The neutrophil/lymphocyte ratio as a predictor of peritoneal metastasis during staging laparoscopy for advanced gastric cancer: a retrospective cohort analysis

The use of staging laparoscopy (SL) has become widespread in patients with advanced gastric cancer (GC). This study aimed to evaluate the predictive value of the neutrophil/lymphocyte ratio (NLR) for the presence of peritoneal metastasis during staging laparoscopy in patients with advanced GC. This retrospective analysis was performed in 35 patients with advanced GC who underwent SL at Kanazawa Medical University Hospital between January 2009 and December 2017. Clinicopathological characteristics were examined and multivariate analyses were performed to identify preoperative laboratory parameters that were independently associated with the presence of peritoneal metastasis or cytological malignancy (P/CY positive) during SL. A P/CY-positive result was confirmed during SL in 16 patients (45.7%). Patients with type 4 or diffuse type 3 tumors showed a significantly higher P/CY-positive rate than those with other tumor types (58.3% vs. 18.2%, P = 0.02). In the univariate analysis for preoperative laboratory parameters, NLR (P   3.5) was associated with a significantly higher P/CY-positive rate than a low NLR (≤ 3.5) (83.3% vs. 33.3%, P = 0.01). Moreover, in patients without type 4 or diffuse type 3 tumors, the P/CY-positive rates were 100% and 0% in patients with NLR > 3.5 and NLR ≤ 3.5, respectively. The preoperative NLR was a significant independent predictor of the presence of peritoneal metastasis during SL. Regardless of tumor type, patients with a high NLR could be reasonable candidates for SL. On the other hand, non-diffuse type tumor accompanied by a low NLR may not need to undergo SL.