Large sessile colonic adenomas: use of argon plasma coagulator to supplement piecemeal snare polypectomy

Background: Residual adenoma is frequently found at the site of endoscopically resected large sessile adenomas on follow-up examination. We evaluated the efficacy of a thermal energy source, the argon plasma coagulator, to destroy visible residual adenoma after piecemeal resection of sessile polyps. Methods: Seventy-seven piecemeal polypectomies with or without the use of argon plasma coagulator were analyzed retrospectively. All polyps were sessile, 20 mm or greater in size. The results from three groups of patients were compared. The study group was composed of patients who had visible residual adenoma after piecemeal polypectomy and had the base of the polypectomy site treated with the argon plasma coagulator. The first comparison group consisted of patients who underwent standard piecemeal polypectomy in whom the colonoscopist thought that all adenomatous tissue was removed and no further treatment was necessary. The second comparison group included patients in whom visible residual adenoma was left at the base after piecemeal resection of large adenomas. Follow-up colonoscopy was performed approximately 6 months after the initial procedure to check for recurrent/residual adenomatous tissue. Results: The argon plasma coagulator was used after 30 piecemeal polypectomies in an attempt to eradicate visible residual adenomatous tissue; at follow-up, 50% of these cases had complete eradication of adenoma. The group in whom all visible tumor was removed by piecemeal polypectomy alone had an adenoma eradication rate of 54% on follow-up colonoscopy. In the patients in whom visible residual adenoma was left at the site the recurrence rate was 100% on the follow-up examination. Bleeding necessitating endoscopic therapy occurred once (3.3%) in the argon plasma coagulator group; there were four (12.5%) bleeding episodes and one (3.1%) confined retroperitoneal perforation in the complete piecemeal polypectomy group and no complications in the group in which polypectomy was incomplete. Conclusions: Argon plasma coagulator ablation of residual adenomatous tissue at the polypectomy base is safe and useful. It helps to complete the eradication of large sessile polyps when there is visible evidence of residual polyp.