Menopause and Cancer Treatment

Nancy Peacock, M.D

Complete cessation of ovarian function for a period of at least one year is defined as menopause.  When ovarian function ceases, serum estradiol levels drop and serum FSH and LH levels rise.  The numeric value assigned to those levels isn't necessarily important because vasomotor symptoms and urogenital changes are well described and easily recognized.  Hot flashes, cold sweats, insomnia, leg cramps, joint stiffness, weigh gain, irritability (possibly related to all of the aforementioned) and vaginal dryness, often accompanied by a drop in libido, may occur in the absence of estrogen.  These symptoms aren't pleasant when, at the average age of 52, a woman eases into them.  However, they are devastating when someone with breast cancer has them thrust upon her in an attempt to achieve a therapeutic effect.

Yet, anti-estrogen therapy may be the most effective and least toxic of all our breast cancer treatment options.  So, let's review what is known about hormones and breast cancer:

  • The Nurses’ Health Study determined the combination of estrogen and progesterone in post menopausal women (used to alleviate menopausal symptoms) increases the risk of an unaffected woman developing invasive breast cancer.
  • Estrogen dependent breast cancer cell lines, grown in mice, display increased growth when exposed to added estrogen.  Recent clinical trials using drugs with estrogenic properties increase the risk of breast cancer recurrence in humans when used in women with localized disease. These findings have led most oncologists to believe that the use of estrogens is contraindicated in women who have had breast cancer, whether they are currently being treated or not.
  • Women with metastatic breast cancer will respond to pharmacologic interventions which block the cancer cells from estrogen.
  • Both pre and post menopausal women who express estrogen or progesterone receptors on their cancer cells have a decreased risk of recurrence of their cancer when anti-estrogen therapy is used.

Natural or bio-identical hormone replacement is not any safer than commercially available hormone preparations with respect to risk of occurrence or recurrence of breast cancer.  These agents are unregulated by the FDA and the amounts of active drug absorbed into the system that are not always predictable.  We don't know with any scientific certainty whether topical vaginal estrogen preparations are safe to use in women who are being treated or have been treated for breast cancer.

So, what should one do if faced with severe menopausal symptoms in the setting of a breast cancer diagnosis?  Talk to your physician.  There may be a specific treatment for a symptom you are experiencing.  Your doctor should be able to tell you the things we know with scientific certainty and those we don't know.  He or she can also talk with you about the risk you may be entertaining and the benefit you might derive should you choose certain therapies.

We have learned that lifestyle and behavioral changes that include an increased level of physical activity, a reduction in dietary fat intake to approximately 20% of daily calories and careful attention to hydration, calcium and vitamin D intake will help control hot flashes, improve sleep patterns, and may decrease some of the irritability and depressive mood swings menopausal women suffer from.