Metabolic Syndrome Is Associated with Impaired Survival after Surgery for Pancreatic Neuroendocrine Tumors

Introduction: Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group of neoplasms. Surgery is the only curative treatment option. However, our understanding of predictors of survival after surgery remains incomplete. The aim of the study was to evaluate metabolic syndrome (MetS) as a prognostic factor in pNET. Methods: In a retrospective single-center cohort study, we examined the influence of MetS in 120 patients with curative intended resection of pNETs on overall survival (OS), recurrence-free survival, and outcome after recurrence. Results: MetS was present in 32 patients (26.6%). Patients with MetS had an impaired OS after curative intended surgery compared to patients without MetS (median OS 72 months [95% CI 13.3–130.7] vs. not reached, p < 0.001). The shortest survival was observed in patients with MetS in the presence of oligometastatic disease at time of surgery. In a multivariable Cox regression analysis, MetS was identified as an independent risk factor for mortality (hazard ratio [HR] = 4.54, 95% CI [1.88–11.00], p = 0.01). In our dataset, MetS was not associated with tumor recurrence or recurrence-free survival. Nevertheless, in patients with recurrence, MetS was associated with shorter time to recurrence (median 3.4 months, 95% CI [2.48–4.24], vs. 20.1 months, 95% CI [10.8–29.49], p < 0.001), and poor outcome (HR = 5.03, 95% CI [1.25–20.20], p = 0.01). Conclusions: We identified MetS as a negative prognostic factor after curative intended surgery for pNET. In particular, patients with oligometastatic disease might not benefit from extensive surgery in the presence of MetS. Furthermore, MetS had a strong impact on survival after recurrence.