The Role of ^sup 68^Ga-DOTATATE PET in Patients with Neuroendocrine Tumors and Negative or Equivocal Findings on ^sup 111^In-DTPA-Octreotide Scintigraphy

^sup 111^In-diethylenetriaminepentaacetic acid (DTPA)-octreotide scintigraphy is currently the nuclear medicine imaging modality of choice for identifying neuroendocrine tumors. However, there are cohorts of patients in whom scintigraphy findings are negative or equivocal. We evaluated the role of ^sup 68^Ga-DOTATATE PET in a selected group of patients with negative or weakly positive findings on ^sup 111^In-DTPA-octreotide scintigraphy to determine whether ^sup 68^Ga-DOTATATE PET is able to detect additional disease and, if so, whether patient management is altered. Methods: Fifty-one patients with a histologically confirmed diagnosis of neuroendocrine tumors were included. Of the 51 patients, 35 who were negative and 16 equivocal for uptake on ^sup 111^In-DTPA-octreotide scintigraphy underwent ^sup 68^Ga-DOTATATE PET. Findings were compared using a region-by-region analysis. All findings were verified with CT or MRI. After ^sup 68^Ga-DOTATATE PET, all cases were reviewed to determine whether the ^sup 68^Ga-DOTATATE PET findings resulted in any alteration in management, in terms of suitability for peptide receptor therapy, somatostatin analogs, and surgery. Results: Of the 51 patients, 47 had evidence of disease on cross-sectional imaging or biochemically. ^sup 68^Ga-DOTATATE PET was positive in 41 of these 47 patients (87.2%). No falsepositive lesions were identified. ^sup 68^Ga-DOTATATE PET detected 168 of the 226 lesions (74.3%) that were identified with crosssectional imaging. ^sup 68^Ga-DOTATATE PET identified significantly more lesions than ^sup 111^In-DTPA-octreotide scintigraphy (P < 0.001). There was no correlation between ^sup 68^Ga-DOTATATE uptake and histologic grade of neuroendocrine tumors. ^sup 68^GaDOTATATE imaging changed management in 36 patients (70.6%), who were subsequently deemed suitable for peptide receptor-targeted therapy. Conclusion: In patients with negative or equivocal ^sup 111^In-DTPA-octreotide findings, ^sup 68^Ga-DOTATATE PET identifies additional lesions and may alter management in most cases. [PUBLICATION ABSTRACT]