The role of somatostatin receptor scintigraphy in the diagnosis and follow-up of the pancreatic neuroendocrine neoplasms

The aim of investigation was to assess the role of somatostatin receptor scintigraphy in diagnosis and follow-up of pancreatic neuroendocrine neoplasms. Somatostatin receptor scintigraphy was performed with 740 MBq 99mTc-EDDA/HYNIC TOC for diagnosis of primary tumors and follow-up after the therapy. There were 63 true positive, 24 true negative, 4 false positive, and 6 false negative findings. Sensitivity was 91.3 %, specificity 85.7 %, positive predictive value 94.0 %, negative predictive value 80.0 %, accuracy 89.7 %. The SPECT contributed diagnosis in 28 true positive findings. In 32 patients (33 %) somatostatin receptor scintigraphy significantly changed the management of the patients (10 had surgery, in 17 somatostatin analogues, and in 5 peptide receptor radionuclide therapy was introduced). Mean Ki-67 index in true positive patients was 13.8 ±5.0 % while in true negative 7.1 ± 3.4% which is significantly lower at p < 0.05. There was significantly (p < 0.01) higher number of increased chromogranin A values in true positive than in true negative patients (p = 0.000857). Our results confirmed the value of SRS in the diagnosis and follow-up of the patients with pancreatic neuroendocrine neoplasms PanNEN if primary tumors, recurrences or metastases are suspected, as well as for appropriate choice of the therapy.