Cancer is estimated to affect 100 per 100,000 women in the general population under the age of 50 in the United States. The treatment and survival for cancer has improved dramatically in recent years. Therefore, there is a considerable proportion of cancer survivors in their childbearing years. While it is conventional wisdom that cancer therapy can affect a patient’s fertility potential, less than 25% of oncologists inform their patients about the risks and options for fertility preservation.
Cancer therapy in the form of chemotherapy or radiation therapy, for both malignant and non-malignant diseases, often results in infertility due to premature ovarian failure or arrest of sperm production. Thus, cancer patients, even children, can benefit from the fertility preservation technologies. Such techniques can also be implemented when there is a risk of damaging ovaries or testicles due to surgeries in these organs.
Fertility preservation in cancer patients require individualized therapy, depending on the type of malignancy and chosen therapeutic modality. The optimal treatment also depends on time available before treatment, patient’s age and availability of a sexual partner. In fact, most male cancer patients have long been able to preserve their fertility potential by freezing their sperm prior to therapy.
Fertility options for women have evolved more slowly. In vitro fertilization with embryo transfer is a well-tested procedure that leads to high pregnancy rates (30-40% per frozen embryo cycle). Hormonal stimulation is required for the production of the eggs, which may not be recommended for certain types of cancer. The IVF option would also require that the woman has a partner or be mature enough to pick an anonymous sperm donor. Another consideration is that if the patient does not survive her cancer, the frozen embryos could potentially be left behind, raising ethical issues for their ultimate use.
For the patient who cannot freeze eggs or embryos, an egg donor may be a viable alternative. Pregnancy rates with egg donors that can be fertilized with a partner/donor sperm and transferred to the patient’s uterus are very high, as long as the donor has good quality egg and the patient has a healthy uterus.
Ovarian tissue freezing
Many oncologists do not support the use of assisted reproductive technologies because it involves the exposure of a cancer patient to high levels of estrogen, which could be detrimental in women who have estrogen-dependent tumors. For these women, ovarian tissue freezing may be an option. This therapeutic modality does not require hormonal stimulation and may be used in pre-pubertal patients. Many immature eggs may be preserved this way, but extensive laboratory culture and/or surgery to replace the ovarian tissue back in the body is still necessary. Even though “auto-grafting” has resulted in a few pregnancies, this therapy is still in early development.
Although these technologies of fertility preservation are available, it is important to notice that there are no large randomized clinical trials to evaluate these interventions. There are no long-term follow up studies assessing the possible effect that these techniques may have on cancer survivors. To date, the available medical literature has demonstrated that pregnancy after cancer treatment does not trigger cancer recurrence, even in survivors of breast cancer. While chemotherapy can damage growing eggs and sperm, this damage generally disappears within 6 months to 2 years after therapy. Nonetheless, pregnancy after cancer can have some increased risks, such as maternal heart failure after certain types of chemotherapy. These pregnancies must be closely followed by a specialist in maternal fetal medicine.
In addition, birth defects in children born to cancer survivors are not any higher than in the general population (2-3%). No unusual risk for genetic diseases, such as Down syndrome and Turner syndrome, has been identified in the offspring of cancer survivors, neither has the risk of unusual cancers been identified in these children. Patients with inheritable diseases can have treatment with in vitro fertilization and pre-implantation genetic diagnosis to select for unaffected embryos for implantation into the uterus.