The neutrophil/lymphocyte ratio as a predictor of successful conversion surgery for stage IV gastric cancer: a retrospective study

BACKGROUND: Conversion surgery (CS) following a response to chemotherapy occasionally leads to prolonged survival in patients with stage IV gastric cancer (GC). This study aimed to evaluate the predictive value of the neutrophil/lymphocyte ratio (NLR) for the success of CS in patients with stage IV GC. METHODS: We retrospectively analyzed data of 50 patients with stage IV GC who received systemic chemotherapy between January 2009 and December 2017 at the Kanazawa Medical University Hospital. The successful CS group included the patients who underwent R0 or R1 resection with CS, and the failed CS group included the patients who did not undergo CS after chemotherapy or those who, despite undergoing CS, had to additionally undergo R2 resection. Clinicopathological characteristics were examined in both groups. Univariate and multivariate analyses were performed to identify pretherapeutic parameters that were independently associated with the achievement of successful CS. RESULTS: The number of patients in the successful and failed CS groups were 12 and 38, respectively. On univariate analysis, gender (P = 0.01), NLR (P = 0.003), albumin levels (P = 0.004), and absence of peritoneal metastasis (P = 0.004) were found to be significantly correlated with a successful CS. On multivariate analysis, NLR < 4 and absence of peritoneal metastasis were independently correlated with a successful CS (P = 0.02 and P = 0.002, respectively). In patients without peritoneal metastasis, successful CS rates in patients with NLR < 4 were significantly higher than those in patients with NLR ≥ 4 (61.1% vs. 10.0%, P = 0.005). CONCLUSIONS: The NLR was a significant independent predictor of the achievement of successful CS in stage IV GC patients, especially among the patients without peritoneal metastasis. Patients with a low NLR could have higher possibility of achieving successful CS.