Investigation of the Optimal Duration and Modality for Postoperative Surveillance of Intraductal Papillary Mucinous Neoplasm (IPMN): A Single-Center Retrospective Study

<b>Background/Objectives</b>: Although multiple guidelines exist for the management of intraductal papillary mucinous neoplasms (IPMN), the duration and modality of postoperative surveillance remain inconsistent. We aimed to retrospectively review medical images of patients with IPMN after surgery and to investigate the optimal surveillance duration and modality. <b>Methods</b>: In this study, we included 191 patients with IPMN who underwent surgery at a single institution between January 2006 and May 2024. Patients were followed from the postoperative period until July 2025. Image interpretation reports written by diagnostic radiologists were examined to determine the time to recurrence detection and the imaging modality used. <b>Results</b>: Sixteen patients (8.3%) were eligible during the observation period. Seven patients experienced intrapancreatic recurrence, and ten patients experienced extrapancreatic recurrence (one patient was included in both categories). The mean time to identification of intrapancreatic lesions was 63.9 months; five of seven cases were detected using contrast-enhanced computed tomography (CT). The mean time to identification of extrapancreatic lesions was 12.0 months, which was significantly shorter than that for intrapancreatic lesions (<i>p</i> = 0.005). Eight of ten extrapancreatic recurrences were detected using contrast-enhanced CT. <b>Conclusions</b>: Extrapancreatic lesions appeared earlier after IPMN surgery than intrapancreatic lesions. Contrast-enhanced CT was the most commonly used modality for detecting recurrent lesions, suggesting its usefulness in postoperative surveillance.