Location Matters in IPMN: Clinicopathological differences, malignancy risk and oncological outcomes for lesions located in head vs body and tail of the pancreas

Abstract

Background

The clinico-pathological characteristics and accuracy of the current International Association of Pancreatology guidelines for IPMN in relation to its location within the pancreas has not been investigated.

Methods

751 patients who underwent pancreatic resection for IPMN in two tertiary referral centers were retrospectively categorized into subgroups according to location within the pancreas. Likelihood of worrisome features, high-risk stigmata (HRS), clinico-pathological features and presence of malignancy were compared.

Results

480 (64%) patients had IPMN in the ventral pancreas (i.e. head, uncinate process and neck), and 271(36%) in the dorsal gland (i.e. body/tail). Malignancy was present in 54% (n = 259) of patients with ventral IPMN and in 39% (n = 107) of those with dorsal lesions (p < 0.0001). There was a significantly higher proportion of intestinal epithelium in ventral IPMNs when compared to those in the dorsal pancreas, both in the general cohort and in invasive cancer group (27% vs 15%, OR: 1.94 95%CI:1.16-3.24 p = 0.006 and 31% vs 22% OR 1.52 95%CI: 0.77-3, p = 0.24 respectively). Patients with ventral IPMN more frequently presented with HRS (49%vs 37%, p < 0.001), while dorsal IPMN often showed only worrisome features (54%vs 43%, p = 0.06). ROC curve analysis identified optimal cut-off values for main pancreatic duct diameter of 9 mm in ventral IPMNs and 5 mm in dorsal IPMNs for malignancy prediction.

Conclusions

Ventral IPMNs are more commonly resected and show higher rates of intestinal epithelium and malignancy compared with dorsal lesions. A MPD size > 5 mm in IPMNs of the dorsal pancreas is associated with a substantial risk of malignancy.