Reasons for surveillance dropout.

This study aimed to evaluate how hospital distance and changes in surveillance hospitals influence adherence to surveillance, the cumulative risk of familial adenomatous polyposis-related tumors, and survival outcomes in patients with familial adenomatous polyposis. We conducted a multicenter retrospective study in a specific region of Japan and analyzed 79 patients with familial adenomatous polyposis who underwent total colectomy or proctocolectomy between 1987 and 2025 across 9 accredited hospitals. We examined the associations between straight-line distance to the hospital, changes in surveillance centers, and surveillance adherence, as well as the cumulative risk of familial adenomatous polyposis-related tumors and survival outcomes. The 10-year surveillance adherence rate was 86.5%. During follow-up, 31.6% of patients changed hospitals. Hospital distance did not differ significantly between those who maintained or dropped out of surveillance. However, patients residing ≥40 km from their hospital were significantly more likely to switch hospitals (61.5% vs. 13.2%, p