Frailty as a determinant of surgical morbidity, adjuvant therapy feasibility, and survival in octogenarian patients undergoing gastrointestinal cancer resection

Frailty has emerged as a critical determinant of postoperative morbidity, mortality, and survival in elderly cancer patients. However, evidence focusing specifically on octogenarian patients undergoing major gastrointestinal cancer surgery remains limited. This retrospective cohort study included 274 patients aged ≥ 80 years who underwent curative-intent colorectal or gastric cancer surgery at Erzurum City Hospital between 2015 and 2025. Patients were stratified into Low (0–1), Medium (2), and High (≥ 3) frailty groups using the modified Frailty Index-5 (mFI-5). Perioperative outcomes, adjuvant therapy feasibility, overall survival (OS), and recurrence-free survival (RFS) were evaluated and compared across frailty categories. Of the 274 patients, 153 (55.8%) were classified as low frailty, 81 (29.6%) as medium frailty, and 40 (14.6%) as high frailty. Increasing frailty severity was associated with higher rates of major postoperative complications (12.5%, 27.8%, and 46.9%) and higher observed 90-day mortality (13.7%, 14.8%, and 37.5%). Median length of hospital stay differed across frailty groups and was 9.0 (IQR 6.0–12.0) days in Low frailty, 8.0 (IQR 6.0–12.0) days in Medium frailty, and 12.0 (IQR 8.0–15.0) days in High frailty patients. In multivariable analyses, high frailty was independently associated with higher 90-day major morbidity (adjusted OR 8.92, 95% CI 2.09–38.12; p = 0.003) and poorer OS (adjusted HR 3.70, 95% CI 1.88–7.28; p < 0.001). High frailty was also associated with poorer RFS in adjusted analyses (adjusted HR 3.85, 95% CI 1.41–10.50; p = 0.008). Preoperative frailty, as assessed by the mFI-5, is associated with increased perioperative morbidity and worse survival outcomes in octogenarian patients undergoing colorectal or gastric cancer surgery. Routine frailty assessment may support risk stratification and shared decision-making in this vulnerable population.