Real-World Results of Curative Open Colorectal Cancer Surgery in Octogenarians: Long-Term Survival Despite High Frailty Burden

Background: Octogenarians represent a rapidly growing subgroup of patients with colorectal cancer, yet evidence guiding perioperative risk stratification and long-term outcomes after major colorectal surgery remains limited. This study aimed to evaluate perioperative and survival outcomes in octogenarians undergoing curative open colorectal surgery. Methods: This single-center observational cohort study included consecutive patients aged ≥80 years who underwent curative open colorectal cancer surgery between 2013 and 2024. Frailty was assessed using the 5-item modified frailty index (mFI-5). Postoperative morbidity, 30-day mortality, and long-term overall survival were analyzed. Outcomes were compared between colon and rectal resections. Exploratory discrimination analyses assessed the ability of age, frailty, and major comorbidities to identify postoperative morbidity. Survival was assessed using Kaplan–Meier analysis. Results: A total of 112 patients were included (mean age 83.1 ± 2.8 years; 54.5% male), of whom 90.2% were classified as frail (mFI-5 ≥ 1). Overall postoperative morbidity occurred in 41.9% of patients and 30-day mortality was 4.5%. No significant differences in morbidity or mortality were observed between colon and rectal resections. ROC analyses demonstrated limited discriminatory ability for postoperative morbidity across all evaluated variables, with age showing the highest AUC at 0.590. Estimated OS at 1, 3, and 5 years was 81.8%, 72.7%, and 58.2% in non-frail patients and 86.1%, 64.7%, and 47.0% in frail patients, respectively (log-rank p = 0.841). Conclusions: Major open colorectal surgery in octogenarians is associated with acceptable perioperative morbidity and mortality and favorable long-term survival despite high frailty burden.