OBJECTIVETo explore the risk factors associated with the prognosis in poorly differentiated(G3) advanced gastric cancer (AGC) and the effect of number of harvested lymph nodes on the prognosis.

METHODSClinical data of 484 patients with G3 advanced gastric cancer undergoing gastrectomy combined with lymphadenectomy in Zhongshan Hospital from December 2002 to October 2007 were retrospectively analyzed. The χ(2) test or Fisher's exact probability method was used to test measurement data. Survival was calculated using Kaplan-Meier method. Clinicopathological factors such as age, invasion depth, number of harvested lymph nodes, lymph node metastasis, ratio of metastatic lymph node, lymphatic vessels involvement were analyzed using the Cox regression model.

RESULTSNumber of lymph node dissected, lymph node metastasis, ratio of metastatic lymph node and lymphatic vessels involvement were significantly affected by groups of 15 lymph node dissected in G3 AGC patients (P<0.05). Invasion depth, number of lymph node dissected, lymph node metastasis, ratio of metastatic lymph node and lymphatic vessels involvement were significantly independent predictors of survival in G3 AGC patients (all P<0.05). Patients with at least 20 lymph nodes had a better survival rate than those with less than 20(P<0.01).

CONCLUSIONSInvasion depth, number of harvested lymph nodes, lymph node metastasis, ratio of metastatic lymph node and lymphatic vessels involvement are important factors influencing the prognosis of G3 AGC. At least 20 lymph nodes should be recommended to ensure the quality of lymphadenectomy for gastric cancer.