Race- and sex-based disparities in the therapy and outcomes of squamous cell carcinoma of the anus

Background: Squamous cell carcinoma of the anus (SCCA) is one of the few cancers with an increasing incidence in the United States. We aimed to characterize race- and sex-based disparities in receipt of therapy and overall survival (OS) of SCCA using the SEER database. Methods: Cases of locoregional SCCA (T2-T4 any N M0) diagnosed between 2000 and 2012 in the SEER database were included. Demographics, tumor characteristics, type of therapy, and outcomes were extracted. Univariable and multivariable Cox proportional hazard models were constructed to test factors associated with OS. Data were reported as hazard ratios (HRs) and 95% CIs. Results: A total of 7,882 cases of locoregional SCCA were identified, with a median age of 58 years, 61.2% of whom were women, and 86.3% were white. Most patients (82.3%) received radiation therapy (RT), with the lowest rate in black men (76.7%) and the highest in white women (86.1%). The median OS was 135 months; OS was lower in elderly patients (age ≥65 years; 68 months), men (108 months), blacks (109 months), and those who did not receive RT (121 months). In multivariable analysis, age (HR, 1.19; 95% CI, 1.17-1.21 per 5 years increase), sex (HR, 1.59; 95% CI, 1.47-1.73, men vs women), race (HR, 1.51; 95% CI, 1.34-1.71, black vs white), and RT (HR, 0.90; 95% CI, 0.82-0.99) were independently associated with OS (P<.05). Conclusions: Significant race- and sex-based disparities exist in survival of patients with locoregional SCCA. Further investigation into the causes of these disparities and methods for elimination are warranted.