Characteristics, management, and outcomes of patients with VIPoma-A retrospective analysis of the ENETS database

VIPoma is an extremely rare functioning pancreatic neuroendocrine tumor. Therefore, data regarding treatment and outcome are very limited. Aim (s): This multicenter study aimed to analyze clinical characteristics, real-world management, and outcomes of patients with VIPoma.

Patients with VIPoma treated in a 20-year period at 14 referral centers for neuroendocrine tumors (NET) were collected in the ENETS Database. Clinical characteristics, therapeutic interventions, and outcomes were analyzed retrospectively. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method.

Of 70 patients, 59 (54% male) with a median age of 55 years were included. Forty-six (78%) patients were diagnosed due to the classical watery diarrhea-hypokalemia-achlorhydria (WDHA) syndrome, and 40 (68%) presented with distant metastases at diagnosis. Fifty-two (88%) had serum VIP levels >2 times the upper normal limit and the median Ki-67 index was 5% (range 1%-40%). Surgery of the primary VIPoma was performed in 32 (54%), with curative intent in 22 (37%). In patients with stage I-III disease (n = 19), long-term cure was achieved in only 26% (5/19), with a median DFS of 81 (95%-CI: 1-215) months and 10-year OS of 78% (95%-CI: 61%-100%). In stage IV patients (n = 53, 40 at diagnosis, 13 disease progression), the sequence and type of 354 treatment lines varied, while SSA (n = 77, 22%), loco-regional liver-directed therapy (n = 72, 20%), and chemotherapy (n = 69, 19%) were most often applied. Median OS for patients with stage IV at diagnosis was 142 (95%-CI: 87-not available (NA)) months with 10-year survival of 50% (95%-CI: 35%-73%).

Patients with VIPoma treated at NET centers have relatively favorable survival, even with distant metastases at diagnosis, although long-term cure rates remain low.