Simplified model predicts estrogen receptor-positive breast cancer risk

November 21, 2007

NEW YORK (Reuters Health) - A simplified model that includes age, breast cancer in first-degree relatives, and previous breast biopsy examination identifies women at risk for estrogen receptor (ER)-positive (but not ER-negative) breast cancers, according to a report in the November 21st Journal of the National Cancer Institute.

"Few MDs are doing breast cancer risk assessment at the present time since they think it is too cumbersome to attempt a computer analysis in a busy visit," Dr. Rowan T. Chlebowski from Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California told Reuters Health. "The approach with this new model takes almost no time at all, and I hope MDs would consider its use."

Dr. Chlebowski and associates evaluated and attempted to improve the performance of the Breast Cancer Risk Assessment Tool (i.e., the Gail model) for estimating invasive breast cancer risk by receptor status in postmenopausal women.

The Gail model 5-year risk estimate underestimated the number of breast cancers diagnosed within 5 years by about 20%, the authors report.

For women with ER-positive tumors, the simplified model showed only small and insignificant differences with the Gail model at the estimated 1.8% probability threshold often used to identify women who would benefit from risk reduction interventions.

Using the simplified model, all women older than 55 years with either a previous biopsy examination or a first-degree relative with breast cancer had a 5-year risk of invasive breast cancer greater than 1.8%, the investigators say.

Among African American women, those 60 years of age or older with a previous biopsy examination and a positive family history of breast cancer had a 5-year risk greater than 1.8%.

"The model lends itself to a very simple use in clinical practice," Dr. Chlebowski said. "Ask women 55 years of age or older if their mother, sister, or daughter had breast cancer or if they had a breast biopsy at any time. If the answer is yes to either, the woman may be a candidate for a preventive intervention discussion regarding raloxifene or tamoxifen."

"(The authors) have presented useful and important results that illustrate the promise and difficulty of estimating absolute risk in subtypes of breast cancer," write Dr. Mitchell H. Gail and colleagues from National Cancer Institute, Bethesda, Maryland in a related editorial. "Additional studies of this type are needed in women aged 50 years or older and in younger women."