RESUMEN
<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Clinicopathological data of 507 patients with stage II and III colorectal cancer were analyzed retrospectively. Follow-up was available in all the patients.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSIONS</b>The 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.</p>