Wednesday Bubble: herbs and breast cancer

Can herbal medicines used for hot flashes, namely black cohosh and phytoestrogens, be safely used in women who’ve had breast cancer?

If you’ve had breast cancer, you’ve probably been told to stay away from herbal medications, right? Yet, women who’ve had breast cancer know that hot flashes are a common side effect of many cancer therapies. Research also suggests that the older a woman is at the time she receives chemotherapy, the more likely she is to develop menopause as soon as treatment stops. Moreover, roughly 80% of women taking Tamoxifen have hot flashes and about a third of those women rate them as severe. Hormones are not even an option due to the increased breast cancer risk.

The good news is that an extensive analysis of scientific studies shows that black cohosh might be safe for women who have had breast cancer. Although the researchers note that the evidence for the effectiveness of black cohosh for alleviating hot flashes is mixed, they cite research from the National Institutes of Health and other reviews that suggest that use of black cohosh in former breast cancer patients requires only standard screening. They also report that there is “little reason for excluding patients with estrogen-responsive tumors from using black cohosh.” In fact, recent laboratory studies, although not yet carried out in humans, suggest that black cohosh may actually protect the breast from developing tumors.

The case for or against the use of phytoestrogens (e.g. soy, red clover, chaste tree berry and flaxseed) in women with breast cancer is not quite as clear as it appears to be for black cohosh. In one of the largest reviews examining soy or red clover for menopausal symptoms, the outcomes were equivalent to placebo. Other studies have shown that they might be beneficial for women with mild to moderate symptoms who start menopause early.  Moreover, while red clover in particular does not appear to affect certain breast cancer risk markers, reports about phytoestrogens in general, especially in estrogen positive cancers is conflicting. Still, the American Cancer Society does not advise against eating soy-rich foods by women who’ve had breast cancer. Some studies have also showed improved prognosis.

If you are wondering if there are any drawbacks, one of the largest challenges is that there are not that many studies looking at herbal medications in women with breast cancer and the ones that do exist are mostly short in duration. The researchers point out that because herbs can take awhile to work, a three month study might be too short to form a conclusion.

Clearly, more study is needed. In the interim, it appears both black cohosh and soy might be safe to try if you’ve had breast cancer. As always, the most important consideration is to speak to a certified practitioner who is well versed in herbal medicine and make sure that she or he works with your oncologist.