Examination of nodal metastases by a clearing method supports pelvic plexus preservation in rectal cancer surgery

PURPOSE: In rectal cancer surgery preservation of urinary and sexual function is attempted by means of operations preserving the autonomic nerves of the pelvic plexus. Emergence of residual cancer because of a more shallow plane of dissection is a problem of concern with these methods, so we examined indications for pelvic plexus preservation. METHODS: We studied 198 patients with rectal carcinoma who underwent abdominopelvic lymphadenectomy. Lymph nodes along the superior hemorrhoidal artery and middle hemorrhoidal artery medial to the pelvic plexus were defined as perirectal nodes, and nodes along the middle hemorrhoidal artery lateral to the pelvic plexus and along the internal iliac artery represented lateral intermediate nodes. Node metastases were examined by the clearing method. RESULTS: Metastasis to perirectal nodes occurred in 12.5 percent in patients with pT1 tumors, 28.3 percent-of those with pT2 tumors, and 50.0 percent of those with rectosigmoid junctional cancer. Metastasis to lateral intermediate nodes was absent in patients with pT1 or pT2 tumors and was as low as 2.5 percent in patients with rectosigmoid junctional cancer. CONCLUSIONS: In patients with T1, T2, and rectosigmoid junctional cancer, perirectal, node dissection is necessary, but chances of residual cancer should remain minimal when the pelvic plexus is preserved.