5-year Overall Survival Analysis
In the unadjusted survival analysis, black HPV-positive OPSCC patients had significantly worse 5-year OS compared to white patients (HR 4.9, 95% CI 2.2-11.1, p<0.0001). We next sequentially adjusted for demographic, clinical, and SES variables. First, after adjustment for age, sex, T stage, N disease, and distant metastases, the racial disparity in 5-year OS remained statistically significant (HR 4.6, 95% CI 1.8-12.0, p=0.002) (Table II) . As expected, T4 disease was associated with significantly worse 5-year overall survival compared to T1 disease (HR 2.5, 95% CI 1.0-6.3). Nodal disease and the presence of distant metastases at diagnosis were associated with elevated but non-statistically significant risk of death.
Second, smoking and alcohol use were added to the previous adjustment set. The association between black race and worse 5-year overall survival persisted (HR 4.1, 95% CI 1.5-11.4, p=0.007) (Table III) . Neither smoking (>10 pack-years) nor alcohol use was significantly associated with worse overall survival (HR 1.0, 95% CI 0.5-2.2 and HR 1.6, 95% CI 0.5-4.6, respectively).
Finally, individual-level education, household income, and insurance status were added to the previous adjustment set, and the racial disparity remained statistically significant (HR 3.4, 95% CI 1.1-10.1, p=0.028) (Table IV) . Having no insurance (HR 3.0, 95% 0.9-9.8) and a household income <$20,000 (HR 1.9, 95% CI 0.5-6.6) were associated with non-significant trends towards worse overall survival in the fully adjusted model.