Efficacy and safety of black cohosh in women with breast cancer

Many women use black cohosh as a natural treatment for menopausal symptoms. However, controversy exists around safety in breast cancer, because of its purported estrogenic activity. The purpose of study was to review and summarise current evidence on the efficacy and safety of herbal medicinal products for the relief of hot flushes in women with previous breast cancer. It is also called black snakeroot, macrotys, bugbane, bugwort, rattleroot, rattleweed, rattlesnake root or squawroot. We searched MEDLINE, Embase, the Cochrane Library, and AMED from inception to May 2016 and for human interventional or observational data pertaining to the safety and efficacy of black cohosh in patients with or at risk of breast cancer, including an assessment of the effect of black cohosh on estrogen responsive tissues. Black cohosh, an herb most commonly used to reduce menopausal symptoms such as hot flashes, may stop breast cancer cells in their tracks. This adds more evidence to a small but growing body of research suggesting that black cohosh could have a use in breast cancer prevention. Black cohosh and phytoestrogens have received the most research attention but there is currently insufficient evidence to recommend either for relief of flushes. Opposing advice has been given regarding the safety of dietary phytoestrogen use for women with previous breast cancer, but there is emerging data that soyfood phytoestrogen intake may have a beneficial effect on tumour recurrence. It has also, effects on prostate cancer cells in the laboratory and in animal studies. Current evidence does not support an association between black cohosh and increased risk of breast cancer. There is a lack of evidence supporting the efficacy of black cohosh for reduction of hot flashes in breast cancer patients. Given conflicting but promising results, and apparent safety, further research is warranted.

Keywords:

Black cohosh , Breast neoplasm , Estrogen , Herb–drug interactions , Phytoestrogen