The US Multi-Society Task Force on Colorectal Cancer has published new recommendations for endoscopists on how to manage patients with colorectal lesions. The guidelines, jointly published in Gastroenterology, the American Journal of Gastroenterology, and Gastrointestinal Endoscopy, address how to assess lesions for endoscopic features associated with cancer, how these factors guide endoscopic management, and the factors that frame whether to advise surgery after a malignant polyp has been endoscopically resected.
The US Multi-Society Task Force on Colorectal Cancer, which comprises leading researchers from the American College of Gastroenterology (ACG), the American Gastroenterological Association (AGA), and the American Society for Gastrointestinal Endoscopy (ASGE), defines a “malignant polyp” as “a colorectal lesion with cancer invading the submucosa but not extending to the muscularis propria.” All recommendations presented are rated by 1 of 4 evidence quality categories: high, moderate, low, or very low.
The task force organized its report according to key questions that address the following 3 clinical scenarios:
- Endoscopic recognition of colorectal polyps with deep submucosal invasion that should be referred directly to surgery;
- Optimal endoscopic resection techniques and specimen handling when an increased risk of superficial submucosally invasive polyp is identified; and
- Weighing the risks and benefits of surgery when an endoscopically removed polyp is found to have submucosal invasion.
The first inquiries that the task force addresses in the report concern the endoscopic features in a colorectal polyp that predict deep submucosal cancer, and how nonpedunculated and pedunculated polyps should be managed when deep submucosal cancer is suspected. In these instances, the task force recommends the following:
- Recommendation 1a: Pedunculated and nonpedunculated polyps with NBI International Colorectal Endoscopic (NICE) classification type 3 or Kudo classification of type V (VN and VI) should be considered to have deep submucosal invasion. (Strong recommendation; high-quality evidence)
- Recommendation 1b: Nonpedunculated lesions with these features should be biopsied (in the area of surface feature disruption), tattooed (unless in or near the cecum), and referred to surgery. Pedunculated polyps with features of deep submucosal invasion should undergo endoscopic polypectomy. (Weak recommendation; low-quality evidence)
“When nonpedunculated lesions with NICE 3 or Kudo VN features are encountered, biopsy should be directed to the region of surface feature disruption, tattooed if not in or near the cecum, and the patient directed to surgery,” the task force stated. “NICE 3 and Kudo VN features are often associated with surface ulceration and irregularity.”
The task force also advises that all pedunculated lesions be resected en bloc through the stalk and bivalved though the polyp head and stalk by pathology. “An accurate histologic diagnosis is key to accurate staging and management,” the group said.
The second question addresses the endoscopic features that predict the risk of superficial submucosal invasion in a sessile polyp and the optimal endoscopic method of resection for sessile and pedunculated malignant polyps with superficial submucosal invasion.
- Recommendation 2a: Nongranular lateral spreading tumors (LST-NG) morphology with sessile shape or depression and granular lateral spreading tumors (LST-G) with a dominant nodule predict a higher risk of submucosally invasive cancer. (Weak recommendation; moderate-quality evidence)
- Recommendation 2b: Such lesions should be considered for en bloc endoscopic resection instead of piecemeal resection when feasible (and based on local expertise). In the case of LST-G with a dominant nodule, at least the nodular area should be considered for en bloc resection. All pedunculated polyps, even if large, should be resected en bloc. (Weak recommendation; low-quality evidence)
The endoscopic features associated with an increased risk for superficial submucosal invasion in the absence of endoscopic features of deep submucosal invasion include LST-NG morphology (especially if there is depressed shape) and LST-G morphology with dominant nodules.
“Although endoscopists should be aware of endoscopic features associated with superficial submucosal invasion and the rationale for en bloc resection, the actual approach to endoscopic resection will reasonably take into account lesion size, morphology, location in the colon, and the availability of local expertise and resources to accomplish en bloc resection,” the task force stated.
The third question focuses on whether polyp specimens with features suggestive of submucosal invasive cancer that are resected en bloc should be prepared for pathologic submission. According to the task force, these specimens should be handled in ways to optimize specimen orientation and pathologic evaluation (Weak recommendation; low-quality evidence).
Further, a request to pathology should include the location, size, and morphology (sessile vs pedunculated) of the polyp. “Polyps that are resected en bloc with an increased risk of cancer should be pinned to a firm surface before submersion in formalin and sectioned in pathology perpendicular to the plane of endoscopic resection,” the group stated.
The guidance next addresses the histologic features in nonpedunculated malignant polyps associated with lymph node metastasis and an increased risk of local or regional recurrence. The task force also discusses which histologic features in pedunculated malignant polyps correlate with lymph node metastasis and an increased risk of local or regional recurrence.
- Recommendation 4a: Nonpedunculated malignant polyps should be considered high-risk for residual or recurrent cancer if they have any of the following features: poor tumor differentiation, lymphovascular invasion, submucosal invasion depth of more than 1 mm, tumor involvement of the cautery margin, or tumor budding. (Strong recommendation; moderate evidence)
- Recommendation 4b: Pedunculated malignant polyps should be considered at high-risk of residual or recurrent cancer if they have any of the following features: poor tumor differentiation, lymphovascular invasion, or tumor within 1 mm of the resection margin. (Strong recommendation; moderate evidence)
“Identifying features associated with lymph node metastasis (LNM), both endoscopically and histologically, is very important as it helps inform which patients should undergo surgery,” the task force noted.
The set of recommendations also broaches pathology reporting standards for malignant colorectal polyps. Specifically, the task force advises that
pathology reports adhere to the recommendation of the College of American Pathologists structured template. They should also contain the histologic type, grade of differentiation, tumor extension/invasion, stalk, and mucosal margin status, as well as the presence or absence of lymphovascular invasion. The task force suggests that other aspects such as specimen integrity, polyp size, polyp morphology, and tumor budding be included. (Weak recommendation; low-quality evidence)
“An organized, consistent system of reporting histopathology findings is essential for improving the quality of post-polypectomy decision-making,” the task force stated. A number of reporting techniques have been proposed, including adopting structured checklists as a standardized practice to reduce the chance of omissions and minimize misinterpretations, which is expected to further streamline reporting across hospitals and practice groups.
The final question that the task force canvasses concerns those who should be involved in the multidisciplinary management of patients with malignant polyps. The task force members suggest that methods of communication among the gastroenterologist, pathologist, oncologist, surgeon, and the patient be established (weak recommendation; low-quality evidence).
“Interdisciplinary cooperation among the gastroenterologist, pathologist, oncologist, and surgeon is highly desirable, as there are multiple steps required in diagnosing, assessing, and providing definitive treatment,” the group stated. “The multidisciplinary approach can involve the patient’s primary care provider and other medical specialists (eg, a cardiologist), particularly in cases where the patient’s comorbid disease might be significant and life expectancy is decreased.”
Overall, the optimal approach for managing patients with malignant polyps begins with a thorough endoscopic assessment that identifies the features of deep submucosal invasion, according to the task force.
“In nonpedunculated lesions with features of deep submucosal invasion, endoscopic biopsy is followed by surgical resection,” the group concluded. “In cases without features of deep submucosal invasion, en bloc resection and proper specimen handling should be considered (if feasible) for lesions with a high risk of superficial submucosal invasion. When pathology reports cancer in a lesion that was completely resected endoscopically, the decision to recommend adjuvant surgery is based on polyp shape, whether there was en bloc resection and adequate histologic assessment, the presence or absence of unfavorable histologic features, the patient’s risk for surgical mortality and morbidity, and patient preferences.”
Shaukat, Kaltenbach T, Dominitz JA, et al. Endoscopic recognition and management strategies for malignant colorectal polyps: recommendations of the US Multi-Society Task Force on Colorectal Cancer.Gastroenterology. 2020;159(5):1916-1934.e2. doi: 10.1053/j.gastro.2020.08.050