Background: Large colonic polyps present a particular challenge to endoscopists because of the risks of significant haemorrhage, perforation, inadequate polypectomy, or trying to snare an unrecognized cancer. The alternative to endoscopic therapy of large polyps is surgical resection and although minimally invasive techniques are available, risks are significant. Although neither surgery nor endoscopy is a perfect way of treating large colonic polyps, endoscopic resection is usually tried first. Most series of endoscopic polypectomies are small, include both rectal and colonic polyps and have varying size and shape criteria. The purpose of the present study is to describe a large consecutive series of colonic polyps evaluated endoscopically, to determine the chances of performing a safe, effective endoscopic polypectomy.
Methods: All colonic polyps>20 mm in maximum dimension assessed during colonoscopy from 1989 to 2002 were reviewed. Rectal polyps were excluded. Demographic data for the patients were abstracted, as were data regarding the outcomes of polyp assessment and treatment. Primary end-points were: the need for surgical resection, the incidence of postpolypectomy complications and the persistence of the index polyp at follow up. Independent variables included the endoscopically assessed size of the polyps, the year in which the polypectomy took place, the shape of the polyps and their location within the colon.
Results: During the period under review 311 large polyps were removed from 252 different patients. Of these, 263 polyps were removed endoscopically and 48 polyps were removed surgically. An additional 18 endoscopically removed polyps ultimately needed surgery for recurrence or malignancy. There were no deaths but 19 complications of endoscopic polypectomy (17 late haemorrhage and two postpolypectomy syndrome). At first follow up, 22% of polyps had persisted, this decreased to 14% at second follow up and 7% at third. Complications were more common in right sided polyps and in flat or sessile lesions. Pedunculated polyps never persisted or recurred and had the lowest rate of surgery. Larger polyps had higher rates of advanced histology, complications, polyp persistence and the need for surgery.
Conclusions: Polyp size, location and shape influence the results of endoscopic resection of large colonic polyps. Polyps>30 mm in maximum diameter are significantly more advanced histologically but also significantly more difficult to treat successfully than those <30 mm. However, size alone is rarely a contraindication to endoscopic resection.