A Real-world Multicenter Prospective Study of Everolimus in Pancreatic Neuroendocrine Tumors: The ‘PROTOR’ Study

Background/Aim: Pancreatic neuroendocrine tumors (panNETs) are rare neoplasms with challenging disease management. We aimed to evaluate the progression-free survival (PFS) and overall response rate (ORR) in chemotherapy-naïve patients with unresectable or metastatic Grade (G) 1-2 panNETs treated with everolimus in the routine care in Greece. Patients and Methods: This was a multicenter, prospective, observational study. Eligible patients were recently (≤4 weeks) initiated on treatment with everolimus and were followed for up to 48 months. Results: Nineteen eligible patients (mean age 55.1 years) were enrolled. All patients had metastatic disease and 84.2% had G2 panNET. Everolimus was initiated in combination with somatostatin analogues in 84.2% of the patients. The mean everolimus treatment duration was 21.5 months. The median Kaplan-Meier-estimated PFS was 20.4 months (95% confidence interval=14.1-41.5). The ORR was 27.8%. The rate of everolimus-related adverse events was 84.2% (Grade ≥3: 31.6%). Conclusion: Everolimus displayed clinical benefit and a predictable safety profile in pancreatic neuroendocrine tumors.