A Comprehensive Review on Recent Advances in Management, Presentation, and Pathophysiology of Rectal Neuroendocrine Tumors

Abstract

A rectal neuroendocrine neoplasm (r-NEN) is one of the most common digestive NENs, along with a small bowel NEN. Due to the widespread use of endoscopic screening for colorectal cancer and the advanced endoscopic procedures available today, their incidence has increased in the past few years. In view of their low risk of local or distant invasion, well-differentiated r-NENs smaller than 10 mm should be endoscopically removed. Because r-NENs larger than 20 mm may spread distantly and involve the muscularis propria, they should be surgically resected. Metastasis risk is intermediate for tumors between 10 and 20 mm, and endoscopic treatment can be challenging for these tumors. A possible algorithm is proposed here based on the limited and poorly codified indications for surveillance once a patient has been removed.