CryoBalloon Ablation for Treatment of Duodenal Adenomas

Inclusion Criteria: * Sporadic duodenal adenomas between 1 to 5 cm in widest diameter * FAP patient with Spigelman class 2, 3 or 4 (see definition below) * Polyp characteristics: Non-polypoid lesions Paris 2A and 2B, or * Sessile adenomas, occupying no more than 50% circumference of duodenum, and no more than 3 duodenal folds * Individuals must be considered high risk for surgery or endoscopic resection, due to complication risk, or declined standard therapies. * Prior endoscopic mucosal resection (EMR) or saline-assisted polypectomy allowed if polyp characteristics meet inclusion criteria. Exclusion Criteria: * Suspected or proven duodenal carcinoma * Paris 1p pedunculated, Paris 2c, or 3 lesions * Paris 1s lesion \> 4 mm thick (estimated with closed biopsy forceps) * Ampullary lesion or lesion involving the ampulla * Prior failed ablative treatment with Argon Plasma Coagulation, laser, or cryotherapy * Pre-existing esophageal, gastric, pyloric, or duodenal stenosis/stricture preventing advancement of a therapeutic endoscope during screening/baseline esophagogastroduodenoscopy (EGD.) Subjects are eligible if the stenosis/stricture is dilated to at least 15mm, but baseline treatment may need to be delayed. * Any endoscopically-visualized abnormalities such as ulcers, masses or nodules during screening/baseline EGD within 3 cm of the treatment area. * Subjects with nodular polyps or suspicion of invasive cancer by white light endoscopy /enhanced imaging/biopsy identified du…