Medical Care
A full colonoscopy is the accepted procedure of choice in North America for screening or investigation of possible adenomas. If possible, remove all polyps at endoscopy. Send polyps to a pathologist to assess for histological type, grade of dysplasia, and presence of carcinoma. Record the gross morphology, location, and size of each polyp.
Perform a full colonoscopy if sigmoidoscopy reveals an adenoma. Of patients with rectosigmoid adenomas, 40-50% have additional proximal polyps. From the NPS data, patients with left-sided adenomas had a 2.9-fold risk of also having right-sided polyps compared to patients with no left-sided polyps. Patients with only a hyperplastic polyp in the rectosigmoid do not require full colonoscopy.
A variety of polypectomy devices and techniques are available, including snares, biopsy forceps, submucosal injection agents, and ancillary devices. [25] Benefits over saline have been reported on several newer submucosal lifting agents, including lower mean injection volume, shorter procedure times, lower number of resection pieces, higher en bloc resection rates, and decrease in residual lesions. [25]
Cautery snare is recommended for removal of larger polyps. For large sessile polyps, for which the risk of perforation is higher, injection of 1 mL or more of saline or other submucosal lifting agent into the submucosa directly under the polyp is a useful technique. This lifts the flat polyp away from the muscular layer, creating a stalklike effect. A couple of drops of methylene blue added to the saline also allows the operator to determine if a perforation has occurred in the muscle layer, which would be seen as a break in the layer. Smaller sessile polyps should be removed or biopsied and ablated with hot-biopsy forceps or a mini-snare.
After removal of a large (>2 cm) sessile polyp or if the possibility exists of incomplete removal of a large adenoma, a follow-up colonoscopy usually should be performed within 3-4 months.
In the case of malignant polyps, no further treatment is necessary if certain conditions are met, as published by the American College of Gastroenterology:
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The polyp is considered to be completely excised by the endoscopist.
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The polyp is fixed and sectioned so that it is possible to accurately determine the depth of invasion, grade of differentiation, and completeness of excision of the carcinoma.
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The cancer is not poorly differentiated.
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No evidence exists of vascular or lymphatic involvement.
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The margin of the excision is not involved.
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The role for nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors is unclear. No evidence indicates regression in patients who already have polyps who are treated with these agents, although NSAIDS may have a role in primary prophylaxis.
Surgical Care
Surgical resection of a colorectal polyp may be required, especially if the polyp is larger than 2-3 cm and is sessile (as villous adenomas often are). Also, polyps encompassing two colonic folds often require surgical consideration. In such situations, the colonic wall can be marked with India ink for localization of the bowel segment at surgery.
If benign, duodenal villous adenomas can be treated by local transduodenal resection, although recurrence is common and may be malignant. [26] Consider pancreaticoduodenectomy for duodenal malignant villous adenomas and for villous tumors of the ampulla of Vater.
Consultations
A competent endoscopist should supervise care and follow-up.
Consultation with a surgeon may be required for resection of the polyp.
Diet
Dietary recommendations have been established to prevent colorectal cancer. Given the evidence for the adenoma-to-carcinoma sequence, these recommendations likely also apply to adenomas.
Limit total fat to 25-30% of energy intake. A fatty diet may increase biliary sterols, which are damaging.
Increase fruit and fiber intake to 5 servings daily. Increased fiber dilutes luminal contents and decreases the contact between carcinogenic substances and the lumen. Fruits and vegetables also contain minerals and vitamins that may impede carcinogenesis.
Ingest 20-30 g of fiber daily. In addition to the benefits of increased fruit and fiber intake, fiber may inhibit some harmful bacteria and prevent damaging effects of bile acids.
Dietary supplementation with 3 g of calcium carbonate is suggested based upon limited data.
Activity
Recommendations for activity include the following:
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Maintain normal body weight.
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Exercise daily. Exercise helps decrease transit time and, therefore, the contact of harmful substances with the lumen.
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Avoid smoking and excessive consumption of alcohol.
Long-Term Monitoring
Surveillance colonoscopy (after initial colonoscopy and clearing of polyps) is recommended. Note the following [27] :
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Patients with small rectal hyperplastic polyps should be considered to have normal colonoscopies. The interval before the subsequent colonoscopy could be 10 years.
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Patients with 5-10 tubular adenomas, any adenoma ≥1 cm, any adenoma with tubulovillous or villous features, or high-grade dysplasia should have their next follow-up colonoscopy within 3 years.
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Patients who have more than 10 adenomas should be reexamined at a shorter interval (1 y), based on clinical judgment. The clinician should consider the possibility of an underlying familial syndrome.
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Patients with only 3-4 small (< 1 cm) tubular adenomas with only low-grade dysplasia should have their next follow-up colonoscopy probably in 5 years.
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Patients with sessile adenomas that are removed piecemeal should be considered for follow-up evaluation at short intervals (ie, 6 mo) to verify complete removal.
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Villous Adenoma. Endoscopic view of a sessile polyp, which histology studies revealed to be a villous adenoma. Courtesy of H. Chaun, MD.
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Villous Adenoma. Endoscopic view of a sessile polyp histologically determined to be a villous adenoma. Courtesy of R. Enns, MD.
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Villous Adenoma. Endoscopic view of injection of saline into the base of a sessile polyp histologically determined to be a villous adenoma. This enables an easier polypectomy. Courtesy of R. Enns, MD.
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Villous Adenoma. Polypectomy with a snare around a sessile polyp base (villous adenoma) injected with saline. Courtesy of R. Enns, MD.
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Villous Adenoma. Histology of villous adenoma. Fingerlike projections stretching from the surface of a polyp downward with minimal branching. Courtesy of D. Owen, MD.
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Villous Adenoma. Histology of villous adenoma. Low-grade dysplasia with loss of mucin, prominent nucleoli, and hyperchromatic and elongated cells. Courtesy of D. Owen, MD.
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Villous Adenoma. Fecal occult blood testing. Video courtesy of Therese Canares, MD; Marleny Franco, MD; and Jonathan Valente, MD (Rhode Island Hospital, Brown University).
