Modification of lymph node dissection for colon cancer by clinical diagnosis

Less invasive procedures for colon cancer that are available now increase the needs of modified lymph node dissection. The aim of the present study is to establish oncologically safe criteria for modifying lymph node dissection for colon cancer by clinical diagnosis.

We evaluated the central extent of lymph node metastasis in 276 patients who underwent curative surgery for colon cancer according to clinicopathologic factors and analyzed the accuracy of clinical assessment of the factors.

Only the degree in depth of invasion determined the maximum extent of lymph node metastasis. None of pTis-pT2 tumors showed metastasis to nodes along the main vessels including apical nodes, demonstrating that patients with pTis-pT2, but not pT3-pT4, tumors could be candidates for modified lymph node dissection. While the accuracy in clinical assessment of depth for pTis, pT1, and pT2 tumors was only 59.1%, 73.7%, and 53.6%, respectively, none of the clinically assessed as Tis or T1 tumors was finally diagnosed as a pT3-pT4 tumor. On the other hand, 30.8% of T2 tumors were revealed to be pT3 tumors.

Modification of lymph node dissection by clinical diagnosis should be performed for Tis-T1 but not for T2-T4 tumors when bowel resection is performed.