Survival following colorectal cancer resection in nonagenarians: A Swedish nationwide population-based study

Background and aims: To evaluate survival according to treatment strategy among nonagenarians diagnosed with colorectal cancer in Sweden. Methods: This retrospective population-based register study used data from the Swedish Colorectal Cancer Registry. All patients aged ⩾90 years diagnosed with colorectal cancer in Sweden between 2010 and 2019 were included. Patient demographics, tumour characteristics, treatment data, and perioperative outcomes were analysed. Overall survival and relative survival were assessed. Results: A total of 2055 nonagenarians with colorectal cancer were identified. The median age was 91 (range: 90–106), and 1254 (61%) were women. Overall, 1026 patients (50%) underwent bowel resection, of whom 655 (64%) had elective surgery. Among patients undergoing bowel resection, 1- and 3-year overall survival rates were 71% and 37%, respectively. Relative survival was comparable to that of the general population matched for age, sex, and calendar year. Patients who underwent elective resection had significantly longer median survival than those undergoing emergency surgery (37 vs 22 months, p < 0.001). Emergency resection was associated with higher 30- and 90-day mortality than elective resection (15% vs 4%; p < 0.001 and 26% vs 5%; p < 0.001, respectively). In multivariable Cox regression analysis restricted to patients undergoing bowel resection, male sex (hazard ratio = 1.30; standard error = 0.08; p < 0.001), emergency surgery (hazard ratio = 1.70; standard error = 0.09; p < 0.001), advanced tumour stage (hazard ratio = 1.61; standard error = 0.05; p < 0.001), and higher American Society of Anaesthesiologists score (hazard ratio = 1.35; standard error = 0.06; p < 0.001) were independently associated with an increased risk of death. Conclusion: Half of all nonagenarians diagnosed with colorectal cancer underwent bowel resection. Survival following resection was comparable to that expected in the age-matched general population, whereas emergency surgery was associated with substantially higher short-term mortality and poorer long-term survival.