Macrovascular venous invasion of pancreatic neuroendocrine tumours: impact on surgical outcomes and survival.

Background: This study evaluates the impact of macrovascular venous invasion (MVI) on surgical and survival outcomes of pancreatic neuroendocrine tumours (PNETs).

Methods: We retrospectively reviewed data of 125 patients operated for PNETs. Operative, pathological,and survival outcomes were compared between PNETs with and without MVI.

Results: Macrovascular venous invasion was detected in 25 of 125 PNETs (20%) presenting as tumour thrombi (n = 12) or venous wall invasion (n = 13). MVI was associated with larger tumours, a higher rate of lymph node involvement, less differentiated tumours, and a higher rate of perineural invasion. Resection of PNETS with MVI more often necessitated combined hepatic, venous and multivisceral resections, had a higher rate of intraoperative blood transfusion (p = 0.04) but similar morbidity (44% vs. 42%) and mortality (0 vs. 1%) as PNETs without MVI. PNETs with MVI had a lower median overall survival rate (60 vs. 149 months; p = 0.03). Multivariate analysis revealed that PNETs of the pancreatic head, synchronous liver metastases and higher tumour grade were prognostic factors for overall survival.

Conclusions: MVI is found in more advanced PNETs. Resection of PNETs with MVI is characterized by increased transfusion rate and reduced overall survival.