The Malignant Polyp Handout Version Hans Elzinga, MD Program Director- Advanced Procedures in Family Medicine Fellowship Salud Family Health Center-Longmont, CO

Objectives Understand the definition of the malignant polyp, related pathology reports, and potential varying terminology Recognize the potential malignant polyp endoscopically, and plan accordingly for initial best management, including strategies for removal and tagging Manage the malignant polyp according to evidence-based guidelines, including proper referral and surveillance recommendations

Alternative Nomenclature Tis Intramucosal Adenocarcinoma Intramucosal Cancer Carcinoma In Situ Severe Dysplasia High-Grade Dysplasia (preferred)

Definition of Malignant Polyp A polyp with cancer invading through the muscularis mucosae, (pT1) into the submucosa Note: pTis is not considered a “malignant polyp” – no biological potential to metastasize ICD (Carcinoma In Situ of Colon)

Surveillance Recommendations for pTis Patients with 3-10 adenomas, or any adenoma >1cm, or any adenoma with villous features, or high-grade dysplasia should have their next follow-up colonoscopy in 3 years providing that piecemeal removal has not been done and the adenoma(s) are completely removed If the follow-up colonoscopy is normal or shows only one or two small tubular adenomas with low-grade dysplasia, the the interval for the subsequent examination should be 5 years

Follow-up pTis of Sessile Polyp Removed Piecemeal or ? Complete Resection Repeat colonoscopy within 3-6 months If residual tissue is identified, this should be removed with repeat colonoscopy in 3-6 mo. If a polyp cannot be completely removed within 1-3 examinations, surgery is recommended

Pathologic pTNM Classification Primary Tumor (T) TX: Cannot be assessed T0: No evidence of primary tumor Tis: Carcinoma in situ, intraepithelial or invasion of lamina propria/muscularis mucosae T1: Tumor invades submucosa T2: Tumor invades muscularis propria T3: Tumor invades through the muscularis propria into pericolorectal tissues T4a: Tumor penetrates the visceral peritoneum T4b: Tumor directly invades or is adherent to other organs or structures Regional Lymph Nodes (N) NX: Cannot be assessed N0: No regional lymph node metastasis N1a: Metastasis in 1 regional lymph node N1b: Metastasis in 2 to 3 regional lymph nodes N1c: Tumor deposit(s) in the subserosa, or non-peritonealized pericolic or perirectal tissues without regional lymph node metastasis N2a: Metastasis in 4 to 6 regional lymph nodes N2b: Metastasis in 7 or more regional lymph nodes Distant Metastasis (pM) MX: Distant metastasis cannot be assessed M0: No distant metastasis M1: Distant metastasis M1a: Metastasis to single organ or site (eg, liver, lung, ovary, nonregional lymph node) M1b: Metastasis to more than 1 organ/site or to the peritoneum

T1-Who may not need referral 1)Single specimen 2)Completely removed (clean margin) 3)Favorable histologic features-no angiolymphatic invasion, grade 1 or 2

Risk factors for polyps with high-grade dysplasia or cancer Villous histology (20-30% of polyps >1cm) Larger polyps (>2cm, 20% risk of cancer) Increased age of patient Increased number of polyps (24% risk of advanced pathology if h/o >5 adenomas at baseline colonoscopy) Use narrow band if available to anticipate path

pT1-Pedunculated vs. Sessile Sessile - Observation may be considered, with the understanding that there is significantly greater incidence of adverse outcomes Pedunculated polyps with cancer confined to the submucosa and without evidence of unfavorable histologic factors have a 0.3% risk of cancer recurrence or lymph-node metastasis after complete removal vs. 4.8% for similar sessile polyps

Malignant Polyp pT1 Fragmented Polyp => colectomy Margin Cannot be Assessed => colectomy Unfavorable Histologic Features => colectomy (grade 3 or 4, angiolymphatic invasion, positive margin of resection (presence of tumor within 1-2mm from the transected margin, or the presence of tumor cells within the diathermy of the transected margin))

Summary Tis – Completely resected => repeat in 3y, then 5y – Incomplete => repeat in 3-6 months T1 – Pedunculated, completely resected => 1y – Sessile, completely resected => 1y or surgery – Fragmented, ? margin, positive margin, unfavorable histology => surgery

Bibliography National Comprehensive Cancer Network Guidelines Version Colon Cancer Guidelines for Colonoscopy Surveillance after Screening and Polypectomy: A Consensus Update by the US Multi-Society Task Force on Colorectal Cancer (Gastroenterology 2012;143: ) ASGE guideline: the role of endoscopy in the diagnosis, staging, and management of colorectal cancer (Gastrointestinal Endoscopy 2005;61:1-7)