Adverse clinicopathological features in pN0M0 colon cancer: limited added value of routine preoperative blood-based scores

Pathological node negativity does not exclude adverse local or histopathological features in colon cancer. The ability of routinely available inflammatory-nutritional indices to identify such features specifically within pN0 disease remains uncertain. This retrospective single-center cohort used an institutional colon cancer registry covering 2022–2026. Of 234 surgical records, 105 pN-positive cases and 5 pN0 cases with synchronous metastasis were excluded, leaving 124 patients with pN0M0 disease. The primary endpoint was a composite of lymphovascular invasion, perineural invasion, bowel obstruction, or bowel perforation; pT4 disease and 30-day mortality were excluded from the primary definition and evaluated in sensitivity analyses. Eight preoperative indices were recalculated from raw laboratory values using explicit unit-specific formulas. Associations were assessed by logistic regression adjusted for age, sex, ASA class, pT4, tumor size, and emergency surgery. Empirical ROC curves, DeLong confidence intervals, Youden cutoffs, sensitivity analyses, and exploratory overall survival analyses were performed. Among 124 patients with pN0M0 colon cancer, 71 (57.3%) had at least one composite adverse clinicopathological feature. None of the eight inflammatory–nutritional indices differed significantly between patients with and without the primary endpoint or showed an independent association after multivariable adjustment. PNI had an AUC of 0.535 (95% CI 0.433–0.637) and CALLY an AUC of 0.518 (95% CI 0.412–0.624). The clinical covariate model had an apparent AUC of 0.777, and addition of any individual index changed the AUC by no more than 0.006. In exploratory survival analysis, the composite endpoint was associated with worse overall survival (3-year OS, 68.1% vs. 94.1%; log-rank p = 0.002). Preoperative inflammatory-nutritional indices showed no clinically useful discrimination for composite adverse clinicopathological features in pN0M0 colon cancer and should not be used as stand-alone tools for this purpose. Conventional clinicopathological variables were more informative. The exploratory survival findings require external validation and do not establish treatment-predictive utility.