Capsule endoscopy to detect primary tumour site in metastatic neuroendocrine tumours

Background: In patients with metastatic neuroendocrine tumours, primary tumour localisation is often difficult with morphological and/or functional imaging. Although utilised in investigating various small bowel pathologies, evidence for using video capsule endoscopy to identify suspected small bowel primaries in patients exhibiting metastatic neuroendocrine tumours is limited. Aims: To assess the role of video capsule endoscopy in locating primary small bowel neuroendocrine tumours when conventional imaging fails to identify the origin of metastatic disease. Methods: We retrospectively compared our institutional database of patients presenting with metastatic neuroendocrine tumours between January 2010 and December 2013 with an analogous database of patients undergoing video capsule endoscopy for various indications. Patients whose primary tumours were not located radiologically and also underwent capsule endoscopy were identified. Results: 390 patients with metastasised neuroendocrine tumours presented within the study period. In 11 (2.8%) the primary tumour was not located radiologically. Video capsule endoscopy identified lesions suggestive of small bowel primary in 8/10 patients in whom it was successful. Small bowel primary was confirmed by histological analysis of surgical specimens. Conclusions: Our study supports the use of video capsule endoscopy as part of the diagnostic work-up in selected patients presenting with metastatic neuroendocrine tumours of unknown primary. The clinical utility of this technology requires clearer definition.