Outcomes Following Referral for Colonoscopic Resection of the “Defiant Polyps”: A Single Center Experience

Abstract

Purpose: Flat and sessile lesions are being identified with increasing frequency owing to increased awareness and enhanced imaging. The “defiant polyp” [DP] is a lesion identified at colonoscopy that defies resection by standard snare polypectomy technique. Increasingly, the DP undergoes photodocumentation, tissue sampling and is referred for subsequent curative colonoscopic resection. The aim of this study was to detail the current nature of the DPs and outcomes with referral for curative colonoscopic resection. Methods: The indication term “defiant polyp” was ascribed prospectively as defined above beginning June ‘07. An electronic endoscopy report data set was searched for this indication from June’07 to Sept'09 for a single endoscopist at a tertiary center. Data pertaining to patient age and gender, polyp site and histopathology, resection technique, use of adjunctive ablation, adverse events, and residual/recurrent neoplasia at follow up were culled. Patients underwent resection following submucosal injection of varying quantities of normal saline solution tinted with Methylene blue dye. Standard and min-snares were used with pure coagulation current. Results: Two hundred seventy six patients (50.4% Female, age 65; SD12) with a total of 302 DP were identified for resection. The morphology of DPs according to Paris classification was Ip 22, Is 196, IIa 82, IIb 2. The majority of DPs were located in the right colon (218; 72%). The mean size was estimated as 23 mm (8-100 mm, SD12). In 29 (9.6%), endoscopic resection was deemed unsuitable due to unfavorable appearance (7), access (12), or non-lifting (10). Endoscopic complete eradication (R0) was achieved in a single session in 268 of DPs (98.2%). Five polyps required up to 3 additional sessions for R0. En bloc resection was done in 146 polyps (53.5%)and piecemeal in 126 (46.2%). Histopathology revealed 173 tubular adenomas (61.1%), 57 serrated adenomas (20.1%), 26 tubulo-villous adenomas (9.2%), 17 hyperplastic polyps (6%) and 10 adenocarcinomas (3.5%). Adjunctive ablation of focal residual neoplastic tissue was applied in 66 cases (24.2%) to achieve R0. Procedure related adverse events were recorded in 22 (9.5%) of 231 patients. Acute bleeding occurred in 7 patients (one required hospitalization and repeat endoscopy). There was one microperforation managed with clip closure and antibiotics. Delayed bleeding (1 to 6 days post procedure) was observed in 14 patients (6.1%) of whom 8 patients required hospitalization and 4 patients colonoscopy for haemostasis. Conclusion: DPs consist predominantly of sessile and flat adenomas including serrated adenomas. Most DPs can be successfully eradicated at dedicated therapeutic colonoscopy using adjunctive resection and ablation techniques. The R0 rate is high and adverse events are low.