Adherence to treatment guidelines as a major determinant of survival disparities between black and white patients with ovarian cancer

Objective. To evaluate whether non-adherence to National Comprehensive Cancer Network (NCCN) treatment guidelines and other factors related to treatment access contribute to racial disparities in ovarian cancer survival. Methods. This large cohort study included patients from the National Cancer Database who were diagnosed with ovarian cancer between 2004 and 2014, with follow-up data up to 2017. The multivariable Cox regression was used to assess the effect of study variables on five-year overall survival. The proportion contributions of prognostic factors to the survival disparities were estimated using individual and sequential adjustment of these factors based on the Cox proportional hazards models. Results. Of the 120,712 patients eligible for this study, 110,032 (91.1%) were whites and 10,680 (8.9%) were blacks. Black patients, compared with their white counterparts, had a lower adherence to NCCN guidelines (60.8% vs. 70.4%, respectively, P < 0.001), and a higher five-year mortality after cancer diagnosis (age- and tumor characteristics- adjusted hazard ratio: 1.22, 95% confidence interval: 1.19-125). Non-adherence to NCCN treatment guidelines was the most significant contributor to racial disparity in ovarian cancer survival, followed by access to care and comorbidity, each explaining 36.4%, 22.7%, and 18.2% of the racial differences in five-year overall survival, respectively. These factors combined explain 59.1% of racial survival disparities. Risk factors identified for non-adherence to treatment guidelines among blacks include insurance status, treatment facility type, educational attainment, age, and comorbidity. Conclusions. Adherence status to NCCN treatment guidelines is the most important contributor to the survival disparities between black and white patients with ovarian cancer. Our findings call for measures to promote equitable access to guideline-adherence care to improve the survival of black women with ovarian cancer. (C) 2020 Elsevier Inc. All rights reserved.