Certain chemotherapies can force the ovaries into retirement within a few months of treatment: This is medical menopause. Fifty percent of women younger than 35 who have CMF (Cytoxan, methotrexate, fluorouracil) chemotherapy go into menopause, as do about 80% of women 35-44 and nearly 100% of women over 45. With Adriamycin chemotherapy, the risk of permanent menopause is somewhat less for women under 40, but it is similar to that of CMF for women over 40. Occasionally, chemotherapy-induced menopause is only temporary.
Medicines can be used to temporarily stop the ovaries from making estrogen. Two of the most common ovarian shutdown medicines are:
- Zoladex (chemical name: goserelin)
- Lupron (chemical name: leuprolide)
Zoladex and Lupron are both luteinizing hormone-releasing hormone (LHRH) agonists. These medicines work by telling the brain to stop the ovaries from making estrogen. The medicines are given as injections once a month for several months or every few months. Once you stop taking the medicine, the ovaries begin functioning again. The time it takes for the ovaries to recover can vary from woman to woman.
Hot flashes can get worse when tamoxifen (or other anti-estrogen therapies) is added after chemotherapy. Although these drugs don't cause menopause, they can mimic some of the symptoms, which may then continue for some time.
If you were on hormone replacement therapy (HRT) and had to stop when you were diagnosed with breast cancer, you may experience a hybrid of natural and medical menopause. This kind of "cold turkey" is the result of a dramatic drop in estrogen.
It's important to know that while hormone replacement therapy (HRT) can ease menopausal symptoms, such as hot flashes and fatigue, current or recent past users of HRT have a higher risk of being diagnosed with breast cancer.
Before the link between HRT use and breast cancer risk was established, many postmenopausal women took HRT for many years to ease menopausal symptoms and to reduce bone loss. Since 2002, when research linked HRT and risk, the number of women taking HRT has dropped dramatically. Still, many women continue to use HRT to handle bothersome menopausal symptoms.
In addition to breast cancer treatments, other medical treatments can push you into menopause. If your ovaries are surgically removed, you will go into menopause overnight — this is surgical menopause. This can be a difficult way to enter menopause because it's so sudden.
Natural menopause is a fender bender, whereas medical or surgical menopause is like hitting a brick wall at sixty miles an hour.
Kutluk Oktay, M.D.