Seventeen studies (n=7,464 participants) were included in the review. The number of participants diagnosed with neuroendocrine tumours ranged from 11 to 92 per study. The overall quality scores of included studies ranged from 2 to 4 points, with most studies (nine) scoring 2 points. Most studies (15) were retrospective, and most (13) did not use the specified method to determine final diagnosis.
The diagnostic yields for all midgut neuroendocrine tumours were: 78.9% (range 20 to 100; three studies) for angiography; 56% (range 0 to 100; five studies) for endoscopy; 86.6% (range 0 to 100; seven studies) for CT; 60% (one study) for video-capsule enteroscopy; 90.5% (range 65 to 100;: three studies) for OctreoScan; 59.1% (range 43 to 66; two studies) for I131-MIBG scintigraphy; 51.6% (range 5 to 100; four studies) for contrast intestinal radiography; 17.9% (range 0 to 20; three studies) for chromogranin serum level; and 37.5% (range 0 to 100; 10 studies) for 5-HIAA urinary level.
The pooled diagnostic yields of endoscopy, intestinal contrast radiology, and video capsule endoscopy were similar. The pooled diagnostic yields of CT and angiography were also similar. The pooled diagnostic yield of OctreoScan was significantly higher than that of I131-MIBG scintigraphy (p<0.001). The pooled diagnostic yield of urine 5-HIAA level was significantly higher than that of serum chromogranin A (p=0.001). Data were also reported separately for neuroendocrine tumours of the duodenum, jejunum/ileum, and appendix.
The authors presented a diagram showing a possible algorithm for the diagnostic work-up of midgut neuroendocrine tumours.