Management of Locoregional Rectal Cancer.

The NCCN Guidelines for Rectal Cancer are now more closely aligned with those for colon cancer. A new MRI-based definition of the rectum has been included and the use of MRI in staging has been elevated in importance. There is a new emphasis on neoadjuvant therapy, especially the concurrent use of chemotherapy and radiotherapy. One of the biggest changes is more acceptance of an observational approach-"watch and wait, nonoperative management"-for select patients experiencing a complete clinical response with no evidence of residual disease after neoadjuvant therapy.