Racial differences in breast cancer survival: The effect of residual disease

Background. A survival difference has been seen in numerous studies between African-American (AA) and Caucasian (C) women with breast cancer. The purpose of this study was to elucidate the differences in patient characteristics and outcomes between AA and C women with breast cancer in our population. Methods. We performed a retrospective analysis of 1345 women with newly diagnosed breast cancer who were entered into our tumor registry from October 1980 to December 1998. Results. The association between race and stage at presentation was significant, as was the difference in the overall median survival between C and AA women. The data revealed no significant differences in survival between C and AA women presenting with Stage I or II disease. However, the differences between the median survival times for AA and C women presenting with Stage III and IV disease were both highly significant. A significantly lower percentage of AA women became "disease free" after initial therapy as compared with C women (P < 0.001). Interestingly, when data were stratified by stage, only in Stage III and IV were there significant differences between the races for becoming disease free. Conclusions. AA women tend to present at a later stage and have poorer survival from later-stage disease as compared with C women. The poorer survival appears to be related to the decreased ability to achieve disease-free status in AA women with advanced disease. The underlying causes of this difference in treatment outcome need further evaluation.