A woman is born with all of her eggs; she cannot produce more. Over time and with each menstruation, her egg supply decreases until the ovaries are empty and menopause begins.
Cancer itself can reduce fertility. However, this is only true for cancers that affect the reproductive organs, such as cancer of the uterus. Other cancers may not directly cause infertility. In most cases, infertility is actually caused by the treatment for the cancer, such as chemotherapy or radiation, rather than the cancer itself.
Chemotherapy is designed to kill rapidly dividing cells throughout the body. Cancer cells divide rapidly, but so do the cells surrounding the ripening eggs in women’s ovaries. Thus, infertility is a potential side effect of chemotherapy. Likewise, radiation therapy also kills rapidly dividing cells, but only in or around its target area. If the radiation field includes the brain, it may affect fertility by damaging areas that control hormone production. Radiation therapy aimed close to or at the pelvic area can also cause infertility by directly damaging the ovaries. Surgery to remove part or all of the reproductive system can lead to infertility as well.
Female fertility can be affected in two ways. First, you may not regain your menstrual cycle after cancer treatment. If your period is going to return, it usually takes six months to one year. Secondly and more commonly, even if you regain your menstrual cycle, you may be at risk for premature ovarian insufficiency. Premature ovarian insufficiency means that your body enters menopause prematurely. (The average age of menopause is about age 50).
A common assumption is that when a woman is diagnosed with cancer it is essential that her treatment begin immediately. For common types of cancers observed in young women, some oncologists may be comfortable with delaying treatment two to three weeks to allow time for emergency in vitro fertilization and egg harvests to be performed.
Eggs, embryos and ovarian tissue can be frozen indefinitely. Damage occurs at the time of freezing and thawing, so once frozen they can remain frozen for many years. There are case reports of patients who have had embryos frozen for more than 10 years and have still gone on to achieve pregnancy.
Women may consider going through emergency in vitro fertilization using donor sperm to create embryos to be frozen and stored for later use. You can find donor sperm at sperm banks. Although still considered somewhat experimental, it is also possible to undergo egg retrieval, and freeze the eggs rather than create embryos. Another option is to have ovarian tissue removed and frozen, a process called ovarian tissue cryopreservation.
There are ways your oncologist can protect your fertility during surgery or during cancer treatment. They are:
Before radiation therapy, the oncologist evaluates the potential effect of the therapy on normal tissues that are near the cancer. The doctor determines the optimal area to treat, and whether normal tissues or highly sensitive tissues, such as the ovaries, can be shielded to reduce the amount of radiation exposure. This is standard practice at most radiation therapy facilities.
The oncologist also determines the dose of radiation needed to kill the cancer while minimizing the toxic effect on nearby normal and sensitive tissues. This is also standard practice at most radiation treatment facilities.
Surgeons can move the ovaries away from the area receiving radiation therapy. The goal of the surgery is to move the ovaries within the pelvis where they can still function, but out of the way of harmful radiation. Recovery times vary, but on average, recovery takes between two days and two weeks. Most people who were healthy prior to their diagnosis are able to begin cancer treatment within the two-week recovery time, a timeframe that generally acceptable to oncologists.
Although your doctor can take certain measures to protect you, it is important to take charge of your own fertility. Patients are the best advocates for their own health. Make sure to discuss how your cancer and your treatment will affect your fertility.
It may be helpful to ask your oncologist these questions:
- Will my cancer treatments affect my fertility?
- Are there alternative ways to treat my cancer without compromising my fertility?
- What are my fertility preservation options?
- How much time do I have to preserve my fertility before I need to start my cancer treatments?
- Are premature ovarian failure or hormone deficiencies possible side effects of my treatment? If so, how do I treat them?
- Is pregnancy safe for me after treatment?
- What are the risks to future children based on my cancer and the treatment I receive?
- Can you refer me to a reproductive endocrinologist?
To date, there is no evidence that hormonal changes induced as part of the egg-harvesting process makes a woman’s breast cancer worse or more difficult to cure. But some doctors still have a concern because of the known association between estrogen and the development of breast cancer. However, experts in the field of oncofertility have concluded that if such a risk does exist, it is very minimal and they still recommend that patients with breast cancer undergo fertility preservation methods such as as embryo or egg freezing.
If your menstrual cycle returns, it usually takes six months to a year, and occasionally longer. If your cycle has not returned or is very irregular more than a year after treatment, you may want to consider fertility testing.
Many women resume menstruation after cancer and are fertile. Others resume menstruation and are infertile. It is important to remember that while producing and releasing normal eggs is an essential component of fertility potential, other abnormal conditions, such as hormone imbalances, can lead to infertility. Also, although you may regain your menstrual cycle after treatment, you may enter menopause prematurely, shortening the time span for natural conception.
Most patients are told to wait two years. The suggested timeframe is provided for several reasons. First, most cancers come back in the first two years. Second, eggs exposed to chemotherapy and/or radiation may suffer genetic damage. This damage is believed to repair itself within six months. Each person’s situation is different. It is important to consult with your medical team to determine your individual circumstances before trying to conceive.
Traditionally, blood tests to measure thyroid-stimulating hormone levels have been very helpful in looking at how well an adult woman’s ovaries are working and thus measuring her fertility.
However, many new cancer drugs are being used for young adults. The long-term effects of these drugs, including their effects on fertility, have not been determined. Therefore, we don’t have a clear-cut answer on how to measure the fertility of a woman who has had cancer and/or undergone cancer treatment.
Researchers are trying to determine how ultrasounds and blood tests are affected by cancer treatment. This information can help doctors develop techniques to accurately measure a woman’s fertility after cancer treatment.
Research in this area is limited, but reassuring. Current available research suggests that pregnancy after cancer does not cause or increase the risk of recurrence, even after breast cancer.