LAUSR

BACKGROUND AND STUDY AIMS Patients with familial adenomatous polyposis (FAP) risk developing multiple duodenal adenomas (MDAs), leading to duodenal cancer and death. We investigated the safety and efficacy of intensive endoscopic intervention for MDAs integrated with new-generation procedures. PATIENT AND METHODS This prospective phase II study, conducted at a tertiary cancer center, enrolled FAP patients with MDAs. We performed intensive endoscopic interventions, including cold snare/forceps polypectomy (CSP/CFP) and underwater endoscopic mucosal resection (UEMR). The primary endpoint was the downstaging of Spigelman stage at 1-year follow-up. RESULTS Totally, 2424 duodenal polyps in 58 patients with FAP underwent interventions, including 2413 CSPs in 57, seven CFPs in one, and four UEMRs in four patients. The major adverse event observed was one grade 3 hyperamylasemia without clinical manifestations. We performed additional UEMR, CSP, and CFP for one, eight, and 21 patients, respectively, during follow-up. Fifty-five patients completed protocol examination; the Spigelman stage was significantly reduced at the 1-year follow-up endoscopy (p<0.001), with downstaging observed in 39 patients (71%). Among the 26 patients with Spigelman stage IV at the initial examination, 23 (88%) showed downstaging. There was no major change in Spigelman stages with a median (range) of 37 (3-56) months' observation after 1-year follow-up esophagogastroduodenoscopy. CONCLUSIONS Intensive endoscopic intervention, including new-generation procedures, showed significant downstaging with acceptable adverse events for MDA in FAP patients, even those with advanced-stage disease. Lesion selection for different resection techniques may be important for suitable and sustainable management of MDA in FAP patients (Trial Reg Num: UMIN000022525).