Abstract P3-09-01: Odds of the triple negative subtype and survival of stages 1–3 breast cancer: Variation by race/ethnicity

Background: Triple negative (TN) breast cancer is known to be more common in black and Hispanic women and associated with poor survival. This study assesses the differences in the odds and survival of the TN versus the ER+/PR+/HER2− (the most common subtype) by race/ethnicity separately for AJCC stages 1, 2, and 3. Methods: Using the California Cancer Registry for years 2000–2010, we examined 91,393 cases of stages 1–3 TN and ER+/PR+/HER2− first primary female invasive breast cancer. Race/ethnicity was defined as white, black, Hispanic, and Asian/Pacific Islander (API). Logistic regression was used to assess the association of race with odds of the TN subtype. Kaplan-Meier was used to compute 6-year survival. Cox proportional hazards was used to assess the risk of mortality of the TN subtype by race adjusting for age, grade, year of diagnosis, and socioeconomic status. All analyses were run separately for stages 1, 2, and 3. Results: The table shows the distribution of the TN and ER+/PR+/HER2-subtypes by stage and race/ethnicity. Blacks had increased odds of the TN compared with whites for stages 1 (OR = 2.24; 95%CI=1.96–2.56); 2 (OR = 2.01; 95%CI=1.81–2.25) and 3 (OR = 2.00; 95%CI=1.66–2.40). Hispanics had increased odds for the TN in stages 1 (OR = 1.23; 95%CI=1.11–1.35) and 2(OR = 1.20; 95%CI=1.11–1.31). APIs had decreased odds of the TN in stages 2 (OR = 0.85; 95%CI=0.77–0.93) and 3 (OR = 0.77; 95%CI=0.64–0.92). KM survival showed that APIs had the best 72 month survival for the TN in stages 1 (86%), 2 (78%), and 3(59%). Hazard ratios (HRs) indicated that all races with TN had the same risk of mortality in stage 1. Only in stage 2 did blacks have an increased risk of mortality (HR = 1.17; 95%CI=1.02–1.36) while APIs had a decreased risk (HR = 0.78; 95%CI=0.65–0.94). In stage 3, Hispanics (HR = 0.85; 95%CI=0.72–0.99) and APIs (HR = 0.70; 95%CI=0.55–0.89) had decreased risk of mortality compared with whites. Conclusions: Race/ethnicity is an important factor for survival of the TN subtype: 1. Although blacks and Hispanics are more likely to have the TN subtype, blacks have an increased risk of mortality compared with whites only in stage 2. 2. For stage 1, all races have the same risk of mortality. 3. Hispanics have decreased risk of mortality in stage 3. 4. APIs have decreased risk of mortality in both stages 2 and 3. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-09-01.