Detection rate of somatostatin receptor PET in patients with recurrent medullary thyroid carcinoma: a systematic review and a meta-analysis.

PURPOSE: Several articles have demonstrated the high diagnostic performance of somatostatin receptor positron emission tomography (PET) in patients with neuroendocrine tumours (NETs). On the other hand, only a few studies have evaluated the detection rate (DR) of this imaging method in recurrent medullary thyroid carcinoma (MTC). We aimed to perform a systematic review and a meta-analysis of the DR of somatostatin receptor PET or PET/CT in patients with recurrent MTC to add evidence-based data to this setting. METHODS: A comprehensive computer literature search of studies published in PubMed/MEDLINE and the Cochrane Library Database through May 2017 and regarding somatostatin receptor PET or PET/CT in patients with recurrent MTC was carried out. DR was determined on a per patient-basis. A sub-analysis considering serum calcitonin (Ctn) values was also performed. RESULTS: Nine studies on the diagnostic performance of somatostatin receptor PET or PET/CT in detecting recurrent MTC were discussed in the systematic review. The meta-analysis of these selected studies provided the following DR on a per patient-based analysis: 63.5% [95% confidence interval (95%CI): 49-77]. Heterogeneity among the selected studies was found. DR of somatostatin receptor PET or PET/CT increased in patients with higher serum Ctn levels (83% for Ctn >500 ng/L). CONCLUSIONS: In patients with recurrent MTC, somatostatin receptor PET or PET/CT demonstrated a non-optimal DR which increased in patients with higher serum Ctn values. The diagnostic performance of somatostatin receptor PET or PET/CT in recurrent MTC is lower compared to that of the same imaging method in the majority of NETs.