Age and adjuvant chemotherapy use after surgery for stage III colon cancer

Background: Randomized trials have established that 5-fluorouracil-based ad juvant chemotherapy following resection of stage III colon cancer reduces s ubsequent mortality by as much as 30%, However, the extent to which adjuvan t therapy is used outside the clinical trial setting, particularly among th e elderly, is unknown. Methods: A retrospective cohort study utilizing the Surveillance, Epidemiology, and End Results/Medicare-linked database identi fied 6262 patients aged 65 years and older with resected stage III colon ca ncer. The primary outcome was chemotherapy use within 3 months of surgery, as ascertained from Medicare claims. We examined the extent to which age at diagnosis was associated with adjuvant chemotherapy usage, and we adjusted for potential confounding based on differences in other patient characteri stics with the use of multiple logistic regression. All P values were two-s ided. Results: Age at diagnosis was the strongest determinant of chemothera py: 78% of patients aged 65-69 years, 74% of those aged 70-74 years, 58% of those aged 75-79 years, 34% of those aged 80-84 years, and 11% of those ag ed 85-89 years received postoperative chemotherapy. The age trend remained pronounced after adjustment for potential confounding based on variation in patients' demographic and clinical characteristics and after exclusion of patients with any evident comorbidity tall P values < .001). Conclusions: A djuvant chemotherapy for stage III colon cancer is used extensively, especi ally for patients under the age of 75 years, However, treatment rates decli ne dramatically with chronologic age. Because patients in their 70s and eve n 80s have a reasonable life expectancy, further efforts are needed to ensu re that elderly patients have the opportunity to make informed decisions re garding this potentially curative treatment.