Preoperative neutrophil-to-platelet ratio as a potential prognostic factor for gastric cancer with positive peritoneal lavage cytology in the absence of other non-curative factors: a multi-institutional dataset analysis

Purpose Peritoneal dissemination is the key to the prognosis of gastric cancer (GC) and can be detected early with peritoneal lavage cytology. No studies have examined preoperative prognostic factors in GC patients who have positive cytology but no other non-curative factors. Methods We conducted a retrospective analysis using a multicenter database of 3575 patients who underwent gastrectomy between 2010 and 2014. Patients with positive peritoneal lavage cytology as a sole non-curative factor were retrieved, and correlations between parameters and the prognosis were compared. Results A total of 66 patients were identified as eligible. In the receiver operating characteristic (ROC) curve analysis, the neutrophil-to-platelet ratio (NPR) had the greatest area under the curve value and was selected. We divided the NPR into two groups based on the optimal cutoff value of the NPR (2.000), as determined by the ROC curve analysis. A high preoperative NPR was the only prognostic factor. The NPR-high group had shorter overall survival than the NPR-low group (hazard ratio 1.85, 95% confidence interval 1.05–3.28, P = 0.032). Conclusion Our analysis indicated that the preoperative NPR serves as a prognostic factor in GC patients with positive peritoneal lavage cytology in the absence of other non-curative factors.