RACIAL-DIFFERENCES IN SURVIVAL FROM BREAST-CANCER - RESULTS OF THE NATIONAL-CANCER-INSTITUTE BLACK WHITE CANCER SURVIVAL STUDY/

Objective.-To examine the ability of recognized prognostic factors for breast cancer to account for the observed poorer survival in blacks c ompared with their white counterparts. Design and Participants.-Subjec ts included 1130 women (612 blacks and 518 whites) aged 20 to 79 years residing in metropolitan Atlanta, Ga, New Orleans, La, or San Francis co/Oakland, Calif, who were diagnosed with primary invasive breast can cer. Information on stage, tumor characteristics, treatment, comorbid conditions, and sociodemographic factors was obtained from personal in terview, physician and hospital records, and a pathology review of bio psy and surgical specimens. Main Outcome Measure.-Multivariable surviv al models were used to estimate the hazard ratio (relative risk of mor tality) for blacks compared with whites, adjusting for various combina tions of potential explanatory factors. Results.-After controlling for geographic site and age, the risk of dying was 2.2 times (95% confide nce interval [CI], 1.8 to 2.8) greater for blacks than whites. Adjustm ent for stage reduced the risk from 2.2 to 1.7; further adjustment for sociodemographic variables had no effect. Treatment was not a contrib uting factor once stage and tumor pathology were in the model. After a djusting for stage, treatment, comorbid illness, and pathologic and so ciodemographic variables, blacks continued to demonstrate a slightly i ncreased, but not statistically significant, risk of death (hazard rat io=1.3; 95% CI, 1.0 to 1.8). Results were similar for all-cause mortal ity and breast cancer-specific mortality. Conclusions.-Approximately 7 5% of the racial difference in survival was explained by the prognosti c factors studied. Sociodemographic variables appeared to act largely through racial differences in stage at diagnosis, which may be amenabl e to change through improved access to and use of screening for black women.