Onodera's Prognostic Nutritional Index is a novel and useful prognostic marker for gastrointestinal stromal tumors.

Background: Immunoinflammatory markers such as the peripheral blood neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) have gained considerable attention as prognostic markers in gastrointestinal stromal tumors (GISTs).

Aim: To assess the prognostic value of Onodera's Prognostic Nutritional Index (OPNI) for GISTs.

Methods: All patients who had undergone surgical resection for a primary, localized GIST from 2009 to 2016 at our cancer center were initially and retrospectively identified. Recurrence-free survival (RFS) was calculated by the Kaplan-Meier method and compared by the log-rank test. We used multivariate Cox proportional hazard regression models to identify associations with outcome variables.

Results: A total of 235 GISTs were identified and included for analysis under our inclusion criteria. Univariate and multivariate analyses both identified the OPNI as an independent prognostic marker, and the OPNI was associated with the primary site, tumor size, mitotic index, tumor rupture, necrosis, and modified NIH risk classification. Low OPNI (< 51.30; hazard ratio = 5.852; 95% confidence interval: 1.072-31.964; = 0.0414) was associated with worse RFS. The 2- and 5-year RFS rates of the patients with a low OPNI were 92.83% and 76.22%, respectively, whereas 100% and 98.41% were achieved by the patients with a high OPNI.

Conclusion: The preoperative OPNI is a novel and useful prognostic marker for GISTs.