Squamous cell carcinoma of the anal canal: utilization and outcomes of recommended treatment in the United States.

BACKGROUND: Over the past two decades, recommended treatment for squamous cell carcinoma of the anal canal has shifted from surgery to primary chemoradiation. Resection is now reserved for persistent or recurrent disease. Our objectives were (1) to evaluate treatment trends over the past 20 years, (2) to assess contemporary treatment utilization, and (3) to examine the impact of recommended vs nonguideline treatment on survival.
METHODS: From the National Cancer Data Base (1985-2005), 38,882 patients with anal canal cancer were identified. Regression models were used to assess factors associated with use of nonguideline treatment (vs chemoradiation +/-surgery). Univariate and multivariate methods were used to assess the impact of treatment on survival.
RESULTS: From 1985 to 2005, the use of chemoradiation increased significantly with a concomitant decrease in treatment with surgery alone (P < .0001). However, only 74.9% (5014 of 6696) of patients underwent primary chemoradiation therapy in 2003-2005. Overall, 22.7% (1523 of 6696) of patients received treatment that was not concordant with established guidelines: primary surgery (13.0%) and primary chemotherapy or radiation (9.7%). Patients were significantly less likely to receive guideline treatment if male, older, black or Hispanic, more severe comorbidities, or Stage I (vs Stage II or III). Patients undergoing chemoradiation ( +/- surgery) had higher 5-year survival rates than patients who received nonguideline treatment (64% vs 58%; hazard ratio 0.82, 95% confidence interval [95% CI] 0.77-0.87; P < .0001).
CONCLUSION: Primary chemoradiation therapy has supplanted surgical treatment and is associated with better outcomes; however, nearly a quarter of patients are still receiving treatment that is not concordant with established guidelines.