Influence of age and comorbidity on prognosis and application of adjuvant chemotherapy in elderly Japanese patients with colorectal cancer: A retrospective multicentre study

Abstract Background Adjuvant therapy for colorectal cancer (CRC) in patients aged ≥75 years is supported by inadequate evidence, although such patients are increasing in number worldwide. Patients and methods We assessed the influence of age and comorbidities on the prognosis of CRC in elderly patients using pooled data by the Japanese Study Group for Postoperative Follow-up of Colorectal Cancer. In total, 4598 patients (3304 with colon cancer and 1294 with rectal cancer) who underwent curative surgery from 2004 to 2006 were analysed with respect to age, Charlson comorbidity score (CS), tumour marker positivity, adjuvant therapy and prognosis. Results The number of patients aged 75 years was 2007 (44%), 1614 (35%) and 977 (21%), respectively. Tumour location, tumour marker positivity, clinical stage, performance of adjuvant therapy, CS and overall survival (OS) were significantly different among these age groups ( P