RESUMO
<p><b>OBJECTIVE</b>To investigate the factors associated with lateral lymph node metastasis in middle and low rectal cancer.</p><p><b>METHODS</b>Clinical data of 203 patients with middle and low rectal cancer (within 10 cm from anal verge) undergoing lateral lymph node dissection in the Affiliated Cancer Hospital, Xinjiang Medical University between June 2004 to June 2010, were analyzed retrospectively. Logistic regression analysis was used to screen the associated factors.</p><p><b>RESULTS</b>The total number of harvested lateral lymph node was 3349, and average number was 17 per case. The number of positive lateral lymph node was 221, and the lymph node metastasis ratio was 6.6%(221/3349). Univariate analysis showed that age, family history, tumor length, gross type of tumor, histological type, differentiation, depth of invasion, invasion of circumference, serum CEA, tumor thrombus and upper lymph node metastasis were associated with rectal cancer metastasis(P<0.05). Multivariate analysis showed that age, histological type, infiltration depth, gross type, differentiation degree and upper lymph node metastasis were the independent risk factors of the lateral lymph node metastasis in middle and low rectal cancer(P<0.05).</p><p><b>CONCLUSION</b>For patients who is young, or with poorly differentiated cancers, infiltrative type, T4 cancer, or those with upper lymph node metastasis, lateral lymph resection may be indicated because of high risk of lateral node metastasis.</p>