Theranostics 2017; 7(5):1149-1158. doi:10.7150/thno.18068

Research Paper

Dual Somatostatin Receptor/FDG PET/CT Imaging in Metastatic Neuroendocrine Tumours: Proposal for a Novel Grading Scheme with Prognostic Significance

David LH Chan, Nick Pavlakis, Geoffrey P Schembri, Elizabeth J Bernard, Edward Hsiao, Aimee Hayes, Tristan Barnes, Connie Diakos, Mustafa Khasraw, Jaswinder Samra, Enid Eslick, Paul J Roach, Alexander Engel, Stephen J Clarke, Dale L Bailey

Departments of Nuclear Medicine, Medical Oncology and Surgery, Royal North Shore Hospital, Sydney Medical School and Faculty of Health Sciences, University of Sydney, and Sydney Vital Translational Cancer Research Centre, Sydney, Australia


Background: PET scans using FDG and somatostatin receptor imaging agents have both been used to study neuroendocrine tumours. Most reports have documented the sensitivity and specificity of each radiopharmaceutical independently, and even suggested the superiority of one over the other for different grades of disease.

Aim: The aim of this work was to develop a grading scheme that describes the joint results of both the FDG and somatostatin receptor imaging PET scans in staging subjects with neuroendocrine tumours in a single combined parameter. The grading scheme that has been developed is referred to as the NETPET grade.

Methods: This is a retrospective study which assessed subjects who had both FDG and somatostatin receptor PET imaging at our institution within 31 days of each other. The NETPET grade was assigned by experienced nuclear medicine physicians and compared with other clinical data such as WHO grade and overall survival.

Results: In the period 2011-2015 we were able to recruit 62 subjects with histologically proven metastatic neuroendocrine tumour for review. The NETPET grade incorporating both the FDG and somatostatin receptor imaging results was significantly correlated with overall survival by univariate analysis (p=0.0018), whereas in this cohort the WHO grade at the time of diagnosis did not correlate with survival.

Conclusions: The NETPET grade has promise as a prognostic imaging biomarker in neuroendocrine tumours. It permits the capturing of the complexity of dual radiotracer imaging in a single parameter which describes the subjects' disease and is readily amenable to use in patient management and further research.

Keywords: PET scans, Neuroendocrine tumour

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How to cite this article:
Chan DL, Pavlakis N, Schembri GP, Bernard EJ, Hsiao E, Hayes A, Barnes T, Diakos C, Khasraw M, Samra J, Eslick E, Roach PJ, Engel A, Clarke SJ, Bailey DL. Dual Somatostatin Receptor/FDG PET/CT Imaging in Metastatic Neuroendocrine Tumours: Proposal for a Novel Grading Scheme with Prognostic Significance. Theranostics 2017; 7(5):1149-1158. doi:10.7150/thno.18068. Available from