Identification of patients with branch-duct intraductal papillary mucinous neoplasm and very low risk of cancer: multicentre study

Abstract

Background: Different surveillance strategies for patients with low-risk branch-duct (BD) intraductal papillary neoplasm (IPMN) have been described. The aim of this study was to describe the natural history of low-risk BD-IPMN, and to identify risk factors for the development of worrisome features (WF)/high-risk stigmata (HRS) and of pancreatic malignancies.

Methods: This was a multicentre retrospective study of patients with BD-IPMN who were under active surveillance between January 2006 and December 2015. Patients were eligible if they had a low-risk lesion and had a minimum follow-up of 24 months. Outcomes were development of WF/HRS or cytologically/histologically confirmed malignant IPMN.

Results: Of 837 patients included, 168 (20 per cent) developed WF/HRS. At the end of the observation time, 132 patients (79 per cent) with WF/HRS were still under surveillance without progression to pancreatic cancer. Factors associated with the development of WF or HRS in multivariable analysis included localized nodules (versus diffuse: hazard ratio (HR) 0.43, 95 per cent c.i. 0.26 to 0.68), cyst size 15-19 mm (versus less than 15 mm: HR 1.88, 1.23 to 2.87) or at least 20 mm (versus less than 15 mm: HR 3.25, 2.30 to 4.60), main pancreatic duct size over 3 mm (versus 3 mm or less: HR 2.17, 1.41 to 3.34), and symptoms at diagnosis (versus no symptoms: HR 2.29, 1.52 to 3.45). Surveillance in an endoscopy-oriented centre was also associated with increased detection of WF or HRS (versus radiology-oriented: HR 2.46, 1.74 to 3.47).

Conclusion: Conservative management of patients with low-risk BD-IPMN is safe and feasible.

Fig. 1

Number of examinations during follow-up until identification of worrisome features or high-risk stigmata US, ultrasonography; EUS, endoscopic ultrasonography.

Fig. 2

Development of worrisome features or high-risk stigmata during follow-up of 837 patients with branch-duct intraductal papillary mucinous neoplasms The shaded area represents the 95 per cent confidence interval.

Fig. 3

Detection of worrisome features or high-risk stigmata in endoscopy-oriented compared with radiology-oriented centres P < 0.001 (log rank test). Hazard ratio 2.46 (95 per cent c.i. 1.74 to 3.47) for endoscopy versus radiology, adjusted for site (diffuse, localized), cyst size (less than 15, 15–19, at least 20 mm), main pancreatic duct size (3 mm or less, more than 3 mm), and presence of symptoms. The shaded areas represent 95 per cent confidence intervals.

Fig. 4

Cumulative incidence of worrisome features or high-risk stigmata during surveillance in low-and high-risk groups The low-risk group includes patients with a main pancreatic duct no larger than 3 mm, cyst size less than 15 mm, and no symptoms. The shaded area represents the 95 per cent confidence interval.