Black Cohosh and Hot Flashes
A new study has concluded that the herb black cohosh provides only moderate relief for women suffering from hot flashes related to breast cancer. Unfortunately, the results were almost identical to that of a placebo.
Historically, black cohosh was used for centuries by American Indian women to alleviate painful menstrual symptoms. Today, it is regularly prescribed in Germany and throughout Europe to alleviate menstrual pain as well as to minimize menopausal symptoms.
Hot flashes occur as a result of diminished function by the ovaries, which is a natural result of menopause. However, for breast cancer survivors, premature menopause can also result due to chemotherapy. These resultant hot flashes can be more severe and frequent than those experienced by other women.
Researchers believe that hot flashes are caused by hormone fluctuations affecting the hypothalamus, the area of the brain where temperature is controlled. Typically, decreased estrogen levels associated with menopause are the catalyst.
Hormone replacement therapy, often used to minimize hot flashes, is not recommended for many breast cancer patients because of concerns about estrogen's role in encouraging new cancer growth.
Writing in the Journal of Clinical Oncology, Dr. Judith Jacobson of Columbia University in New York and colleagues reported on their study of 85 breast cancer patients; half took two daily tablets of black cohosh and half took a placebo. The women kept diaries to record the frequency and severity of their hot flashes over a four-day period before the study began, and again at 30 days and 60 days.
Interestingly, the researchers found that the women in both groups reported a similar decline in hot flashes, heart palpitations, headaches and irritability during the study. "For breast cancer survivors, our data provide little evidence of either harm or benefit from using black cohosh to control hot flashes," they wrote.
However, they did concede that black cohosh, taken at higher doses or for more than two months, might have a discernible benefit over a placebo. But more studies were called for.
An earlier study published in the journal Lancet Oncology noted that few remedies appear to provide meaningful relief for breast cancer patients suffering from hot flashes.
Dr. Charles Loprinzi of the Mayo Clinic in Rochester, Minn. and colleagues analyzed a number of the most common treatments for alleviating hot flashes, including black cohosh, vitamin E, estrogen, soy, venlafaxine, and certain drugs primarily used for other purposes. Of this group, Venlafaxine appeared to be the most promising.
Interestingly, Loprinzi's team found that as many as 20 percent of women who are given a placebo to treat their hot flashes report at least some relief of their symptoms, although there is no apparent reason for this high "placebo effect."
In terms of black cohosh, the researchers determined that it did seem to have a moderating effect on hot flashes, but they cautioned that no definitive studies have been undertaken concerning its long-term use or potential side effects.
SOURCES:
Journal of Clinical Oncology, May 15, 2001; 19:2739-2745
The Lancet Oncology, April 2001; 2:199-204
The Mayo Clinic, Rochester, Minn. (http://www.mayo.edu)