Impact of quality of care on racial disparities in survival for endometrial cancer

BACKGROUND: Black women experience poorer survival compared with white women across all endometrial cancer stages and histologies. The incidence of endometrial cancer is 30% lower in black women compared with white women, yet mortality is 80% higher in black women. Differences in adherence to evidence-based guidelines have been proposed to be major contributors to this disparity. OBJECTIVES: We examined whether adherence to evidence-based treatment recommendations for endometrial cancer could mitigate survival disparities between black and white women. STUDY DESIGN: The National Cancer Database was used to identify women with endometrial cancer treated from 2004 through 2016. We established 5 evidence-based quality metrics based on review of primary literature and accepted guidelines: surgical treatment within 6 weeks of diagnosis (Q1), use of minimally invasive surgery (stage I-IIIC; Q2), pelvic nodal assessment (high-risk tumors; Q3), adjuvant radiation (high intermediate risk; Q4), and systemic chemotherapy (stage III-IV; Q5). The rates of 30 and 90 day mortality and 5 year survival were compared between black and white women. To determine the influence of quality on outcomes, we compared outcomes among perfectly adherent black and white women with stage I and III endometrial cancer. RESULTS: We identified 310,208 women including 35,035 (11.3%) black women and 275,173 (88.3%) white women. Black women were less likely than white women to receive Q1 (65.8 vs 75.6%), Q2 (58.5 vs 72.9%), Q3 (71.3 vs 74.2%), and Q5 (72.7 vs 73.2%) (P < .05 for all). Adherence to each quality metrics was associated with improved survival. Among women with stage I disease, perfect adherence to the relative quality metrics was seen in 53.1% of white and 41.5% of black women. Among perfectly adherent stage I patients, outcomes in black women improved relative to unselected black women; however, they still experienced higher risk of 30 day (adjusted relative risk, 2.25; 95% confidence interval, 1.30-3.90), 90 day (adjusted relative risk, 1.84; 95% confidence interval, 1.23-2.76), and 5 year mortality (adjusted hazard ratio, 1.42; 95% confidence interval, 1.26-1.59) compared with similar white women. Among women with stage III tumors, perfect adherence to the relative quality metrics was seen in 56.6% of white and 44.1% of black women. Perfectly adherent black women with stage III disease had improved outcomes but remained at increased risk of 30 day (adjusted relative risk, 1.86; 95% confidence interval, 1.01-3.44) and 5 year mortality (adjusted hazard ratio, 1.35; 95% confidence interval, 1.22-1.50) compared with white women. CONCLUSION: Black women are less likely than white women with endometrial cancer to receive evidence-based care. However, receipt of evidence-based care mitigates but does not eliminate racial disparities in outcomes and black women remain at greater risk of death from endometrial cancer.