Nodal drainage pathways in primary rectal cancer: anatomy of regional and distant nodal spread.

Nodal involvement is a significant prognostic factor in rectal cancer and difficult to assess preoperatively. An understanding of the patterns of nodal spread from different regions of the rectum can assist in this process and is essential for the purposes of surgical planning. In this article we define patterns of spread to mesenteric and pelvic sidewall nodal subgroups and discuss the importance of accurate anatomic localization of nodes for the purposes of staging and surgical planning.