Abstract P5-12-07: Triple-negative breast cancer in African American women - How women in New Orleans compare to the rest of Louisiana and the Nation

Abstract

Abstract Background: For years clinicians have made the empirical observation that there is an unusually high number of African American women (AAW) with triple-negative (Tneg) breast cancer (BC) in New Orleans (NO). Knowing the rate of Tneg BC in AAW is higher than white women (WW), we explored the hypothesis that AAW in NO have a higher rate of Tneg BC when compared to AAW in the rest of Louisiana (LA) and the US. Methods: We analyzed data from the Louisiana Tumor Registry, one of the NCI funded SEER registries, for the tumor characteristics of invasive female BC diagnosed in 2010, focusing on racial disparities; HER2 status was not available prior to 2010. We explored the association of HER2 status with age, race, ER, PR, T, N and M status to determine crude and adjusted odds ratios and rate distribution of subtypes using SEER*Stat and SAS programs. With the recent release of SEER 18 data including HER2 status in cases diagnosed in 2010 we also looked at national rates of Tneg BC in WW compared to AAW and compared these findings to NO and LA. Results: Overall age-adjusted incidence rate of Tneg BC in AAW was 34.0 per 100,000 in NO, 27.2 per 100,000 in AAW in the rest of LA and 20.4 per 100,000 in SEER 18. This translates into a statistically significant increase in incidence rates of Tneg BC in AAW in NO by 67% (p = < 0.05) compared to SEER 18. The rates in WW were 11.3 per 100,000 in all 3 locations. AAW with Tneg BC in NO were more likely to have more aggressive BC. Young age, black race, large tumor size, higher grade and TNM stage were significantly associated with the high risk of Tneg BC. After adjusting for age, geographic area, and other tumor characteristics, the higher risk of Tneg BC in AAW remained in NO compared with the rest of LA and locations of the SEER 18 registries. Table 1: 2010 Tneg rates per 100,000 in NO, LA and SEER 18 RateCountRate RatioRate Lower CIRate Upper CIWhiteSEER 1811.33884154 LA11.30512000.99700.85731.1543 NO11.2441320.99160.66501.4340BlackSEER 1820.39961094 LA27.18622041.33271.13841.5534 NO34.0092611.66721.25822.1711 Conclusions: The incidence rates of Tneg BC in AAW in NO and LA are significantly higher than in SEER 18, with rates in NO being the highest. Rates of Tneg BC in WW in all data sets were similar. SEER 18 analysis also confirms a higher incidence of Tneg BC in AAW compared with WW as previously reported in smaller case series. AAW in NO are more likely to have poorly differentiated and Tneg BC compared to AAW in the rest of LA. This newly identified disparity in the AAW population in NO has clinical implications and translational research potential as it enables us to broaden the understanding and treatment of this aggressive disease. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-12-07.