Background:Frailty is characterized by reduced physiologic reserve, and for patients with colon cancer, frailty is associated with increased morbidity after resection. One commonly cited reason for performing an end colostomy vs a primary anastomosis in left-sided colon cancer is the belief that frail patients do not have the physiologic reserve to withstand the morbidity associated with an anastomotic leak. We explored the impact of frailty on the type of operation performed in patients with left-sided colon cancer.Methods:We queried the American College of Surgeons National Surgical Quality Improvement Program for patients with colon cancer who underwent a left-sided colectomy from 2016 to 2018. Patients were categorized using the modified 5-item frailty index. Multivariate regression was used to identify independent predictors of complications and type of operation performed.Results:Of 17,461 patients, 20.7% were considered frail. Frail patients received an end colostomy more often than nonfrail patients (11.3% vs 9.6%,P=0.01). On multivariate analysis, frailty was a significant predictor for total medical complications (odds ratio [OR] 1.45, 95% CI 1.29-1.63) and readmission (OR 1.53, 95% CI 1.32-1.77) but was not independently associated with organ space surgical site infections or reoperation. Frailty was independently associated with receiving an end colostomy vs a primary anastomosis (OR 1.23, 95% CI 1.06-1.44), but an end colostomy did not decrease the risk of reoperation or organ space surgical site infections.Conclusion:Frail patients with left-sided colon cancer are more likely to receive an end colostomy, but an end colostomy does not lower the risk of reoperation or organ space surgical site infections. Based on these results, frailty alone should not prompt the decision to perform an end colostomy, but further studies are needed to guide surgical decision-making in this understudied population.