MONDAY, Nov. 17 (HealthDay News) -- Women who test negative for BRCA gene mutations but have a significant family history of breast cancer still have a fourfold risk of developing breast cancer, according to research presented at the American Association for Cancer Research Frontiers in Cancer Prevention Research conference held Nov. 16 to 19 in Washington, D.C.

Kelly Metcalfe, Ph.D., of the University of Toronto, Canada, and colleagues studied 1,492 women from 365 families with a history of two or more breast cancers cases under the age of 50 or with three cases of breast cancer at any age.

During 9,109 person years of follow-up, the researchers identified 65 cases of incident breast cancer compared to an expected number of 15.2 cases (standardized incidence ratio, 4.3). Although they found that the incidence was highest for women under age 40 (SIR, 14.9), they found that the absolute risk was higher among women aged 50 to 70 than among those aged 30 to 40 (1 percent per year versus 0.4 percent per year).

"Women in these families may be candidates for tamoxifen chemoprevention or intensified breast screening with MRI," the authors conclude.

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