Effect of the number of lymph nodes harvested on the long-term survival of gastric cancer patients according to tumor stage and location: a 12-year study of 1,637 cases

Background: The effect of the number of lymph nodes harvested on the long-term survival of gastric cancer according to Tumor, Node, and Metastasis (TNM) stage and tumor location remains unclear.

Methods: Patients who underwent gastrectomy for gastric cancer (1998 to 2009) were evaluated retrospectively (1,637 patients). The patients' clinicopathological variables, overall survival (OS), and progression-free survival (PFS) were recorded. The effect of the number of lymph nodes harvested on survival was analyzed according to TNM stage and tumor location.

Results: Harvest of greater than 30 lymph nodes was associated with significantly better OS and PFS than less than or equal to 14 lymph nodes, but no significant difference was observed between less than or equal to 14 and 15 to 29 lymph nodes harvested. The number of lymph nodes harvested was significantly associated with the OS or/and PFS of late stage cancer (N+, T3 to T4, and stage III to IV), harvest of greater than 30 lymph nodes brought significantly better survival compared with the other 2 groups. A higher number of harvested lymph nodes was associated with significantly better PFS for gastric cancer of the body of stomach, but not for proximal, distal, and whole stomach cancer. When the tumor was located in the body of the stomach, the PFS was better with 15 to 29 lymph nodes than less than 14 lymph nodes; however, the OS and PFS were not significantly different between greater than 30 lymph nodes and 15 to 29 lymph nodes. TNM stage and number of lymph nodes harvested were the independent risk factors affecting the survival.

Conclusion: Tailored lymphadenectomy according to TNM stage and tumor location might be considered for gastric cancer patients.