Demographic disparities in delay of definitive chemoradiation for anal squamous cell carcinoma: a nationwide analysis

Prolonged time to treatment initiation (TTI) for patients with curable anal cancer may reduce tumor control. This study investigated demographic disparities in TTI for patients receiving definitive chemoradiation (CRT) for anal squamous cell carcinoma (A-SCC).

Adult patients with A-SCC diagnosed from 2004 to 2014 and treated with definitive CRT were identified in the National Cancer Database (NCDB). TTI was defined as days from diagnosis to start of CRT. A negative binomial regression model estimated predicted TTI (pTTI) values. Cox proportional hazards model evaluated the impact of TTI on overall survival (OS).

Overall, 12,546 patients were included with 9% Non-Hispanic Black patients and 4% Hispanic patients. Multivariable analysis (MVA) showed that pTTI varied significantly by race/ethnicity with Non-Hispanic Black patients having a pTTI of 50 vs. 38 days for Non-Hispanic White patients [relative risk (RR), 1.21; 95% confidence interval (CI), 1.17-1.25]. For Hispanic patients, pTTI was 48 days, significantly longer than that of Non-Hispanic White patients (RR, 1.19; 95% CI, 1.14-1.24). Gender, insurance status, education level, urban category, distance to reporting facility, treatment facility type, intensity-modulated radiation therapy (IMRT)/proton use, T/N classification, and comorbidity status were all also associated with significant variation in TTI. TTI was not independently associated with changes in OS on MVA [hazard ratio (HR), 0.999; 95% CI, 0.997-1.002].

Non-Hispanic Black and Hispanic patients have longer delays in starting definitive CRT for A-SCC. While TTI was not associated with OS, future analyses should explore the impact of TTI on local control, metastases, and patient-reported outcomes.