A 61-year-old man comes to the office for follow-up after a screening colonoscopy. During the procedure, a 1-cm pedunculated polyp in the sigmoid colon and 2 small pedunculated polyps in the descending colon were removed. Histopathologic evaluation of the sigmoid lesion revealed an adenomatous polyp with an area of well-differentiated adenocarcinoma invading the muscularis mucosa in the head of the polyp. The stalk and the polyp margins are free of cancerous tissue. No lymphatic or vascular involvement is seen in the tissue sample. The two descending colon polyps are hyperplastic. The patient previously had a normal screening colonoscopy at age 50 and has no family history of colon cancer. Which of the following is the most appropriate next step in management of this patient?

Question

A 61-year-old man comes to the office for follow-up after a screening colonoscopy.  During the procedure, a 1-cm pedunculated polyp in the sigmoid colon and 2 small pedunculated polyps in the descending colon were removed.  Histopathologic evaluation of the sigmoid lesion revealed an adenomatous polyp with an area of well-differentiated adenocarcinoma invading the muscularis mucosa in the head of the polyp.  The stalk and the polyp margins are free of cancerous tissue.  No lymphatic or vascular involvement is seen in the tissue sample.  The two descending colon polyps are hyperplastic.  The patient previously had a normal screening colonoscopy at age 50 and has no family history of colon cancer.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This patient has sigmoid colon adenocarcinoma confined within a polyp. Adenocarcinoma usually develops within an adenomatous polyp but often extends beyond the polyp at the time of diagnosis. However, confinement within a polyp with confirmed clear margins greatly simplifies management. Surgical resection is necessary for most colorectal adenocarcinomas, but endoscopic treatment with polypectomy is adequate for lesions without submucosal invasion (ie, carcinoma in situ). Minimally invasive lesions confined to a pedunculated polyp can also be safely managed with polypectomy if there are clear margins (ie, absence of malignant cells at the specimen edge) and low-risk histopathology findings (eg, well-differentiated features, no lymphovascular invasion). Poorly differentiated lesions and those with extension to the margin of the resected polyp typically require surgery (eg, colectomy) (Choice D). Regardless of treatment modality, close colonoscopic surveillance (eg, no later than 1 year) after resection is indicated. (Choices B and E) Postoperative radiation therapy is commonly used in management of rectal adenocarcinoma, largely due to difficulty in achieving adequate tissue margins. Chemotherapy may be used in neoadjuvant, adjuvant, or palliative regimens in patients with stage IV (eg, distant metastasis) colon adenocarcinoma. However, neither treatment is needed for this patient's completely resected sigmoid lesion with clear margins. (Choice C) Right-sided hemicolectomy is not indicated because no polyps were identified in the right colon. Educational objective: Well-differentiated adenocarcinoma confined to a pedunculated colonic polyp without involvement of the stalk or resection margins can be managed with endoscopic removal followed by close colonoscopic surveillance. References: Endoscopic recognition and management strategies for malignant colorectal polyps: recommendations of the US Multi-Society Task Force on Colorectal Cancer. (http://www.ncbi.nlm.nih.gov/pubmed/33159840)

A 61-Year-Old Man Comes to the Office for Follow-Up After