| Home | Genes may not determine breast, ovarian cancer risk posted 5-30-97 New research suggests that women with a genetic defect linked to breast and ovarian cancer may not be as likely to develop the diseases as scientists originally predicted. The potentially faulty genes, known as BRCA1 and BRCA2, were discovered in the early 1990s. Studies two years ago suggested that women who carry one of the genes face an 85-percent risk of developing breast cancer by age 70. However, a report in the May 20 issue of the New England Journal of Medicine says the risk is really 56 percent for those women. Overall, about 13 percent of U.S. women are expected to develop the disease. Previous reports cited a 40-percent risk of ovarian cancer associated with the genes. New studies put the risk at 16 percent. The national average is 1.6 percent. The findings cast serious doubts on the usefulness of a $2,000 blood test that thousands of women have already used since last fall to detect the presence of the genes. As many as 20 percent of the healthy women who tested positive opted to undergo a double mastectomy in hopes of preventing future cancer. The contradictory findings and the possibility that some surgeries may have been unnecessary are prompting many healthcare experts to warn against using relatively new genetic tests for everyday clinical practice. Elective surgery might be a reasonable choice for women who carry a defective gene and come from families in which breast cancer is prevalent, some experts argue. In these cases, the risks may still be much higher than 56 percent. In addition, according to a second study released May 20 by the Dana-Farber Cancer Institute in Boston, these high-risk women could gain an average of three to five years of life by surgically removing their breasts. The scientists who originally located and tracked BRCA1 say the new study results are faulty. They note researchers in the latest study relied on participants to remember family history, while earlier studies only counted breast cancer cases that had been medically documented. Related Stories Related Site
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