PURPOSE: On the basis of a retrospective review, we aimed to clarify the optimum extent of lymph node dissection in patients with cT1 and cT2 colorectal cancer. METHODS: We reviewed medical records of 487 patients with cT1 and 351 patients with cT2 colorectal tumors, who had undergone curative surgery. RESULTS: In patients with cT1 tumors, results of pathologic examination showed either no lymph node metastasis or metastasis within the paracolic or pararectal region in 284 (98.3 percent) of 289 patients with colon tumors and 195 (98.5 percent) of 198 with rectal tumors. Of 459 patients without clinically evident metastasis, only one patient with a poorly differentiated adenocarcinoma had metastasis beyond the paracolic area. In 28 patients with cT1 tumors and clinically diagnosed node metastasis, pathologic examination showed that node involvement did not extend beyond the named vessel in 26. Among patients with cT2tumors, 97.5 percent of patients with colon tumors and 95.9 percent with rectal tumors had no or limited metastasis. Of 276 without clinically evident metastasis, none had node metastasis at the roots of the named vessels; of 75 with clinically evident metastasis, none had pathologic extension beyond the roots of the named vessels. CONCLUSIONS: In cT1 patients with cN-negative colorectal cancers, paracolorectal lymph node dissection may be optimal; in those with cN positivity, the regional nodes along the named vessels should be dissected. In cT2 patients who are cN-negative, dissection of the regional nodes may be optimal. For those with cN positivity, dissection at the roots of the named vessels should be considered.
PURPOSE: On the basis of a retrospective review, we aimed to clarify the optimum extent of lymph node dissection in patients with cT1 and cT2colorectal cancer. METHODS: We reviewed medical records of 487 patients with cT1 and 351 patients with cT2colorectal tumors, who had undergone curative surgery. RESULTS: In patients with cT1tumors, results of pathologic examination showed either no lymph node metastasis or metastasis within the paracolic or pararectal region in 284 (98.3 percent) of 289 patients with colon tumors and 195 (98.5 percent) of 198 with rectal tumors. Of 459 patients without clinically evident metastasis, only one patient with a poorly differentiated adenocarcinoma had metastasis beyond the paracolic area. In 28 patients with cT1tumors and clinically diagnosed node metastasis, pathologic examination showed that node involvement did not extend beyond the named vessel in 26. Among patients with cT2tumors, 97.5 percent of patients with colon tumors and 95.9 percent with rectal tumors had no or limited metastasis. Of 276 without clinically evident metastasis, none had node metastasis at the roots of the named vessels; of 75 with clinically evident metastasis, none had pathologic extension beyond the roots of the named vessels. CONCLUSIONS: In cT1patients with cN-negative colorectal cancers, paracolorectal lymph node dissection may be optimal; in those with cN positivity, the regional nodes along the named vessels should be dissected. In cT2patients who are cN-negative, dissection of the regional nodes may be optimal. For those with cN positivity, dissection at the roots of the named vessels should be considered.