Impact of the number of lymph nodes harvested in gastric cancer patients prognosis

Introduction: The number of lymph nodes harvested could be an important prognostic factor in gastric cancer. Currently, the established cut-off for adequate staging is 15 lymph nodes, however this seems not always appropriate if we want to improve survival. The aim of our study is to evaluate the effect of the number of lymph nodes harvested on gastric cancer patients prognosis. Methods: A retrospective analysis of a prospective database with 476 gastric cancer cases submitted to curative intent surgery, between January 2010 and December 2015, in an Upper GI Surgery Unit. We analyzed 288 patients that met the inclusion criteria for this study (cases of non-resectional or palliative surgery were excluded). Overall survival (OS), disease specific survival (DSS) and disease free survival (DFS) curves according to the number of LN retrieved were calculated and adjusted to pathological stage, type of tumor (EGC vs advanced) and pN. Results: Most patients (86,1%) had more than 15 lymph nodes retrieved. Harvesting more than 15 lymph nodes had positive effects on the OS of patients with pStage I tumors, early gastric cancer and pN negative tumors. Retrieving more than 15 lymph nodes contributed to improvements in DSS and DFS of patients with pStage II tumors. When more than 30 lymph nodes were retrieved the OS of gastric cancer patients was significantly better not only in pStage I tumors, early gastric cancer and pN- tumors, but also in pStage III tumors. Harvesting more than 30 lymph nodes was also associated with better DSS and DFS in pStage II gastric cancer patients. The number of LN retrieved did not associate with more morbidity, but slightly increased the surgery duration. Conclusion: The number of lymph nodes harvested appears to have prognostic impact on gastric cancer patients survival and lymphadenectomy extension should be individually designed for each patient according to tumor stage.