OBJECTIVETo discuss the impact of number of retrieved lymph nodes and lymph node ratio(LNR) on the prognosis in patients with stage II and III colorectal cancer.

METHODSClinicopathological data of 507 patients with stage II and III colorectal cancer were analyzed retrospectively. Follow-up was available in all the patients.

RESULTSThe total number of retrieved lymph nodes was 5801, of which 1122 had metastasis. There was a positive correlation between metastatic lymph nodes and retrieved lymph nodes(r=0.171, P<0.01). In stage II colorectal cancer there was a significant difference in 5-year survival rate between patients with more than 12 lymph nodes retrieved and those with less than 12 lymph nodes retrieved(P<0.01). LNR also affected the 5-year survival rate of patients with stage II and III colorectal cancer(P<0.05). In patients with similar LNR, the 5-year survival rate differed significantly among different regions of lymph node metastasis(P<0.05). LNR influenced the prognosis independent of the number of lymph nodes retrieved.

CONCLUSIONSThe number of retrieved lymph nodes is a prognostic factor for stage II and III colorectal cancer. More than 12 lymph nodes should be retrieved for better staging and prognosis. LNR is also a prognostic factor in stage II and III colorectal cancer. Regions of lymph nodes metastasis should be considered when evaluating the prognosis of patients using LNR.