Tu1342 Outcomes of Endoscopic Mucosal Resection (EMR) of Large Polyps (≥ 20 mm) Detected in a Colorectal Cancer Screening Program

Outcomes of Endoscopic Mucosal Resection (EMR) of Large Polyps (> 20 mm) Detected in a Colorectal Cancer Screening Program Xavier Bessa*, Alvaro Diaz-Gonzalez, Maria Pellise, Joana Villaverde, ineS D. SimoES, Cristina Hernandez, Francesc Macia, Merce PiraceS, Jaume Grau, Anna Serradesanferm, M. Angeles Pozo Fernandez, Josep Llach, Luis E. Barranco, Cristina Alvarez, Antoni Castells, Montserrat Andreu Hospital del Mar, Barcelona, Spain; Hospital Clinic, Barcelona, Spain Implementation of colorectal cancer screening programs has increased the detection of large polypoid lesions. These lesions have a higher risk of malignancy, and a complete resection followed by an adequate surveillance is required. Objective: To evaluate the treatment and outcomes of large polyps detected in an average-risk population undergoing colorectal cancer screening. Methods: All polyps 20 mm detected in the first round of a CRC screening program (asymptomatic men and women aged 50 to 69 years) were evaluated retrospectively. Patients with synchronous CRC or polyposis syndromes were excluded. We collected data about clinical and endoscopic characteristics (size [20-29 vs 30 mm], location [rectal, left and right colon], morphology [sessile or flat vs pedunculated] and lateral extension), histopathology, resection technique (en bloc vs piecemeal), and presence of residual/recurrent neoplasia at follow-up. Results: 483 polyps 20 mm (444 adenomas, 8 hyperplastic, 10 serrated polyps and 21 adenocarcinomas [9 in situ and 13 invasive tumors]) were diagnosed. Invasive tumors were significantly larger (p 0.006), sessile or flat (p 0.004) and with lateral extension (p 0.003). Regarding non-invasive (n 470) polyps, 444 (95%) polyps were treated endoscopically (77.8% en bloc / 22.2% piecemeal) and 26 (5.5%) polyps were surgically resected (15 [57.7%] after a first endoscopic resection, in all cases fragmented). Compared to endoscopicallytreated polyps, surgically-treated polyps were significantly larger, more frequently with sessile or flat morphology, and with lateral extension, and in the same way, compared to en bloc resected polyps, in fragments-resected polyps were also significantly larger, sessile or flat and with lateral extension (p 0.001,for all). A surveillance colonoscopy was performed (median time: 5.4 months) in 154 (34.6%) of the endoscopically resected polyps. Surveillance was performed more significantly in those polyps larger, resected in fragments, with sessile or flat morphology and with lateral extension (p 0.001, for all).Residual/ recurrent neoplastic tissue was identified in 30 (6.8%) of the EMR polyps at the polypectomy site, and specifically in 22 (31%) out of the 71 piecemeal resected polyps. Conclusions: Most large polyps can be successfully eradicated endoscopically. A relatively high rate of residual/recurrent neoplasia, specifically in piecemeal-resected polyps, confirms the importance of follow-up colonoscopy.