Integrated prognostic model of perineural invasion and lymph node ratio for survival prediction in stage III rectal cancer.

Cheng, Xiaofei; Li, Yanqing; Zhao, Feng; Ke, Bingxin; Liu, Fanlong · Surgery · 2026

retrospective_cohort · Level III

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Abstract

Stage III rectal cancer prognosis remains challenging despite therapeutic advances. This study investigates the combined prognostic value of perineural invasion and lymph node ratio, 2 established markers that have not been studied synergistically. Retrospective analysis of 3,881 patients from the Surveillance, Epidemiology, and End Results database (training cohort) and 498 patients from 2 Chinese hospitals (validation cohort). Cox regression identified prognostic factors, and a subsequent nomogram was developed for 3-/5-year cancer-specific survival. Perineural invasion-positive patients showed significantly lower 3-year (74.7% vs 86.7%) and 5-year cancer-specific survival (61.7% vs 76.0%) than perineural invasion-negative counterparts (P < .0001). Lymph node ratio stratification revealed that perineural invasion had a stronger prognostic impact in the lymph node ratio ≤0.5 subgroups. The integrated nomogram incorporating perineural invasion, lymph node ratio, tumor grade, carcinoembryonic antigen status, and treatment parameters demonstrated high accuracy (area under the curve, 0.764-0.839) with excellent calibration. Perineural invasion and lymph node ratio synergistically predict survival in stage III rectal cancer. The validated nomogram provides a practical tool for individualized prognosis assessment and therapeutic decision-making, addressing current gaps in risk stratification.