In older patients with stage I anal cancer, radiation alone may be associated with adequate oncologic outcomes when compared to chemoradiation. The population-based study included Medicare eligible patients with stage I squamous cell carcinoma of the anus and treated with either definitive radiation alone or chemoradiation. Outcomes included overall survival, disease-free survival, cause-specific survival, colostomy-free survival, and acute or late toxicities. Among the findings:

• 200 patients (median age 72 years) with squamous cell carcinoma of the anus were identified who received chemoradiation vs 99 treated with lone radiotherapy.
• Patients receiving chemoradiation improved unadjusted overall survival compared with line radiotherapy, but after adjustment, there was no difference in overall survival, cause-specific survival, colostomy-free survival, or disease-free survival.
• Chemoradiation was associated with an increased risk of select early and late toxicities.