Management and outcomes of intraductal papillary mucinous neoplasms.

Background: This study evaluated the outcome and survival of patients with radiologically suspected intraductal papillary mucinous neoplasms (IPMNs).

Methods: IPMN management was reviewed according to Fukuoka risk factors and IPMN localization, differentiating main-duct (MD), mixed-type (MT) and branch-duct (BD) IPMNs. Perioperative results were compared with those of patients undergoing resection of pancreatic ductal adenocarcinoma (PDAC) over the same interval (2010-2014). Overall (OS) and disease-specific (DSS) survival rates were calculated and subgroups compared.

Results: Of 142 patients with IPMNs, 26 had MD-IPMN, eight had MT-IPMN and 108 had BD-IPMN. Some 74 per cent of patients with MD- and MT-IPMN were managed by primary resection, whereas this was used in only 27·8 per cent of those with BD-IPMN. The risk of secondary resection and malignant transformation for BD-IPMNs smaller than 20 mm was 8 and 2 per cent respectively during follow-up. Pancreatic head resection of IPMNs was associated with an increased risk of postoperative pancreatic fistula grade B/C compared with resection of PDAC (12 of 33 (36 per cent) versus 41 of 221 (18·6 per cent) respectively; P = 0·010), and greater morbidity and mortality (Clavien-Dindo grade III: 15 of 33 (45 per cent) versus 56 of 221 (25·3 per cent) respectively; grade IV: 1 (3 per cent) versus 7 (3·2 per cent); grade V: 2 (6 per cent) versus 2 (0·9 per cent); P = 0·008). Five-year OS and DSS rates in patients with MD-IPMN were worse than those for MT- and BD-IPMN (OS: 44, 86 and 97·4 per cent respectively, P < 0·001; DSS: 60, 100 and 98·6 per cent; P < 0·001). Patients with invasive IPMN had worse OS and DSS rates than those with non-invasive dysplasia (OS: IPMN-carcinoma (10 patients) 33 per cent, high-grade dysplasia 100 per cent, intermediate-grade dysplasia 63 per cent, low grade-dysplasia 100 per cent, P < 0·001; DSS: IPMN-carcinoma 43 per cent, all grades of dysplasia 100 per cent, P < 0·001). Patients with high-risk stigmata had poorer survival than those without risk factors (OS: high-risk stigmata (35 patients) 55 per cent, worrisome features (31) 95 per cent, no risk factors (76) 100 per cent, P < 0·001; DSS: 71, 100 and 100 per cent respectively, P < 0·001).

Conclusion: The risk of malignant transformation was very low for BD-IPMNs, but the development of high-risk stigmata was associated with disease-specific mortality. Patients with IPMN had greater morbidity after resection than those having resection of PDAC.