The long term risk of malignancy in patients with branch duct intraductal papillary mucinous neoplasms of the pancreas.

UNLABELLED: In patients (pts) with branch duct intraductal papillary mucinous neoplasms of the pancreas (BD-IPMN), the risk of malignant progression is well described at short- and mid-term. Few data beyond 5 years are available.

PATIENTS AND METHODS: Prospective study in consecutive patients (pts) with BD-IPMN and follow-up (F/U) ≥60 months to assess long term risk of malignant progression. All computed tomographies and magnetic resonance cholangiopancreatographies performed every 1 or 2 years (depending on the maximum size of cyst) were read by the same radiologist. EUS was performed in case of occurrence of main pancreatic duct (MPD) dilation or mural nodule >5 mm. Size increase was considered significant if >5 mm. Size variation, criteria suggestive of malignancy, operative therapy and pathology were recorded.

RESULTS: 53 pts were included (median age at diagnosis: 61 years, median F/U: 84 months (range: 60-132) including 5 F/U >120 months). Lesions were stable in 38 pts (72%). Size increased in 8 pts (15%) (median increase : 11 (5-33) mm) without mural nodule (MN). One of those was operated on (low-grade dysplasia). A MN appeared in 5 pts (9%). ≥5 mm in 2 pts (5 and 15 mm) who were operated on (intermediate-grade dysplasia in both). The 3 remaining pts (MN < 5 mm) were carefully followed-up. Invasive advanced carcinoma occurred in 2 pts, both after 84 months F/U. In one of these, no imaging changes were noted 12 months before diagnosis of malignancy.

CONCLUSION: In BD-IPMN, the risk of malignant evolution persists after 60 months F/U including invasive carcinomas. F/U imaging surveillance is still necessary beyond this delay in patients fit for potential surgery.