Reduced risk of distant recurrence after adjuvant chemotherapy in patients with stage III colon cancer aged 75 years or older

Little is known about the effects of adjuvant chemotherapy on the risk of distant recurrence in elderly with stage III colon cancer, treated in daily practice. One thousand two hundred and ninety-one stage III colon cancer patients diagnosed in the southern Netherlands between 2003 and 2008 were included. Propensity score matching was applied to create a subsample to reduce bias caused by differences between patients receiving adjuvant chemotherapy and patients not receiving adjuvant chemotherapy. For both the total study population and the propensity score matched sample, Cox regression analysis was used to discriminate independent risk factors for distant recurrence. Adjuvant chemotherapy (CT) was correlated with a reduced risk of distant recurrence in both the total study population [hazard ratio (HR) CT versus nCT 0.55, 95% confidence interval (CI) 0.42-0.70] and in the propensity score matched sample (HR CT versus nCT 0.46, 95% CI 0.33-0.63). In separate analyses for patients aged < 75 and >= 75 years, the effect of adjuvant chemotherapy on the risk of distant recurrence remained comparable for both age groups (HR CT versus nCT 0.50, 95% CI 0.37-0.68 and 0.57, 95% CI 0.36-0.90, respectively). Distant recurrence risks at higher age definitely warrant consideration of adjuvant chemotherapy for elderly stage III colon cancer patients. This decision should be based on a multidisciplinary and functional assessment of the patient, not on age.