Colorectal cancer surgery in elderly patients 80 years and older: a comparison with younger age groups.

Background: A reduction in complications and mortality can be observed over the last few decades among elderly patients in the early postoperative period for colorectal cancer (CRC) surgery, but long-term outcomes are largely unknown. This study aimed to investigate the long-term outcomes of elderly patients 80 years and older after CRC surgery in comparison with younger age groups. The influence of clinical, oncological, and physical parameters on outcome were retrospectively analyzed. Methods: A total of 346 patients underwent CRC surgery with curative intent between January 2013 and December 2017. Patients were divided into three age groups: younger than 60 (n=47), between 60 and 79 (n=218), and 80 and older (n=81). Clinicopathological variables including comorbidity, modified frailty index, prognostic nutrition index (PNI), operative/postoperative data, and outcome including cause of death were compared among age groups. To identify factors associated with death from CRC and other causes, univariate and multivariate analyses using the Cox proportional hazards model were performed. Results: Immediate postoperative morbidity of patients with Clavien-Dindo grades of III or greater (16.0%) and the 30-day mortality rate (2.5%) of patients 80 years and older were not statistically different from those of younger age groups. Long-term disease-free survival was also similar among age groups, suggesting CRC surgery provides oncological benefit to patients irrespective of age. Multivariate analysis revealed that R1 resection, advanced tumor stage, carcinoembryonic antigen (CEA) level of >5 ng/mL, undifferentiated tumor, and longer postoperative hospital stay were risk factors for CRC death. Long-term overall survival was significantly reduced in comparison to younger age groups. Seventy percent of deaths in elderly patients during follow-up were primarily from respiratory failure and cardiovascular disease. Multivariate analysis demonstrated that advanced age, frailty, low PNI, and open procedure were risk factors for other causes of mortality. Conclusions: Elderly patients undergoing CRC surgery appeared to enjoy similar oncological benefits as younger age groups. Since both modified frailty index and PNI were correlated with mortality unrelated to CRC, preoperative assessment of these factors can be important for predicting outcome and selecting patients for prehabilitation.