Predicting risk of developing invasive breast cancer in the African American female population

11080 Background: African Americans (AA) have a lower incidence of breast cancer with a poorer prognosis than Caucasians. It is unclear whether AA women have fewer known risk factors for breast cancer or that risk factors have a lesser effect in AA. We evaluated the accuracy of the race-based modification Gail Model in predicting the risk of developing invasive breast cancer in the AA population. Methods: With IRB approval, we performed a retrospective analysis of data obtained from women (n=15,973) ages 40–79 presenting to our Breast Center(5/2003 to 7/2005) for a screening mammogram. The five-year probability of breast cancer for AA (n=702) versus Caucasians (n=15,721) was calculated for each individual using 3 methods: 1) the race specific Gail model, 2) the Gail model ignoring race (AA using the Caucasian model), and 3) age and race matched SEER projection using DevCan (v6.1.1) software. Results: There was no significant difference between the 5-year probability of breast cancer for Caucasians as calculated by the Gail model vs. the SEER prediction (p=NS), suggesting our population was representative of the larger study population from which SEER data was derived. As compared to SEER prediction, the modified Gail model underestimated the breast cancer risk for all age groups of AA (p<0.0001). When the Gail Model without the race-based modification was applied to the AA population, the projected risk was not significantly different from the SEER prediction (p=0.1049). Conclusions: This study suggests that the race-based modification of the Gail Model underestimate the risk of breast cancer in AA women. When the model is applied to AA women without incorporating the modification for race, the Gail model accurately reflects SEER 5-year projections of risk of invasive cancer in AA women. Differences in risk factor distribution among race, rather than a differential effect of those factors on risk, may have a substantial role in explaining the lower incidence in AA women as compared to Caucasian women over 40. [Table: see text] No significant financial relationships to disclose.