Radioguided Surgery for Gastroenteropancreatic Neuroendocrine Tumours; a Systematic Literature Review

Abstract Background:Radioguided surgery (RGS) for gastroenteropancreatic neuroendocrine tumours (GEP-NETs) has been suggested as a way to improve intraoperative lesion detection. This systematic literature review of reports of the use of RGS for GEP-NETs was performed to determine if there is a benefit.Methods: A literature search was conducted using Google Scholar and PubMed, and snowballing from any relevant literature. Full-text studies were included if they were published in the English Language and reported outcomes of RGS on human subjects with GEP-NETs. Qualitative data synthesis was performed. Results: 26 papers including a total of 209 patients were included. The tracers used were predominantly indium-111 pentetreotide, gallium-68 DOTA-Peptides, and technetium-99m EDDA/HYNIC-Peptides. Heterogeneous protocols make comparisons difficult, but most papers reported a benefit from the use of RGS in tumours in the gastrointestinal tract; utility in localisation of pancreatic tumours was less clear. Time between tracer administration and operation varied; from 16 hours to 8 days with indium-111, 0-24 hours with technetium-99m and 19-193 minutes with gallium-68. Eight teams reported the thresholding technique used for discrimination – four used a ratio, four statistical methods, and one looked at the sensitivity and specificity of different cut-offs. Six teams performed follow-up of 24 patients (three pancreas, eight gastrinoma, 13 gastrointestinal tract) for between 3 months and 3 years. Two patients relapsed (one pancreas, one gastrinoma) between six and 12 months post-surgery. Conclusions:RGS appears to aid in localisation of gastrointestinal NETs, but the benefit is more equivocal in pancreatic NETs. Further work into outcomes is warranted.