Breast cancer patients who take estrogen do not appear to increase their risk of additional tumors, according to doctors who reviewed studies on the subject.
Most women who are found to have breast cancer get chemotherapy, which hastens menopause. But doctors commonly withhold estrogen, which could ease the discomfort of menopause, for fear that the hormone could reactivate the cancer.
However, a review of studies on the subject found no evidence that estrogen promotes additional breast tumors, and any possible risk may be outweighed by estrogen's benefits, said Dr. Melody Cobleigh, director of the Comprehensive Breast Center at Rush-Presbyterian-St. Luke's Medical Center in Chicago.
Cobleigh led the review for the Eastern Cooperative Oncology Group, 4,000 doctors who perform cancer research. The report was published in Wednesday's Journal of the American Medical Assn.
The review looked at whether evidence exists that hormone replacement therapy might reactivate dormant cancer cells; promote tumors in women who are known to be prone to them, or make cancer harder to detect on mammograms by making healthy breast tissue denser.