Racial and socioeconomic disparities in adjuvant chemotherapy for older women with lymph node-positive, operable breast cancer

Abstract

Background: Consistent with findings from clinical trials, a recent population-based study indicated that adjuvant chemotherapy for lymph node-positive, operable breast cancer is effective at improving survival in older women, specifically those ages 65 years to 69 years; however, to the authors' knowledge, no conclusion has been reached about the relative benefit of chemotherapy for women aged > or =70 years, probably because of small number of patients. However, little is known about racial and socioeconomic disparities in adjuvant chemotherapy for breast cancer among older women.

Methods: This study included 14,177 white women and 1277 black women aged > or =65 years who were diagnosed with operable breast cancer (stage II-IIIA) and positive lymph nodes between 1991 and 2002. These women were identified from the Surveillance, Epidemiology, and End Results and Medicare-linked database. Multivariate logistic regression was used to compute the odds ratios of receiving chemotherapy among black women compared with white women, and the causal step approach was used to test whether census tract-level poverty mediated racial disparities.

Results: Interaction terms analyses indicated that regressions should be stratified by age group. In the group ages 65 years to 69 years, the adjusted odds ratio of receiving chemotherapy were lower for black women than for white women (odds ratio, 0.85; 95% confidence interval, 0.57-0.97). Poverty mediated the association between chemotherapy and race in this age group. No racial or socioeconomic disparities were observed among women aged > or =70 years.

Conclusions: This study documented racial disparities in adjuvant chemotherapy that were mediated by poverty in women ages 65 years to 69 years, an age group for which there is clear evidence for the efficacy of chemotherapy, but no disparities were observed among women aged > or =70 years. The authors concluded that it is important to work toward reducing treatment disparities among older women.