Preoperative Immunonutritional Indices in Colorectal Cancer: The Contribution of Albumin, Time-Dependence of Effect, and Threshold Transportability in a Saudi Cohort

Vollständiger Abstract

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Preoperative immunonutritional indices are widely reported to predict survival after colorectal cancer (CRC) resection, yet their independence varies across cohorts and no data exist from the Arab Gulf. In this retrospective cohort study we analyzed 316 patients undergoing curative resection for stage I–III colorectal adenocarcinoma at a Saudi tertiary center between 2013 and 2022, of whom 48 (15.2%) presented as emergencies. The prognostic nutritional index (PNI) and a composite albumin–neutrophil-to-lymphocyte ratio (albumin–NLR) score were assessed against overall survival (OS) and disease-free survival (DFS) using Cox models adjusted for age, sex, emergency presentation, tumor site, neoadjuvant therapy, adjuvant chemotherapy and lymphovascular invasion and stratified by stage and American Society of Anesthesiologists class. Over a median follow-up of 58.1 months there were 88 deaths and 124 DFS events. The PNI independently predicted OS (adjusted hazard ratio 0.958, 95% CI 0.929–0.987) and DFS (0.964, 0.940–0.988); the albumin–NLR score did not. Albumin alone carried the signal (OS 0.938), with lymphocytes, neutrophils and the NLR all null. The PNI effect was confined to the first 36 months (0.944 versus 1.003 thereafter), and published cut-offs classified 70.8% of the cohort as high-risk. Immunonutritional prognostication in CRC is albumin-driven, time-limited and sensitive to cut-off provenance.