Optimal Surveillance of Intraductal Papillary Mucinous Neoplasms of the Pancreas Focusing on Remnant Pancreas Recurrence After Surgical Resection

Abstract

Background: The international consensus guidelines for intraductal papillary mucinous neoplasm of the pancreas (IPMN) presented clinical features as indications for surgery. Whereas surveillance for recurrence including de novo lesions is essential, optimal surveillance protocols have not been established.Aim and Methods: The aim of this study was to assess the clinical features of recurrence at the remnant pancreas (Rem-Panc) and extra-pancreas (Ex-Panc) after surgery for IPMN. Ninety-one cases of IPMN that underwent detailed preoperative assessment and pancreatectomy were retrospectively analyzed, focusing especially on the type of recurrence.Results: The IPMNs were finally diagnosed as low-grade dysplasia (LDA, n=42), high-grade dysplasia (HAD, n=19), and invasive carcinoma (IPMC, n=30). Recurrence was observed in 26 cases (28%), of which recurrence was seen at Rem-Panc in 19 cases and at Ex-Panc in 7 cases. The frequency of Rem-Panc recurrence was 10% in LDA, 21% in HDA, and 37% in IPMC. On the other hand, Ex-Panc recurrence was observed only in IPMC (23%). Ex-Panc recurrence showed shorter median recurrence-free survival (RFS) and overall survival (OS) than Rem-Panc recurrence (median RFS 8 months vs 35 months, p<0.001; median OS 25 months vs 72 months, p<0.001). Regarding treatment for Rem-Panc recurrence, repeat pancreatectomy resulted in better OS than no-pancreatectomy (MST 36 months vs 15.5 months, p=0.03). On multivariate analysis, main duct stenosis or disruption as a preoperative feature (hazard ratio [HR] 10.6, p=0.002) and positive surgical margin (HR 4.4, p=0.018) were identified as risk factors for Rem-Panc recurrence.Conclusions: The risk factors for Rem-Panc and Ex-Panc recurrence differ. Optimal surveillance based on these features is desirable to ensure that repeat pancreatectomy for Rem-Panc recurrence can be an appropriate surgical intervention.