March 2011 Ask the Expert: Fertility and Pregnancy
During the month of March 2011, Living Beyond Breast Cancer expert Elizabeth S. Ginsburg, MD, answered your questions about how breast cancer treatments can affect your fertility and family planning, including how to coordinate treatment with your oncologist, methods of preserving fertility and timing treatments; the long-term effects of chemotherapy and how doctors can determine its impact on fertility; and post-treatment pregnancy and adoption options.
Dr. Ginsburg: There is only one paper looking at breast cancer recurrence in women undergoing IVF prior to breast cancer treatment in order to bank embryos for use after the cancer is gone. It is a relatively small study, but it showed no increase in recurrence risk 2 years after diagnosis. There are lots of studies looking at breast cancer recurrence in general, and that depends on factors related to the individual cancer’s characteristics.
Dr. Ginsburg: I suggest looking at the Sharing Hope Financial Assistance Program on the Fertile Hope website. The centers listed there offer discount services for patients with cancer who meet financial thresholds. You can cross reference them to their pregnancy rate data by looking at the Society for Assisted Reproductive Technology website and clicking on “ Find a Clinic.” Most centers who see many cancer patients are at academic centers or large private practices affiliated with cancer centers.
Dr. Ginsburg: Unfortunately the vast majority of women who get their periods back do so within a year after treatment. Tamoxifen generally won’t raise your FSH or anti-mullerian hormone (AMH) levels to menopausal levels, but tamoxifen may make you not have periods.
If you have had your FSH and estrogen level drawn only once, it may be worthwhile to repeat it or to have an AMH level drawn to confirm the results. If you already had some decrease in the number of eggs in your ovaries prior to having chemotherapy, this may be the reason why the chemo seems to have put you into menopause.
If you have many questions about this, I suggest asking your oncologist or OB/GYN for a consult with a reproductive endocrinologist.
Dr. Ginsburg: Tamoxifen won’t cause ovulation if you take it continuously. It does work like a medication called clomiphene citrate (Clomid, Serophen), but it’s taken for less than a week early in the menstrual cycle.
We don’t do IVF while women are on tamoxifen because the purpose of being on it is to keep the estrogen levels low, and the medications we use to stimulate egg development in the ovaries will raise the estrogen levels. You’d need to discuss with your oncologist whether it is possible to do an egg harvesting cycle while you are off tamoxifen prior to the 5-year mark. This is sometimes allowed, sometimes not, depending on the particular situation.
Dr. Ginsburg: There is no evidence that recurrence of breast cancer is higher during or after pregnancy for ER positive or negative breast cancer. There are, however, no randomized studies of this. It is possible that women who do become pregnant are in some way different than women who do not. In any case, the evidence is that if your oncologist says it’s OK for you to become pregnant, the risk of recurrence is not higher.
Dr. Ginsburg: It is tough to know that while on tamoxifen. A serum level of a factor called AMH may help determine the status of your ovarian reserve, i.e. if there are a reduced number of eggs in the ovaries. It is not common for someone your age to be permanently in menopause after chemotherapy for breast cancer.
Dr. Ginsburg: You should be able to breastfeed on the other side. Some oncologists prefer that patients not breastfeed, not because it causes breast cancer, but because it’s difficult to evaluate a breast for cancer when a woman is breastfeeding and for months afterward. This is because the breast becomes engorged and lumpy, and imaging studies and physical exams are not as effective.
Dr. Ginsburg: The general recommendation is 3 months.
Dr. Ginsburg: We know that virtually all women who receive dose-dense chemotherapy (or other combinations of chemotherapy that contain cyclophosphamide) have what we call decreased ovarian reserve, or fewer eggs left in their ovaries. That doesn’t necessarily mean that you’ll have difficulty conceiving, however.
Women who are 40 are more likely to have infertility than women who are in their 30s because of the reduced number of eggs remaining in their ovaries due to age, and also because older eggs are less likely to create normal embryos. Because abnormal embryos are much less likely to attach to the uterus and cause a pregnancy, chances of pregnancy are lower each month.
Decreased ovarian reserve doesn’t make the eggs less likely to fertilize or more abnormal, but it does mean that there are fewer expected years of fertility. When the egg pool is depleted, periods stop and menopause occurs. This means that age is at least as important as the fact that you had chemotherapy, since egg quality diminishes so much as women age.
Your likelihood of having infertility is probably higher than someone else your age due to the higher likelihood of you having fewer eggs as well as older eggs. With that said, until you try to become pregnant there’s no way of predicting if you’ll have an infertility problem or not.
Dr. Ginsburg: This is up to your oncologist. The type of cancer you had often predicts how strongly oncologists feel about you completing 5 years of treatment or not.
Because most breast cancers which do recur do so within 2 years, many oncologists want their patients to receive at least 2 years of tamoxifen.
Dr. Ginsburg: We typically suggest 3 months.
Dr. Ginsburg: We don't know if a woman is fertile unless she tries to become pregnant and is succesful. However, having periods means that you are potentially fertile.
Dr. Ginsburg: If this is an actual period from ovulation then it is possible. However some women, particularly those on tamoxifen, will have abnormal uterine bleeding after ovarian function has truly stopped and the ovaries have run out of eggs. In this case, you should be evaluated to determine why you had a period and to make sure there is not a problem with the lining of the uterus.