Purpose: We identified the frequency of racial disparities in guideline-concordant cancer care for select common disease sites in the United States and the impact of guideline concordance on mortality disparities.
Methods and materials: Using Surveillance, Epidemiology, and End Results Medicare data, we evaluated patients age >65 years of black or non-Hispanic white race who were diagnosed with stage III breast (n = 3607), stage I (n = 14,605) or III (n = 15,609) non-small cell lung, or stage III prostate (n = 3548) cancer between 2006 and 2011. Chemotherapy, surgery, and radiation therapy (RT) treatments were identified using claims data. Pearson χ2 was used to test the associations between race and guideline concordance on the basis of National Comprehensive Cancer Network curative treatment guidelines. Mortality risks were modeled using Cox proportional hazards.
Results: Black patients were less likely to receive guideline-concordant curative treatment than non-Hispanic white patients for stage III breast cancer postmastectomy RT (53% black, 61% white; P = .0014), stage I non-small cell lung cancer stereotactic radiation or surgery (61% black, 75% white; P < .0001), stage III non-small cell lung cancer chemotherapy in addition to RT or surgery (36% black, 41% white; P = .0001), and stage III prostate cancer RT or prostatectomy (82% black, 95% white; P < .0001). Disparities in guideline concordance impacted racial mortality disparities. Specifically, hazard ratios that demonstrated elevated all-cause mortality risks in black patients were lowered (and more closely approached hazard ratio of 1.00) after adjusting for guideline concordance. A similar impact for cause-specific mortality was observed.
Conclusions: Racial disparities in the receipt of curative cancer therapy impacted racial mortality disparities across multiple cancer sites. Benchmarking adherence to guideline-concordant care could represent an opportunity to stimulate improvements in disparities in cancer treatment and survival.