Prognostic Immune and Nutritional Index as a Predictor of Survival in Patients Undergoing Curative-Intent Resection for Gastric Cancer

Abstract

Background and Objectives: The prognostic immune and nutritional index (PINI) was reported to be clinically relevant for colorectal cancer prognosis. Herein, the utility of PINI as a prognostic factor for the survival of patients with gastric cancer (GC) was investigated. Materials and Methods: We retrospectively analyzed 492 patients with stage I-III GC, predominantly of Asian descent, who underwent curative-intent gastrectomy. Multivariate Cox regression analysis identified independent predictors of overall survival (OS). Model performance was evaluated using the concordance index (C-index), integrated area under the curve (iAUC), time-dependent AUC, integrated discrimination improvement (IDI), and continuous net reclassification improvement (cNRI). Results: The PINI score-calculated as [albumin (g/dL) × 0.9] - [absolute monocyte count (/μL) × 0.0007]-was found to be independently associated with OS (p < 0.001). Additional independent prognostic factors included age, body mass index, 5-factor modified frailty index, tumor-node-metastasis (TMN) stage, gastrectomy type, and anemia. The full model that included all significant covariates outperformed the baseline TNM model, showing significantly higher C-index and iAUC values (both p < 0.001). Compared with an intermediate model, which excluded PINI, the full model demonstrated a superior C-index and iAUC (both p = 0.004). Although the observed improvements in AUC, IDI, and cNRI at 3 years were not statistically significant, the full model achieved significant gains in all three metrics at 5 years, underscoring the added long-term prognostic value of the PINI. Conclusions: PINI is a significant independent predictor of survival in patients with GC who underwent curative-intent surgery. Its inclusion in prognostic models enhances the long-term predictive accuracy for survival, supporting its potential role in guiding personalized postoperative management. External validation in larger multi-ethnic prospective cohorts is essential to confirm its generalizability and to establish its role in routine clinical practice.

Keywords: gastrectomy; monocytes; serum albumin; stomach neoplasm.

Figure 1

Fractional polynomial model of log relative hazard for the prognostic immune and nutritional index (PINI) for overall survival (OS) in patients with gastric cancer (GC). The shaded area represents the 95% confidence interval.

Figure 2

Concordance indices of the predictive models designed to assess OS outcomes in patients with GC for over a 10-year period.

Figure 3

Nomograms predicting 3-year and 5-year OS based on the full model.

Figure 4

Calibration curves of the designed nomogram for predicting (A) 3- and (B) 5-year OS.

Figure 5

Decision curve analysis comparing prognostic models for predicting overall mortality in patients with GC.

Figure 6

Time-dependent differences in area under the curve (AUC) between PINI and serum albumin or absolute monocyte count (AMC). The horizontal dashed line at 0 marks the reference.

Figure 7

Relationship between serum albumin levels and predicted hazard ratio across different AMC levels.