A new study assessing the use of hormone replacement therapy among breast cancer survivors has been stopped early because results indicate an unacceptably high rate of recurring or new cancers.
Swedish researchers embarked on the study in part because more women are surviving the disease and therefore subject to the same menopausal symptoms as other women. The study was expected to involve around 1,300 women over five years. After the initial 345 women in the study were followed for about two years, however, results showed 26 of those randomized to receive HRT experienced a new or recurring cancer, compared to just seven in a placebo group. The risk was deemed unacceptable, and the study was halted on December 17, 2003.
Noting some doctors prescribe HRT for their breast cancer patients with severe menopausal symptoms because observational studies have suggested no harm from the treatment, Harmon J. Eyre, M.D., chief medical officer of the American Cancer Society, comments, “This study will no doubt change that. It is large enough and clear enough to show that HRT appears to increase the chance of a new or recurring breast cancer. Because of that, offering HRT to women with a history of breast cancer would be unwise.”
In an accompanying commentary to the study, Rowan T. Chlebowski, from Harbor-UCLA Research and Education Institute in Torrance, Calif., and Nananda Col, from Brigham and Women’s Health Hospital in Boston, Mass., agree, noting, “Alternative safe and effective strategies for the difficult problem of menopausal symptoms in these women now need to be developed.”