(18)F-FDG and (68)Ga-somatostatin analogs PET/CT in patients with Merkel cell carcinoma: a comparison study

S. Taralli, M. Sollini, M. Milella, G. Perotti, A. Filice, M. Menga, A. Versari, V. Rufini

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin tumor. Currently, (18)F-fluoro-deoxy-glucose ((18)F-FDG) PET/CT is the functional imaging modality of choice. Few data are available on the use of (68)Ga-somatostatin analogs. The aim of our study was to evaluate and compare the diagnostic performance of (18)F-FDG and (68)Ga-somatostatin analog PET/CT in MCC patients. RESULTS: Fifteen patients (12 males, 3 females; median age 73 years; range 41-81 years) with histologically proven MCC (4 with unknown primary lesion) who underwent both (18)F-FDG and (68)Ga-somatostatin analog PET/CT for staging, re-staging, or treatment response assessment were retrospectively evaluated. Results of both studies were qualitatively analyzed and compared on a patient- and lesion-based analysis, using histology or clinical/radiological follow-up as reference standard for final diagnosis. According to final diagnosis, 8/15 patients had at least one MCC lesion and 7/15 had no evidence of disease. On a patient-based analysis, (18)F-FDG and (68)Ga-somatostatin analogs correctly classified as positive 8/8 (100% sensitivity) patients and as negative 6/7 (85.7% specificity) and 5/7 (71.4% specificity) patients, respectively, with no significant difference. On a lesion-based analysis, (18)F-FDG detected 67/75 lesions (89%) and (68)Ga-somatostatin analogs 69/75 (92%), with no significant difference. In four patients with unknown primary MCC, both tracers failed to identify the primary MCC site. CONCLUSIONS: Our preliminary data suggest that (18)F-FDG and (68)Ga-somatostatin analog PET/CT provide good and equivalent diagnostic performance, adding interesting insights into the complex MCC biology. However, these results do not suggest that (18)F-FDG PET/CT should be replaced by (68)Ga-somatostatin receptor imaging, which should be performed in addition, according to clinical indication, to the perspective of "personalized medicine."
Original languageEnglish
Pages (from-to)64
JournalEJNMMI Research
Issue number1
Publication statusPublished - Jul 21 2018


  • 18F-FDG
  • 68Ga-somatostatin analogs
  • Merkel cell carcinoma
  • Positron emission tomography/computed tomography


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