|
While it’s widely believed that black cohosh can relieve menopausal symptoms, especially hot flashes, findings from a study by a Duquesne pharmacy professor indicate that the herbal extract may cause cancerous cells to spread in women who have breast cancer.
“The study suggests that there would not be any increased risk of developing breast cancer if the woman was taking black cohosh before the tumor started to form. But, if there is a tumor, it may make it more likely to spread outside the breast to other organs,” explained Dr. Vicki Davis, assistant professor of pharmacology, whose research findings were published in the October issue of Cancer Research.
Funded by the Susan G. Komen Foundation, Davis’s research focused on the HER2+ type of breast cancer. The testing found that mice that were fed an adjusted dose of black cohosh to mimic a woman’s daily dose of 40 mg were 25 percent more likely to develop lung tumors compared to mice that did not take the herb.
“We have to consider the limits of the study, which is only studying one type of breast cancer, so the results may suggest black cohosh may only influence this type of cancer,” Davis pointed out. “We haven’t tested other tumor types to know if black cohosh would act similarly.”
According to Davis, the mice were also tested for long periods to ensure that they were exposed to black cohosh when tumors would begin to form. In contrast, Davis said that women only need to use the herb for a limited time while they are experiencing menopausal symptoms.
“Black cohosh may not exert the same effect if only used for a few months,” said Davis. “However, it is important to note that the dose tested was adjusted for the mice to correlate to the recommended dose for women. Therefore, the mice were not exposed to abnormally high levels to cause the increase metastatic cancer.”
Davis also clarified that black cohosh, which is not regulated by the U.S. Food and Drug Administration, is a complex product with numerous components that may have different effects on the breast and on cancer.“Therefore, to provide simple or direct recommendations is more difficult. The biggest concerns may be the use of black cohosh with breast cancer until more data are available to indicate its safety with different tumor types, treatment lengths, and in combination with other therapies,” she said. “Also, as some women increase the dose if their symptoms continue, higher doses could further enhance the effects observed in our study.”
When asked about other nonprescription alternatives that women may use to treat menopausal symptoms, Davis said there are no simple answers. “Unfortunately, there are limited options of over-the-counter and prescription drugs that have been fully investigated for their safety profile in regards to breast cancer or other cancer risks,” said Davis. “Studies on the effectiveness of different therapies for alleviating hot flashes and other symptoms that accompany the transition to menopause do not tell us if the therapy will modify the woman’s cancer risk. For women with minimal symptoms, no treatments may be necessary. But quality of life must be considered for women with hot flashes that are moderate to severe in balance with the potential risks.”
| 
