Partial Response Upon Peptide Receptor Radionuclide Therapy in a Highly Proliferative Pancreatic Neuroendocrine Tumor.

We report on a patient diagnosed with an aggressive pancreatic neuroendocrine tumor (NET G3; Ki67 = 60%), who underwent pancreatic resection with partial removal of liver lesions. The patient refused chemotherapy. Dual-tracer imaging with 18F-FDG and somatostatin receptor (SSTR)-targeted PET/CT was conducted. Radiotracer accumulation on both imaging modalities in bilobar hepatic lesions was observed. "Cold" somatostatin analogues with four cycles of peptide receptor radionuclide therapy (PRRT) were initiated, leading to partial response. Even in highly proliferative but differentiated G3 NET (Ki67>55%), SSTR expression in sites of disease should be evaluated, which may then allow PRRT, even as first-line systemic treatment.