- Question from Zoe: I am a 30-year-old woman just diagnosed with breast cancer Stage 2, estrogen-positive. If I was to go through chemotherapy, what is the likelihood of my fertility being compromised?
Kutluk Oktay, M.D.
This is going to depend on the combination therapy that you will receive. In general, the combination that involves CMF (Cytoxan, methotrexate, 5-Fluorouracil) tends to have a higher rate of ovarian failure and infertility compared to AC chemotherapy (Adriamycin and Cytoxan, with or without a taxane). For a 40-year-old woman, the likelihood of infertility within one year of chemotherapy is about 80%, whereas for the AC combination, it's about 40%. So the incidence doubles if you get CMF.
For a 30-year-old, this would be lower. But resumption of menstruation is not necessarily a good way to assess if you remain fertile, because regardless of the combination, the CMF results in significant damage to your eggs. If you're younger, you have a larger number of eggs, so you can tolerate it a lot better than an older woman. But that still doesn't mean you'll be fertile, even if you continues to menstruate.
Women are born with all the eggs in their ovaries that can mature and potentially be fertilized throughout their lives. The eggs that aren't mature yet and are waiting to grow are called reserve eggs, or primordial eggs. These are different from the eggs you can see on an ultrasound, the eggs that make hormones and are ready to be fertilized. The reserve eggs you can't see on an ultrasound. But they determine when a woman will go into menopause.
If the number of the reserve eggs has gone down because of chemotherapy, then the menopause will occur sooner. Chemo damage is done to the eggs, not the surrounding cells. These cells can be replaced, but the eggs cannot be replaced. So once the damage is done, there's no going back.
- Marisa Weiss, M.D. Is there anything a woman can do to protect her reserve eggs from the effects of chemo, besides choosing a chemotherapy regimen that is likely to be effective against the cancer and safer towards the ovaries?
Kutluk Oktay, M.D.
The primordial eggs are inert and do not respond to hormones. They don't need hormones, and we don't clearly know what makes them mature. Much has been debated about using drugs to put women into temporary menopause during chemotherapy. These drugs are called gonadotropin-releasing hormone agonists (for example, Lupron or Zoladex). However, the scientific evidence for their benefit is lacking.
What these drugs do is lower hormone levels, specifically one called Follicle Stimulating Hormone (FSH). However, since primordial eggs don't have a receptor for these hormones, the benefit of lowering these hormones is highly unlikely. We don't have any solid studies on this. So we don't have a proven medical treatment to protect ovaries from the effects of chemotherapy that we can trust.
- Marisa Weiss, M.D. So what is a woman to do who wants to maximize her chance of eventually having a baby?
- Kutluk Oktay, M.D. There are several strategies to preserve fertility. In other cancer types, there isn't enough time to utilize one of several assisted reproductive techniques to preserve fertility. But in breast cancer, there is usually a four-to-six week recess, or pause, between surgery and chemotherapy, which can make it possible to use some of the technologies that involve harvesting eggs and freezing embryos.
On Wednesday, August 18, 2004, our Ask-the-Expert Online Conference was called Pregnancy and Fertility Issues. Kutluk Oktay, M.D., Leslie Schover, Ph.D., and moderator Marisa Weiss, M.D. answered your questions about pregnancy and fertility before, during, and after breast cancer treatment, as well as the options of adoption and gestational carriers (surrogate mothers).
The materials presented in these conferences do not necessarily reflect the views of Breastcancer.org. A qualified healthcare professional should be consulted before using any therapeutic product or regimen discussed. All readers should verify all information and data before employing any therapies described here.
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