Radiation and chemotherapy treatment for cancer can cause infertility in both men and women. High doses of radiation and alkylating chemotherapy (such as chlorambucil, cyclophosphamide, and nitrogen mustard) pose the highest risk of damaging egg and sperm. However, some people suffer no fertility effects. Generally, the higher the dose and the longer the treatment, the greater the risk to your fertility.¹

Men

Whenever possible, men are advised to have some of their sperm frozen (cryopreserved) in a sperm bank before cancer treatment. If you have had cancer treatment in the past and have very low sperm counts, you may be able to father a child using assisted reproductive technologies called intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF). In these, sperm are collected then injected into your partner's egg, grown in the laboratory for a few days, then transferred into her uterus. ICSI and IVF can also help you conceive if you have no sperm in your semen.¹ It is possible that you still have immature, healthy sperm in your testicles, which can be found and surgically removed through a small incision (testicular biopsy), then used for ICSI.

Men who have low or no sperm count after cancer treatment may gradually improve over a period of years.²

A small study has suggested that post-cancer-treatment sperm generally have healthy DNA.²

Women

Eggs don't survive cryopreservation as well as sperm do, so fertility-preserving treatment options are more complicated and/or experimental for women than for men. They include:

• Delaying cancer treatment for a month or more, and using in vitro fertilization (IVF) to produce fertilized eggs (embryos or blastocysts) that can be frozen for use in the future. IVF is only an option, however, for women who don't have a type of cancer that is stimulated by estrogen—high estrogen levels are necessary to stimulate egg production before harvesting them for IVF.
• Having all or part of an ovary surgically removed and frozen. Early research has shown that when strips of thawed ovarian tissue are re-implanted in the body after treatment, they can produce eggs for in vitro fertilization.³ Some infertility clinics will cryopreserve ovarian tissue for women who hope to use this experimental procedure after cancer treatment, should it become available in the future.
• Surgical placement of ovaries outside the radiation-affected area of the body.
• "Shutting down" the pituitary with a gonadotropin-releasing hormone agonist (GnRH-a) during chemotherapy to protect the egg supply. One small study of 34 women has suggested that this experimental treatment improved the chances that a woman would resume ovulating 3 to 8 months after chemotherapy.³ (The same effects may not be seen for women receiving high-dose chemotherapy before a bone marrow transplant.)