Intensive Endoscopic Resection for Downstaging of Superficial Non‐ampullary Duodenal Epithelial Tumor Burden in Familial Adenomatous Polyposis: A Single‐center Retrospective Study on Long‐term Clinical Outcome

ABSTRACT Background and Study Aims Familial adenomatous polyposis (FAP) is a genetic condition that increases the risk of developing colorectal polyposis and cancer, as well as superficial non‐ampullary duodenal epithelial tumors (SNADETs). In this single‐center retrospective study, we investigated the long‐term clinical outcomes of intensive endoscopic resection for downstaging the SNADET burden (intensive downstaging polypectomies [IDPs]) in individuals with FAP. Methods Of 56 patients with FAP who underwent endoscopic treatment of SNADETs, 34 underwent IDPs, and 22 underwent conventional treatments, with a median follow‐up period of 71 months. IDP was defined as the resection of ≥ 3 lesions in one treatment. Results The total number of resected lesions was 495 lesions (9.7 ± 7.5 lesions/treatment [average ± standard deviation]) in the IDP group and 42 (1.4 ± 0.5 lesions/treatment) in the conventional group. No delayed bleeding was observed in the IDP group and one in the conventional group. No perforation was observed in our study. The 5‐year incidence rates of high‐grade dysplasia, invasive cancer, and cause‐specific duodenectomy in the IDP group were 15.6%, 3.6%, and 0%, respectively. Downstaging of the Spigelman stage (SS) was achieved in 50% (17/34) of patients in the IDP group. Conclusions This study demonstrated that IDP was safe and effective in downstaging the burden of SNADETs, and no duodenectomy due to SNADETs was required during the available follow‐up period in individuals with FAP, even at SS IV. Trial Registration N/A.