Who Gets Adjuvant Treatment for Stage II and III Rectal Cancer? Insight From Surveillance, Epidemiology, and End Results–Medicare

To examine the relationship between patient characteristics and the use of adjuvant pelvic radiation with and without chemotherapy among patients aged 65 years and older with stage II and III rectal cancer. A retrospective cohort study using the Surveillance, Epidemiology, and End Results-Medicare linked database identified 1,411 patients aged 65 and older with resected stage II and III rectal cancers diagnosed between 1992 and 1996. From claims submitted to Medicare, we measured the use of pelvic radiation therapy with or without chemotherapy and pre- or postoperatively. Fifty-seven percent of patients received radiation, 42% received chemotherapy and radiation, and 7% had treatment delivered preoperatively. Age was the strongest determinant of treatment: 73% of patients aged 65 to 69, 66% aged 70 to 75, 52% aged 75 to 79, 39% aged 80 to 84, and 21% aged 85 to 89 received radiation. The age trend remained strong after adjusting for other factors that predict receipt of treatment and after exclusion of patients with any evident comorbidity (P