Removing the healthy breasts of women with genetic mutations that often trigger breast cancer can save their lives, Dutch researchers found in the strongest study yet to show that the controversial strategy works.
In the study, none of the women who chose to undergo preventive, or prophylactic, mastectomies developed the often-deadly cancer. In a comparison group of women who also had the mutant genes and opted only for checkups, one-eighth got breast cancer and one died.
Scientists had questioned whether the approach prevents breast cancer because some breast tissue remains after surgery and the mutant genes are in every cell in the body.
"We can say to our patients that this method of prevention is nearly 100 percent effective and that they can sleep without fear of getting breast cancer," said Dr. Jan Klijn, chairman of the Rotterdam Family Cancer Clinic, part of Erasmus University Medical Center, where the research was done.
Other experts, however, cautioned that the women, many in their 20s and 30s, were followed for only three years on average.
The research is reported in today's New England Journal of Medicine.
From 1992 on, Klijn and colleagues studied 139 women after they were determined by DNA testing to have a dangerous mutation on either of the breast cancer susceptibility genes, BRCA1 and BRCA2. The mutations carry a lifetime breast cancer risk of up to 85 percent.
More than half of the women _ 76 _ chose to have a prophylactic mastectomy.