RESUMEN
Lateral lymphatics of the rectum originate in the area where branches of the inferior hypogastric plexus and the middle rectal vessels from the internal iliac vessels enter the mesorectum below the level of the peritoneal reflection in the pelvis, then reach the bifurcation of iliac vessels along the internal iliac vessels. Among lateral lymph nodes, the middle rectal, obturator, and internal iliac lymph nodes are important from the viewpoint of both the incidence of metastais and treatment effects. Although total mesorectal excision (TME) had become the standard surgical treatment for rectal cancer by the 1990s, this technique does not treat lateral node metastasis. A randomized clinical trial of TME versus D3 lymphadenectomy (JCOG0212) was started in 2003, and the registration of 701 patients with lower rectal cancer was completed in August 2010. The results of this clinical trial are highly anticipated. In Japan, where the rate of local recurrence after surgery is low, patients at high risk of local recurrence such as those with lateral node metastasis, T4 disease, and multiple lymph node metastases in the mesorectum should be selected to receive preoperative chemoradiation. Japanese surgeons who treat rectal cancers are in an advantageous position because they have the additional measure of lateral node dissection along with TME and chemoradiotherapy.