Distal dissection in total mesorectal excision, and preoperative chemoradiotherapy and lateral lymph node dissection for rectal cancer.

The local recurrence rate after total mesorectal excision (TME) appears to be markedly lower than that after conventional operations. We reviewed all relevant articles identified from the MEDLINE databases and clarified the rationale for TME. It is clear that distal intramural spread is rare. Even when present, such spread is not likely to extend beyond 2 cm. Data with attention to mesorectal cancer deposits suggest that mesorectal clearance of at least 4-5 cm distal to the tumor should be sufficient. TME should be performed for most tumors of the mid- and lower rectum. This does not mean that the gut tube needs to be divided at the same level in every case. Dissection of the distal mesorectum off the gut tube can be performed, so the distal line of division of the bowel wall can be made at a minimum of 2 cm below the tumor if such a maneuver would ensure that the sphincters are preserved. In cases with cancer in the upper third of the rectum, the mesorectum and gut tube can safely be divided 5 cm below the tumor without jeopardizing the recurrence rates. Our findings indicate that TME is an essential treatment approach for rectal cancer, and lateral lymph node dissection and preoperative chemoradiotherapy are additional therapies that should be considered for advanced rectal cancer.