Objective:

To evaluate the prognostic relevance of preoperative NPAR in colorectal cancer patients undergoing radical surgery and to develop NPAR-integrated prognostic models for overall survival (OS) and disease-free survival (DFS).

Approach:

• Study Design: Retrospective study including 581 patients with CRC as the training cohort and 483 patients for external validation.
• Data Analysis: Cox regression, nomogram development, time-dependent ROC analysis, calibration, and decision-curve analysis were performed.

Key Findings:

• Higher preoperative NPAR was associated with adverse clinicopathological features.
• Each 1-SD increase in NPAR was linked to shorter OS (HR 2.19, 95% CI 1.90–2.53, p < 0.001) and DFS (HR 1.88, 95% CI 1.62–2.19, p < 0.001) in the training cohort.
• In the external cohort, the association was consistent but attenuated for OS (HR 1.21, 95% CI 1.08–1.35, p < 0.001) and DFS (HR 1.24, 95% CI 1.12–1.37, p < 0.001).
• Adding NPAR to the baseline model did not significantly improve predictive value for OS and showed limited value for DFS.

Interpretation:

Preoperative NPAR is associated with OS and DFS, but its incremental predictive value beyond conventional factors is limited.

Limitations:

• The study is retrospective and may have biases inherent to this design.
• External validation showed lower C-indexes, indicating potential overfitting in the training cohort.

Conclusion:

NPAR may serve as a simple adjunctive marker of inflammatory and nutritional status.