68Ga-DOTANOC PET/CT accuracy for neuroendocrine (NET) lesions detection: The Bologna experience

Objectives To evaluate the accuracy of 68Ga-DOTANOC PET/CT in patients with known or suspected NET.

Methods We included the patients with known or suspected NET referred to us by the Internal Medicine Unit. All patients (204) underwent 68Ga-DOTANOC PET/CT at our centre and completed an extensive clinical and imaging follow-up of at least 12 months. Indications to perform PET included staging (18), re-staging after surgery or therapy (39), interim PET (16), follow-up (78), equivocal CI (27) or markers (3), UPC (13), suspected NET in unexplained diarrhea (7) or suspected insulinoma (1) and screening in MEN (2). Clinical and imaging follow-up was used as standard of reference to finally describe PET results as true positive, true negative, false positive and false negative.

Results We evaluated 204 patients with known (188) or suspected (16: 7 unexplained diarrhea, 7 suspected NET lesions on conventional imaging, 2 screening in MEN) NET lesions. In 126 cases the primary was excised before PET/CT. The most frequent primary site was the GI tract (137/204) followed by lungs (38), ear (6), ovary (1) and kidney (1). In 21 cases the primary was not identified: 5 unknown primary in patients with NET metastasis, 16 suspected NET lesions on CT (not confirmed on neither PET nor pathology). At the time of the PET scan, 89 patients were receiving therapy (SST, PRRT, chemotherapy, alone or in combination) while 115 were untreated. Overall and site by site PET sensitivity, specificity, positive (PPV) and negative (NPV) predictive values are reported in table 1. ""

Conclusions 68Ga-DOTANOC PET/CT was accurate for the detection of NET lesions, particularly at bone, lung and lymphnodes level

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