Comparison of gallium-68 somatostatin receptor and 18F-fluorodeoxyglucose positron emission tomography in the diagnosis of neuroendocrine tumours: A systematic review and meta-analysis.

Abstract

A meta-analysis was performed to compare the diagnostic performance of gallium-68 (18Ga) somatostatin receptor positron emission tomography (68Ga-SSTR PET) and fluorine-18-fluorodeoxyglucose (18F-FDG) PET in patients with neuroendocrine tumours (NET) and whether the two imaging modalities can be mutually substituted in clinical work. We performed electronic literature searches of the MEDLINE, PubMed, Embase and Cochrane Library databases for English-language articles from the earliest available date of indexing through 30 July 2019. We calculated the pooled sensitivity, specificity and diagnostic odds ratios (DOR) with 95% confidence intervals (95% CI) of 68Ga-SSTR PET and 18F-FDG PET in NET. We drew a summary receiver operator characteristic (SROC) curve and calculated the area under the curve (AUC) to measure the accuracy of 68Ga-SSTR PET and 18F-FDG PET in patients or lesions with NET. Thirty studies comprising 3401 patients and 5793 lesions with NET were included in this meta-analysis. The pooled sensitivity, sensitivity, DOR and AUC for 68Ga-SSTR PET or PET/computed tomography (CT) in the diagnosis of NET, based on lesion patient, were 0.92(0.89-0.95), 0.91(0.83-0.95),119(51-282) and 0.96(0.94-0.98), and based on lesion, were 0.95(0.86-0.98), 0.93(0.83-0.97), 229(43-1205) and 0.98(0.96-0.99), respectively. The pooled sensitivity, sensitivity, DOR and AUC for 18F-FDG PET or PET/CT in NET were 0.70(0.41-0.89), 0.97(0.70-1.00), 67(7-612) and 0.94(0.92-0.96), respectively, when analyzed on a per-patient basis.The pooled sensitivities of 68Ga-SSTR PET/CT were 0.923 (95% CI: 0.884-0.952), 0.902 (0.862-0.934) and 0.578 (0.482-0.669) in the G1(ki67,≤2%), G2(ki67,>3%,≤20% and G3(ki67,>20%) groups based on patients with NET, respectively. The pooled sensitivities of 18F-FDG PET/CT were 0.378 (0.319-0.440), 0.554 (0.492-0.615) and 0.712 (0.633-0.783) in the G1, G2 and G3 groups based on patients with NET, respectively. The 68Ga-SSTR PET has highly sensitive and had a greater diagnostic value than 18F-FDG PET for patients with NET. Fluorine-18-FDG PET, however, had significant specificity than 68Ga-SSTR PET. The 68Ga-SSTR has high sensitivity in G1/G2 NET, while 18F-FDG has a low positive rate. In G3 NET, however, the opposite is true. Therefore, the 68Ga-SSTR PET and 18F-FDG PET modalities are complementary rather than substitutive in clinical practice.