Prognostic Significance of the Extent of Lymph Node Dissection in Gastric Cancer

Yang, Han Kwang; Kang, Sung Bum; Lee, Kuhn Uk; Choe, Kuk Jin; Kim, Yong Il; Kim, Jin Pok

Abstract

PURPOSE: The purpose of this retrospective study is to evaluate the prognostic significance of lymph node dissection in gastric cancer surgery.
MATERIALS AND METHODS
We analysed the survival curves of 1661 cases of gastric cancer patients who received gastric resection from 1987 to 1991, in whom the number of dissected lymph nodes is more than 9 (to minimize stage migration). We used modified TNM system with numeric classification. RESULT: The average number of resected lymph nodes of the study group was 31.5 and there was no significant difference in the average number of resected lymph nodes during the study period. In stage I, IIa, IIb and IV, there was no significant difference in survival curves according to the number of resected lymph nodes (25, 35 or 45). However, in stage IIIa, the 5-year survival rate (5YSR) was better in the patients (n=171) of more than 25 lymph nodes than in the patiens (n=104) of less than 26 resected lymph nodes (64.1% vs. 59.9%, p=0.031). In stage IIIb, 5YSR was better in the patients (n=206) of more than 35 lymph nodes than in the patients (n=307) of less than 36 lymph nodes (33.2% vs. 18.3%, p=0.029). In multivariate analysis, number of dissected lymph node was an independent prognostic factor.
CONCLUSION
Survival benefit of extended lymph node dissection in the gastric cancer surgery is limited in the stage IIIa and IIIb and the recommended number of dissection is more than 35. This study also suggests a positive correlation between tumor stage and required quantity of lymph node dissection for better survival (>25 for stage IIIa and >35 for stage IIIb).