A comparison of 68Ga-DOTATATE and 18F-FDG PET/CT in pulmonary neuroendocrine tumors.

UNLABELLED

Our purpose was to compare the performance of (68)Ga-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-d-Phe(1),Tyr(3)-octreotate (DOTATATE), a novel selective somatostatin receptor 2 PET ligand, and (18)F-FDG in the detection of pulmonary neuroendocrine tumors using PET/CT, with correlation of uptake and tumor grade on histology.

METHODS

The imaging findings of the first 18 consecutive patients (8 men and 10 women) with pulmonary neuroendocrine tumors (11 typical carcinoids, 2 atypical carcinoids, 1 large cell neuroendocrine tumor, 1 small cell neuroendocrine carcinoma, 1 non-small cell lung cancer with neuroendocrine differentiation, and 2 cases of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia) who underwent (68)Ga-DOTATATE and (18)F-FDG PET/CT were reviewed. In all cases, the diagnosis was established on histology.

RESULTS

Of 18 patients, 15 had primary tumors (median size, 2.7 cm; range, 0.5-8 cm) and 3 had recurrent tumors. All typical carcinoids showed high uptake of (68)Ga-DOTATATE (maximum standardized uptake value [SUV(max)] >or= 8.2), but 4 of 11 showed negative or minimal (18)F-FDG uptake (SUV(max) = 1.7-2.9). All tumors of higher grade showed high uptake of (18)F-FDG (SUV(max) >or= 11.7), but 3 of 5 showed only minimal accumulation of (68)Ga-DOTATATE (SUV(max) = 2.2-2.8). Neither case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia showed uptake of (68)Ga-DOTATATE or (18)F-FDG. Typical carcinoids showed significantly higher uptake of (68)Ga-DOTATATE and significantly less uptake of (18)F-FDG than did tumors of higher grade (P = 0.002 and 0.005). There was no instance of false-positive uptake of (68)Ga-DOTATATE, but there were 3 sites of (18)F-FDG uptake secondary to inflammation. (68)Ga-DOTATATE was superior to (18)F-FDG in discriminating endobronchial tumor from distal collapsed lung (P = 0.02).

CONCLUSION

Typical bronchial carcinoids showed higher and more selective uptake of (68)Ga-DOTATATE than of (18)F-FDG. Atypical carcinoids and higher grades had less (68)Ga-DOTATATE avidity but were (18)F-FDG-avid.