Goals of work: Black cohosh is commonly used to treat hot flashes and other symptoms associated with menopause. It is thought to have multiple mechanisms of action, including potential phytoestrogenic properties. This has caused some concern about its use by patients with hormone-sensitive cancer. This paper will present the results of a systematic review of the safety and efficacy of black cohosh (Cimicifuga racemosa [L.] Nutt.) in patients with cancer.
Materials and methods: A critical assessment of clinical (n = 5) and preclinical (n = 21) studies of black cohosh and cancer (breast and prostate) to treat hot flashes and other related symptoms is presented. In addition, clinical studies, case reports, animal studies, and in vitro assessments of the safety of black cohosh for patients with hormonally sensitive cancers is summarized and interpreted.
Main results: In general, the research assessing efficacy of black cohosh for the treatment of hot flashes in women with breast cancer is inconclusive. There is laboratory evidence of antiproliferative properties but no confirmation from clinical studies for a protective role in cancer prevention. Black cohosh seems to have a relatively good safety profile. Concerns about liver toxicity are inconclusive. With relevance to cancer patients, black cohosh also seems not to exhibit phytoestrogenic activity and is in fact possibly an inhibitor of tumor growth.
Conclusions: The use of black cohosh appears to be safe in breast cancer patients without risk for liver disease, although further research is needed in this and other populations.