Cancer and Female Infertility
Female Reproductive System
The organs of the female reproductive system produce and sustain the female sex cells (egg cells or ova), transport these cells to a site where they may be fertilized by sperm, provide a favorable environment for the developing fetus, move the fetus to the outside at the end of the development period, and produce the female sex hormones. The female reproductive system includes the ovaries, fallopian tubes, uterus, vagina, accessory glands, and external genital organs.
Surgical procedures that remove organs of the female genital and reproductive tract, such as a radical cystectomy (removal of the bladder, uterus, ovaries, falopian tubes, cervic, front wall of the vagina and the urethra), and bilateral oophorectomy (the removal of both ovaries) will result in permanent infertility. The removal of only a single ovary and tube, however, does not significantly affect fertility, and still allows for future pregnancy.
The removal of the uterus, but not the ovaries, will leave the possibility of biologic motherhood with the use of a surrogate gestational carrier. A surrogate gestational carrier is a woman who accepts the transfer of a fertilized egg (embryo) into her uterus. The embryo is created by the patient and the patient's partner. The patient with ovaries remaining must undergo ovarian stimulation, egg harvesting and in vitro fertilization (IVF) with her partner to produce an embryo. If the embryo successfully implants within the uterus of the carrier, and a pregnancy develops, the fetus has no biological relationship to the surrogate gestational carrier, but, rather, is the biologic child of the patient and her partner.
The effects of chemotherapy and radiation therapy on female fertility are dependent on many factors. The age of the female at the time of treatment, the particular chemotherapy agent, the location of radiation therapy, as well as total dose and duration of both radiation and chemotherapy treatment are important factors.
- Carmustine (BCNU)
- Lomustine (CCNU)
- Nitrogen Mustard
Chemotherapy is the broad term used to describe cancer treatment with dozens of drugs, but only certain chemotherapy agents are known to induce infertility. Not surprisingly, higher doses of the offending agent are more apt to cause problems. Combining different chemotherapy agents that may induce infertility can potentiate toxicity at a lower total dose. The class of drugs known as alkylating agents has been frequently implicated.
Radiation therapy delivered near the ovaries may result in permanent infertility. Radiation to the pelvis, abdomen or spine will usually include the ovaries and uterus within the treatment port. Total body irradiation (TBI), sometimes used in preparation for a bone marrow transplant, will always affect the ovaries. In contrast, radiation administered to areas above, or well below the pelvis has no effect on ovarian function. Similar to chemotherapy, sterilizing effects of radiation treatment are dependent on dose, delivery (fractionalization) schedule, and patient age at the time of treatment. Women over 40 at the time of treatment may have permanent ovarian failure induced with doses as low as 4 Gy. (Wallace Human repro 2003). Significantly higher doses are needed to induce ovarian failure in younger women and children.
In summary, it is difficult to predict who will develop ovarian failure at the time of cancer diagnosis. The likelihood of sterility is greater following treatment with ovarian radiation exposure greater than 3000 cGy, or following treatment with high cumulative doses of Cyclophosphamide or Busulfan. However, even women who receive high doses of therapy have become pregnant after therapy.