Prognostic Significance of Number of Lymph Nodes Harvested in Patients with Node Negative Antral Gastric Adenocarcinoma Undergoing Laparoscopic Curative Resection

Abstract

Introduction: The most important parameters affecting patient prognosis in gastric cancer are the T stage and regional lymph node invasion. Although it is known that lymph node positive patients have poor long-term survival and recurrence and metastasis rates are higher than patients with lymph node negative, recurrence and metastasis may also develop in lymph node negative patients. Studies have found that the most likely causes of this situation are mictometastases which cannot be detected in routine pathological examination and the inability to remove a sufficient number of lymph nodes. There is no clear consensus regarding the number of lymph nodes to be removed and there are very few studies in the literature on this subject. Aim: To determine the effect of the number of lymph nodes harvested in laparoscopically resected, lymph node negative, early stage antral gastric adenocarcinoma on patient prognosis. Materials and Methods: A retrospective study was conducted from January 2015 to January 2020 in which 62 patients with pT1N0, pT2N0 and pT3N0 tumour located in gastric antrum were included. Distal gastrectomy, partial omentectomy and lymph node dissection were performed to all patients. The number of lymph nodes harvested were determined from pathology reports. The patients were divided into two groups according to the number of lymph nodes as below 15 or above 15 and clinicopathological variables and overall and disease-free survival rates were compared between these two groups. X2 or Fisher-Exact test and Student-T or Mann-Whitney U test were used for comparing clinicopathological variables and Kaplan-Meier survival curves and Cox regression model for survival analysis. All p-values less than 0.05 were considered statistically significant. Results: It has been found that the mean overall survival in groups with lymph node removal ≥ and <15 was 55.07±2.28 (95% CI: 50.60 ~ 59.55) months and 34.80±4.26 (95% CI: 26.43 ~ 43.17) months and mean disease-free survival was 59.43±1.10 (95% CI: 57.26 ~ 61.59) months and 27.85±4.19 (95% CI: 19.63 ~ 36.07) months, respectively. The difference was statistically significant (p=0.001, p=0.002). Conclusion: Present study concludes that removal of a minimum of 15 lymph nodes in radical gastrectomy and lymphadenectomy is effective on overall and disease-free survival, regardless of the T stage. In addition, removal of 15 or more lymph nodes can provide more accurate and appropriate staging and affect patients’ decision to be directed towards adjuvant therapy.