Retrospective analysis of 68Ga-DOTA-NOC PET and CT for bone metastasis detection in neuroendocrine tumours patients

Objectives to compare the detection rate of bone lesions by ⁶⁸Ga-DOTA-NOC PET and CT in neuroendocrine tumours (NET) patients (pts).

Methods 44 pts with pathology proven NET were studied by 68Ga-DOTA-NOC PET for staging (7), unknown primary tumour detection (3), re-staging (9), re-staging before radio-immunotherapy (1), PET during therapy (6), equivocal conventional imaging at sites other than bone (7) and follow-up (11).Criteria for inclusion were having a PET positive for at least one bone lesion. PET images were retrospectively reviewed by two experienced nuclear medicine specialists unaware of the pts medical history. PET results were compared with the corresponding CT images reviewed by two experienced radiologists. Imaging data were compared with follow up.

Results Of the 44 PET-positive cases, CT detected at least one bone lesion in 35/44 and was negative in 9. Bone metastasis identified by PET in CT-negative cases were located in the temporal bone (3 lesions, 2/3 identified by PET at the periphery of the surgical area), vertebrae (4), ilium (3), ribs (1) and humerus (1).Among PET and CT positive pts (35), PET detected a higher number of lesions in 20/35, a lower number in 8 while in 7 pts PET and CT were concordant.In 9 CT-negative pts, PET influenced the clinical management addressing the pts to further therapy.

Conclusions ⁶⁸Ga-DOTA-NOC PET was more sensitive to identify bone metastasis and changed the clinical management in 9/44 pts.