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.

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.