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 during screening/baseline EGD
* Suspicion of malignancy by abdominal or endoscopic ultrasound imaging based on malignant lymph nodes, invasion of lesion beyond mucosa.
* EMR or polypectomy \< 6 weeks prior to baseline treatment.
* Untreated invasive esophageal malignancy, including margin-positive EMR.
* Active duodenitis in treatment zone during screening/baseline EGD.
* Severe medical comorbidities precluding endoscopy, or limiting life expectancy to less than 2 years in the judgment of the endoscopist.
* Uncontrolled coagulopathy or inability to be off anticoagulation or anti-platelet medication per standards of the institutions performing cryoablation.
* Known portal hypertension, visible esophageal, gastric, or duodenal varices, or history of varices.
* General poor health, multiple co-morbidities placing the patient at risk, or otherwise unsuitable for trial participation.
* Pregnant or planning to become pregnant during period of study participation.
* Patient refuses or is unable to provide written informed consent.
