Objective: To explore the relationship between the lymph node count and prognosis in stage II gastric cancer.
Methods: Retrospective analysis was performed for the 268 cases with gastric cancer who underwent parallel D(2) dissection between January 1990 and December 2006 in the Sun Yat-Sen Cancer Center. The Japanese Gastric Cancer Association(JGCA) 13th edition of pathological staging system was used to define stage II gastric cancer. Patients were followed up until December 2008. The Kaplan-Meier method and chi-square test were used for data analysis. All the data were analyzed using SPSS16.0 for Windows.
Results: The average number of detected lymph nodes was 17.3+/-1.2. There were 109 patients with detected lymph node <15. The 1-, 3-, and 5-year survival rates were 92.7%, 67.8%, and 50.9%, respectively. The number of detected lymph node was > or =15 in 159 cases, and the 1-, 3-, and 5-year survival rates were 96.9 %, 81.0%, and 66.4%, respectively. The difference between two groups was statistically significant (P=0.003). Further analysis of the 199 cases with no lymph node metastasis (pN(0) group) showed that there were 95 cases with lymph nodes <15, and the 1-, 3-, and 5-year survival rates were 92.6%, 70.4%, and 55.9%, respectively. There were 104 patients with > or =15 lymph nodes, and the 1-, 3-, and 5-year survival rates were 97.1%, 84.4%, and 66.8%, respectively. The difference was also statistically significant (P=0.049). There were 69 cases with lymph node metastasis (PN(1) group), and the 1-, 3-, and 5-year survival rates of 14 patients with lymph nodes <15 were 92.9%,57.1%, and 34.3%, respectively. Comparing two groups, the survival rate was significantly different (P=0.034). There were 55 patients with > or =15 lymph nodes, and the 1-, 3-, and 5-year survival rates were 96.4%, 73.4%, and 63.8%. The difference was statistically significant (P=0.036).
Conclusion: In patients with stage II gastric cancer as defined by the JGCA 13th edition, the survival rate is better in patients with more than 15 detected lymph nodes as compared to those with less than 15.