Differences in treatment and survival among African-American and Caucasian women with early stage operable breast cancer

Abstract

Objective. To examine racial disparities associated with breast cancer treatment and survival in elderly patients with early stage operable breast cancer.

Methods. We studied 23,110 women with node-positive and 31,572 women with node-negative tumor who were aged ≥65 with stages I, II, or IIIA breast cancer in 1991–2002 using the Surveillance, Epidemiology and End Results (SEER)-Medicare linked data. Logistic regression analyses were performed to assess the odds of receiving adjuvant chemotherapy and radiation after breast conserving surgery (BCS) for blacks compared to whites. Cox proportional hazard regression models were used to determine the risk of mortality in blacks compared to whites, stratified by types of treatment.

Results. Black women with node-positive and node-negative tumors were 25% (odds ratio = 0.75, 95% CI = 0.65–0.87) and 17% (0.83, 0.70–0.99) less likely to receive chemotherapy than white women, after adjusting for patient and tumor characteristics. This relation was not attenuated and remained statistically significant even after adjustment for socioeconomic status. In women with node-negative tumor who did not receive chemotherapy, black women were significantly more likely to die than white women (hazard ratio (HR) = 1.14, 95% CI = 1.04–1.24) after adjusting for patient and tumor characteristics, and comorbidity; and (1.11, 1.01–1.22) after additionally adjusting for socioeconomic status.

Conclusions. There were racial disparities between black and white women in receiving adjuvant chemotherapy and radiotherapy following BCS. Higher risk of mortality in black compared to white women was found only in those receiving no chemotherapy. Future studies should explore the root causes of racial disparities beyond treatment factors.

Keywords:

• breast cancer
• racial disparity
• chemotherapy
• radiotherapy
• mastectomy
• mortality
• surgery

Acknowledgements

We acknowledge the efforts of the National Cancer Institute, Center for Medicare and Medicaid Services, Information Management Services, Inc.; and the SEER tumor registries in the creation of this database. The analyses, interpretation, and reporting are the sole responsibilities of the authors. This study was supported in part by a grant from the Agency for Healthcare Research and Quality (R01 – HS016743) and a grant from Susan G. Komen for the Cure (KG090010).