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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.

Are there any data on the levels of breast cancer recurrence following cancer treatment? The only studies that I have been able to find look at risks of breast cancer associated with IVF carried out prior to chemo, radiation, etc. or are broader studies that look at rates of cancer after IVF. Since I was unable to undergo IVF before my treatment for breast cancer, I would imagine that those sort of studies would underrepresent the risk for me. Is that correct?

What IVF treatment regimens are recommended for patients who have breast cancer (estrogen receptor-positive, stage II, HER2-positive), have undergone chemo and who have a low levels of AMH?

Which are the key centers of excellence on fertility and cancer?

I am 37 years old and was 35 at diagnosis. I had my last period as soon as I started chemo and now, over a year and a half out, have not started again. My doctor checked my hormones and determined that I was in menopause. Is the tamoxifen I am taking keeping my hormones shut off? Is there any chance that my system will turn back on?

I have been taking tamoxifen for almost two years after having completed surgery, chemotherapy and radiation. I understand tamoxifen is sometimes used as a fertility treatment, as it stimulates ovulation. Is it possible to harvest eggs while on tamoxifen (without taking any other fertility drug)? I want to complete the five years of tamoxifen, though I know that the age when the eggs are harvested is crucial to a successful pregnancy. I will be almost 40 when I complete my tamoxifen treatment.

Does pregnancy increase the risk of recurrence or a new primary tumor for someone with a history of ER positive breast cancer? Since estrogen levels rise steadily during pregnancy, will such a hormonal stimulation trigger cancer cell growth as well?

I am a 30-year-old, three-year breast cancer survivor. I am two years past chemo and almost two years into my five-year prescription of tamoxifen. I went through a forced menopause during chemo, but within a year of treatments I regained my period. However, for a number of months now I have not had a period, and I am wondering if that may be reflective of my fertility?

I am thinking of stopping tamoxifen early (i.e. after three years instead of five) in order to try to get pregnant. I am wondering about the risks and the option of restarting tamoxifen after pregnancy.

After a single mastectomy, I am wondering how breastfeeding may or may not work for me in the future.

How long before starting IVF should you stop taking tamoxifen?

Fertility was not discussed prior to eight rounds of dose-dense chemotherapy. I was 37 years old. I continued to have periods during chemotherapy, but I skipped two periods during my last doses of A/C. I am now 40. I am curious as to how the treatment impacted my ability to conceive.

I was diagnosed with stage IIb breast cancer and had a double mastectomy. I finished chemotherapy (FEC x3 followed by docetaxel x 3) in the fall then immediately started tamoxifen. My husband and I want to start a family soon, but for how long must I take tamoxifen before we can start? My oncologist said at least a year, but I have also read 2 years and up to 5 years?

How long after I stop taking tamoxifen can we start trying to have a baby?

I got my period back 5 months after my last chemotherapy, and they seem to come monthly now. Does that mean I am fertile? I am on tamoxifen.

I am almost a 4-year breast cancer survivor (diagnosed at 37 years old). I hadn't had a menstrual cycle since before I started chemo until today. To my surprise my cycle started, and I thought it was gone forever. I pretty much ruled out the chances of having at least one child. Do I still have a chance of conceiving?

Question: Are thereany data on the levels of breast cancer recurrence following cancer treatment? The only studies that I have been able to find look at risks of breast cancer associated with IVF carried out prior to chemo, radiation, etc. or are broader studies that look at rates of cancer after IVF. Since I was unable to undergo IVF before my treatment for breast cancer, I would imagine that those sort of studies would underrepresent the risk for me. Is that correct?

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.

Question: What IVF treatment regimens are recommended for patients who have breast cancer (estrogen receptor-positive, stage II, HER2-positive), have undergone chemo and who have a low levels of AMH?

Dr. Ginsburg: We use “poor responder” protocols which typically use high doses of stimulation medications, letrozole (Femara) to keep estrogen levels low and a gnRH antagonist. This is a fairly common protocol used in this setting.

Question: Which are the key centers of excellence on fertility and cancer?

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.

Question: I am 37 years old and was 35 at diagnosis. I had my last period as soon as I started chemo and now, over a year and a half out, have not started again. My doctor checked my hormones and determined that I was in menopause. Is the tamoxifen I am taking keeping my hormones shut off? Is there any chance that my system will turn back on?

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.

Question: I have been taking tamoxifen for almost two years after having completed surgery, chemotherapy and radiation. I understand tamoxifen is sometimes used as a fertility treatment, as it stimulates ovulation. Is it possible to harvest eggs while on tamoxifen (without taking any other fertility drug)? I want to complete the five years of tamoxifen, though I know that the age when the eggs are harvested is crucial to a successful pregnancy. I will be almost 40 when I complete my tamoxifen treatment.

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.

Question: Does pregnancy increase the risk of recurrence or a new primary tumor for someone with a history of ER positive breast cancer? Since estrogen levels rise steadily during pregnancy, will such a hormonal stimulation trigger cancer cell growth as well?

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.

Question: I am a 30-year-old, three-year breast cancer survivor. I am two years past chemo and almost two years into my five-year prescription of tamoxifen. I went through a forced menopause during chemo, but within a year of treatments I regained my period. However, for a number of months now I have not had a period, and I am wondering if that may be reflective of my fertility?

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.

Question: I am thinking of stopping tamoxifen early (i.e. after three years instead of five) in order to try to get pregnant. I am wondering about the risks and the option of restarting tamoxifen after pregnancy.

Dr. Ginsburg: You will need to discuss this with your oncologist. I am not aware of any data evaluating whether that will help reduce your risk of recurrence.

Question: After a single mastectomy, I am wondering how breastfeeding may or may not work for me in the future.

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.

Question: How long before starting IVF should you stop taking tamoxifen?

Dr. Ginsburg: The general recommendation is 3 months.

Question: Fertility was not discussed prior to eight rounds of dose-dense chemotherapy. I was 37 years old. I continued to have periods during chemotherapy, but I skipped two periods during my last doses of A/C. I am now 40. I am curious as to how the treatment impacted my ability to conceive.

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.

Question: I was diagnosed with stage IIb breast cancer and had a double mastectomy. I finished chemotherapy (FEC x3 followed by docetaxel x 3) in the fall then immediately started tamoxifen. My husband and I want to start a family soon, but for how long must I take tamoxifen before we can start? My oncologist said at least a year, but I have also read 2 years and up to 5 years?

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.

Question: How long after I stop taking tamoxifen can we start trying to have a baby?

Dr. Ginsburg: We typically suggest 3 months.

Question: I got my period back 5 months after my last chemotherapy, and they seem to come monthly now. Does that mean I am fertile? I am on tamoxifen.

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.

Question: I am almost a 4-year breast cancer survivor (diagnosed at 37 years old). I hadn't had a menstrual cycle since before I started chemo until today. To my surprise my cycle started, and I thought it was gone forever. I pretty much ruled out the chances of having at least one child. Do I still have a chance of conceiving?

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.

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