Large Colorectal Polyps: Endoscopic Resection And Rate Of Malignancy. Does Size Matter?

Background: Large colorectal polyps (LCP) (> 2 cm) are uncommon. There is scant data published in regard to rate of malignancy and safety/success of endoscopic resection. This study was performed to evaluate the relationship between LCP and malignancy as well as to evaluate the safety and efficacy of endoscopic resection. Methods: All colonoscopies performed by two experienced endoscopists between July 2002 to December 2005 at our institution were reviewed and LCPs were identified. Characteristics of the polyp (morphology, size, location, and inability to lift with submucosal injection), methods of resection, adjunct therapy (i.e. APC), pathology results, complications and follow up colonoscopy were recorded. Results: 96 LCPs were removed from 88 patients. Saline assisted polypectomy was used in all sessile polyps. Non lifting polyps were not removed. Monopolar coagulation or “endocut” settings were used. 79% of polyps were sessile. The ascending colon was the most common site (24%). Retroflexion was employed to assist polypectomy in ∼ 19% of polyps. 6.25% of polyps required multiple colonoscopic sessions. 18.8% of polyps were malignant, of these 50% were intramucosal and the rest were invasive. 8 of the 9 invasive carcinoma polyps were sessile. Polyps ≥ 4 cm in size had a 2.5 times the likelihood of malignancy compared to polyps between < 40 mm. The majority of polyps were tubulovillous or villous adenoma. Ten patients (10.4%) experienced post polypectomy bleeding however none required transfusion. Three had immediate bleeding which was controlled with endoclips. Four of the seven with delayed bleeding required colonsocopic intervention. Three patients (3.1%) suffered a perforation with one managed with immediate endoscopic closure with endoclips. Two patients had surgery. There were no deaths observed. Complete polypectomy was successful in 96.2% of polyps excluding those with invasive cancer. Eleven patients required surgery for their polyps (11%); eight because of invasive cancer and 3 secondary to incomplete polypectomy. Ten patients (10.4%) had evidence of residual polyp on 1st follow up colonoscopy after assumed complete resection. Conclusions: Most large polyps are benign and can be removed endoscopically. However, the risk of bleeding and perforation is higher than smaller polyps. This increased risk is likely due to the high percentage of right sided lesions (56.3%).