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

Abstract

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. We examined whether adherence to evidence-based treatment recommendations for endometrial cancer could mitigate survival disparities between black and white women. 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. 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. 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.