Diagnostic Performance of Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography in Patients with Merkel Cell Carcinoma: A Systematic Review and Meta-Analysis

Background Some studies reported the usefulness of fluorine-18-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography (PET) and PET/computed tomography (CT) in patients with Merkel cell carcinoma (MCC). Objective The aim of this study was to systematically review and meta-analyze published data about the diagnostic performance of 18 F-FDG PET and PET/CT in patients with MCC. Methods A comprehensive literature search of studies published through June 2013 regarding 18 F-FDG PET and PET/CT in patients with MCC was performed. All retrieved studies were reviewed and qualitatively analyzed. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR? and LR-) and diagnostic odds ratio (DOR) of 18 F-FDG PET or PET/CT in patients with MCC on a per examination-based analysis were calculated. The area under the summary receiver operating characteristic (ROC) curve was calculated to measure the accuracy of 18 F-FDG PET or PET/CT in these patients. Results Ten studies comprising 329 patients (549 scans) with MCC were included in the qualitative analysis (systematic review) and discussed. The quantitative analysis (meta-analysis) of six selected studies (including 92 patients with MCC) provided the following results on a per examination-based analysis: sensitivity was 90 % (95 % CI 80‐96), specificity 98 % (95 % CI 90‐100), LR? 12 (95 % CI 4.3‐33.0), LR- 0.15 (95 % CI 0.08‐0.28), and DOR 86.8 (95 % CI 23‐327). The area under the summary ROC curve was 0.96. No significant statistical heterogeneity between the studies was found. Conclusions In patients with MCC, 18 F-FDG PET or PET/CT demonstrated high sensitivity and specificity, being accurate methods in this setting. Nevertheless, the literature focusing on the use of PET and PET/CT in MCC still remains limited. Prospective studies are needed to substantiate the high diagnostic accuracy of these methods in MCC.