Investigation of Lymph Node Metastases by Clearing Method Supports Pelvic Plexus Preservation in Rectal Cancer Surgery

摘要

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 feared with these methods, so we examined indications for pelvic plexus preservation. 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 (PRN), and nodes along the middle hemorrhoidal artery lateral to the pelvic plexus and along the internal iliac artery represented lateral intermediate nodes (LIN). Node metastases were examined by the clearing method. Metastasis to PRN occurred in 12.5% in patients with pTl tumors, 28.9% of those with pT2, and 50.0% of those with rectosigmoid junctional cancer. Metastasis to LIN was absent in patients with pTl or pT2 and was as rare as 2.5% in patients with rectosimoid junctional cancer. In patients with Tl, T2 and rectosigmoid junctional cancer, perirectal node dissection is necessary, but chances of residual cancer should remain minimal when the pelvic plexus is preserved.