasing estradiol levels during an IVF stimulation cycle with the potential impact on her cancer prognosis. Fortunately, the literature has not demonstrated an increased risk of breast cancer or recurrence after undergoing an IVF cycle. Currently, the use of aromatase inhibitors with gonadotropins along with a GnRH-antagonist is the protocol to maintain a lower estradiol level during stimulation, which may be of benefit for breast cancer prognosis. The use of aromatase inhibitors is an off-label indication for fertility with no definitive evidence of teratogenicity. Preimplantation genetic testing of embryos is available and approved by the American Society for Reproductive Medicine for BRCA gene mutation patients.
Oncofertility is an exciting field to allow cancer survivors the option for a biological child. We recommend all our cancer patients meet with our reproductive psychologist to assist in coping with the overwhelming information presented in a short time frame.
Dr. Trolice is director of Fertility CARE – The IVF Center in Winter Park, Fla., and associate professor of obstetrics and gynecology at the University of Central Florida, Orlando.