Adjuvant chemotherapy for stage III colon cancer in the oldest old

Abstract

BACKGROUND: Randomized trials demonstrating the benefits of chemotherapy in patients with American Joint Committee on Cancer stage III colon cancer underrepresent persons aged = 75 years. The generalizability of these studies to a growing elderly population remains unknown. METHODS: Using the California Cancer Registry for 1994 through 2008, the authors conducted a population-based study of postcolectomy patients aged 50 years to 94 years with stage III (N1M0) colon adenocarcinoma. A 2-sided chi-square test and Cochran-Armitage test for trend were used to compare patient and tumor characteristics associated with receipt of chemotherapy across age groups. Multivariate regression was used to assess the association between older age and receipt of chemotherapy. Kaplan-Meier methods and Cox proportional hazards modeling were used to evaluate the association between chemotherapy and mortality, with propensity score adjustment. RESULTS: Approximately 44\% (12,382 patients) of the study cohort was aged = 75 years. Persons aged = 75 years were found to be less likely to have received adjuvant chemotherapy than those aged < 75 years (30\% vs 68\% in patients aged 50 years-74 years; P