Abstract: Objective:To investigate the prognostic factors of low and undifferentiated gastric cancer with negative metastasis of lymph nodes.
Methods:The clinicopathological data of 270 patients with low and undifferentiated gastric cancer and negative metastasis of lymph nodes who were admitted to the Tianjin Cancer Hospital from January 2002 to December 2007 were retrospectively analyzed. All the patients received radical gastrectomy. One hundred and sixtyone patients had the number of lymph nodes dissected under 15, 53 patients had 15-20 lymph nodes dissected, 33 had 21-30 lymph nodes dissected and 23 patients with the number of 〖HJ*6〗lymph nodes dissected more than 30. Patients were followed up via outpatient examination, phone call and mail till October 2013. The prognosis analysis was done by COX stepwise regression. The survival curve was drawn by KaplanMeier method, and the survival was analyzed using the Logrank test.
Results:All the patients were followed up for a median time of 63 months (range, 2103 months). The median survival time was 63 months (range, 2103 months), and the 1, 3, 5year overall survival rates were 93.0%, 69.5% and 58.5%, respectively. The median survival time of the 161 patients with the number of lymph nodes dissected under 15 was 58 months (range, 2-103 months) , and the 1, 3, 5 year survival rates were 91.4%, 59.3% and 48.8%, respectively. The median survival time of the 53 patients with the number of lymph nodes dissected between 15 and 20 was 68 months (range, 4-95 months), and the 1, 3, 5year survival rates were 94.3%, 84.9% and 71.7%, respectively. The median survival time of the 33 patients with the number of lymph nodes dissected between 21 and 30 was 68 months (range, 34-94 months), and the 1, 3, 5year survival rates were 100.0%, 97.0% and 87.9%, respectively. The median survival time of the 23 patients with the number of lymph nodes dissected more than 30 was 60 months (range, 2-84 months), and the 1, 3, 5year survival rates were 87.5%, 62.5% and 54.2%, respectively. There was significant difference in the prognosis between the 4 groups (χ ²=25.077, P<0.05). There was significant difference in the prognosis between patients who had 2130 lymph nodes resected and those had 15-20 lymph nodes resected (χ ²=3.924, P<0.05). Significant difference was also observed in the prognosis between patients who had 15-20 lymph nodes resected and those had more than 30 lymph nodes resected (χ ²=4.454, P<0.05), while no significant difference was observed in the prognosis between patients who had lymph nodes resected more than 30 and those had lymph nodes resected less than 15 (χ ²=0.450, P>0.05). The results of univariate analysis showed that gender, age, location and diameter of the tumor, serosal invasion, Borrmann classification, range of gastric resection and the number of lymph nodes dissected were factors influencing the prognosis of patients with low and undifferentiated gastric cancer and with negative metastasis of lymph nodes (χ ²=4.143, 12.607, 23.665, 11.549, 26.350, 8.059, 5.222, 25.077, P<0.05). The results of multivariate analysis showed that the tumor diameter longer than 5 cm and serosal invasion were the independent factors influencing the prognosis of patients with low and undifferentiated gastric cancer and with negative metastasis of lymph nodes (HR=1.842, 3.084, 95% confidence interval: 1.286-2.638, 1.956-4.861, P<0.05). Lymph nodes dissected for 21-30 was the protective factor of prognosis (HR=1.533, 95% confidence interval: 1.229-2.248, P<0.05).
Conclusion:Lymph nodes dissected for 21-30 during radical gastrectomy may improve the longterm survival of patients. The tumor diameter longer than 5 cm, serosal invasion and the number of lymph nodes dissected (less than 15, 15-20 and more than 30) were the independent factors influencing the prognosis of patients with low and undifferentiated gastric cancer and with negative metastasis of lymph nodes.