Variation in the Use of Chemoradiotherapy for Stage II and III Anal Cancer: Analysis of the National Cancer Data Base.

Background: Treatment for anal canal cancer has evolved from radical operations to definitive chemoradiotherapy (CRT), which allows for sphincter preservation in most patients.

Objective: The aim of this study was to examine the use of CRT for patients with stage II and III anal cancer, among different patient demographics, geographic regions, and facility types.

Methods: Utilizing the National Cancer Data Base, we examined patients with stage II and III anal canal squamous cell carcinoma from 2003 to 2010. Via univariate analysis, we examined patterns of treatment by patient demographics, tumor characteristics, geographic region, and facility type (academic vs. community). A multivariable logistic regression model was built to evaluate differences in treatment patterns when adjusting by age, sex, race, comorbidities, and stage.

Results: A total of 12,801 patients were analyzed, of which 11,312 (88 %) received CRT. After adjusting for confounders, CRT was less likely to be administered to males [odds ratio (OR) 0.61, 95 % confidence interval (CI) 0.54-0.69], Black patients (OR 0.70, 95 % CI 0.59-0.83), and those with multiple comorbidities (OR 0.60, 95 % CI 0.51-0.72). CRT was not as widely utilized in the West (OR 0.74, 95 % CI 0.59-0.93), and patients treated in academic-based centers were less likely to receive CRT (OR 0.81, 95 % CI 0.72-0.92). Improved median overall survival was observed when CRT was utilized (p = 0.008).

Conclusion: When controlling for age, sex, race, comorbidities, and stage, discrepancies in the use of CRT for anal cancer treatment exist between demographic subtypes, geographical regions, and facility types.