Effect of the number of negative lymph nodes removed on the survival and recurrence rate after gastrectomy in patients with gastric cancer: a multicenter retrospective cohort study

Background Various factors affect the survival rate of Gastric cancer (GC) patients after gastrectomy. This study aimed to investigate the effect of the number of negative lymph nodes (NLNs) removed on GC patients’ survival and recurrence rate after gastrectomy. Methods In this retrospective, multicenter cohort study, we reviewed the medical profile of 639 patients with a definite diagnosis of GC who underwent gastrectomy from 2010 to 2022 in one of the medical centers affiliated with the Iran University of Medical Sciences. Based on the number of NLNs removed, patients were divided into three groups, including (0–9NLNs), (10–15 NLNs), and (≥ 16 NLNs), including 155, 231, and 253 GC patients, respectively. Demographic characteristics, tumor characteristics, and pathological findings of the patients were extracted by referring to the patient’s files. Results The 5-year survival rate of patients was estimated at 48.2%. The 5-year tumor recurrence rate in patients with the number of NLNs 1–9, NLNs 10–15, and ≥ 16 NLNs were 79.4%, 51.1%, and 30.8%, respectively. (Log-rank = 9.24, P 0.001) The multivariate analysis showed that the 5-year survival rate in patients with fewer NLNs removed ≥ 16 was significantly higher than in the other two groups. In addition, age, BMI, tumor size, tumor stage, metastasis, and tumor differentiation were significantly related to the survival of GC patients after gastrectomy. (p < 0.05) Conclusion Paying attention to the number of NLNs removed during gastrectomy can be a key factor in improving the survival prediction of GC patients.