Spotting the vulnerable: Preoperative risk stratification in non-metastatic colorectal cancer patients aged 80 years and older.

INTRODUCTION: While colorectal cancer (CRC) surgery is well established in the broader older population, patients aged ≥ 80 years experience a steep rise in frailty, functional dependency, and failure-to-rescue rates. Identifying simple, clinically relevant preoperative indicators may improve risk stratification and guide patient-centered surgical decision-making. METHODS: We retrospectively analyzed 449 patients aged ≥80 years who underwent curative surgery for non-metastatic CRC. Barthel Index (BI) and body mass index (BMI) were evaluated as predictors of one-year mortality. A prognostic nomogram incorporating age, BI, and BMI was constructed. Patients were stratified into low-, medium-, and high-risk groups based on model scores. Performance of the nomogram was assessed with discrimination, calibration, and decision curve analysis. RESULTS: Overall 1-year mortality was 11.6% (n = 52). BI (OR: 0.963, p < 0.001) and BMI (OR: 0.877, p = 0.023) emerged as independent predictors. The nomogram achieved an AUC of 0.746 in the derivation cohort and 0.724 in the validation cohort. High-risk patients exhibited significantly higher major complication rates (17.9% vs. 4.1%, p < 0.001), higher 1-year mortality (22.7% vs. 5.3%, p < 0.001), and inferior overall survival (adjusted HR: 2.112, 95% CI: 1.480-3.013, p < 0.001) compared with low-risk patients. CONCLUSIONS: A nomogram combining age, BI and BMI reliably stratifies postoperative vulnerability and 1-year mortality in patients aged ≥80 years, supporting targeted prehabilitation and surgical shared decision-making.