Endoscopic Recognition and Management Strategies for Malignant Colorectal Polyps: Recommendations of the US Multi-Society Task Force on Colorectal Cancer.

Colorectal polyps are the precursors for most colorectal cancers (CRCs). Some colorectal polyps accumulate enough mutations to develop high-grade dysplasia and eventual invasion of dysplastic elements into the submucosa. The invasion of dysplastic elements into the submucosa constitutes the clinical definition of CRC (Figure 1). The term malignant polyp specifically refers to a colorectal lesion with cancer invading the submucosa but not extending into the muscularis propria. These lesions are classified as pT1 in the TNM classification system. A synonymous and more modern term is submucosally invasive lesion. We will use the nomenclature of submucosal invasion throughout this document interchangeably when referring to a malignant polyp. The prevalence of cancer in colorectal polyps ranges from 0.2% to 5%. Malignant polyps represent the earliest form of clinically relevant CRC in most patients because neoplastic invasion of the submucosa allows for possible lymphatic and vascular metastasis. The risk of metastasis depends on several endoscopic and histologic features. The clinical issue most often raised by malignant polyps is whether a patient with an endoscopically resected colorectal lesion with submucosal invasion requires surgical resection of the colorectal segment from which the lesion was removed. Some malignant polyps can be managed endoscopically because the risk of residual cancer in the bowel wall and/or adjacent lymph nodes is very low. Other endoscopically resected malignant polyps are best managed by surgical resection because endoscopic resection alone is accompanied by a very high risk of residual cancer and/or lymph node metasta-