Stratified Survival Analysis After Adjuvant Chemotherapy of Colon Cancer Reveals a Benefit for Older Patients

Adjuvant treatment is still controversially discussed for elderly colon cancer (CC) patients. Our aim was to investigate the benefit of adjuvant treatment for younger (<70 years) and elderly (≥70 years) patients.The long-term outcome of patients (n=855) enrolled in a randomized controlled trial comparing adjuvant chemotherapy with 5-FU alone, 5-FU plus folinic acid (FA), and 5-FU plus interferon-alpha (IFNa) was compared in younger (<70 years) and elderly (≥70 years) patients using a quotient of each patient's survival time and his expected residual life expectancy (QSL) and a multivariate Cox proportional hazards model.Eight-year overall survival (OS) rates were 58.3% and 57.4% for younger (n=653) and elderly (n=202) patients, respectively. In elderly patients, 8-year OS rates were 51.4%, 61.8%, and 56.3, and median QSL scores were 0.338, 0.371, and 0.343 for 5-FU (n=59), 5-FU plus FA (n=76), and 5-FU plus IFNa (n=67), respectively. In elderly patients treatment with 5-FU plus FA decreased the risk for an event by 1.5-fold compared to 5-FU (HR=0.657, 95%CI=0.495-0.870, p=0.004) and 5-FU plus INFa (HR=0.685, 95%CI=0.515-0.912, p=0.009).Our analysis clearly demonstrates for the first time an additional benefit of FA for adjuvant treatment of elderly CC patients. We conclude that this regimen is very safe and effective for adjuvant treatment of elderly patients.