Safety and Efficacy of 68Ga-DOTATATE PET/CT for Diagnosis, Staging, and Treatment Management of Neuroendocrine Tumors

Abstract

Our purpose was to evaluate the safety and efficacy of (68)Ga-DOTATATE PET/CT compared with (111)In-pentetreotide imaging for diagnosis, staging, and restaging of pulmonary and gastroenteropancreatic neuroendocrine tumors.

Methods: (68)Ga-DOTATATE PET/CT and (111)In-pentetreotide scans were obtained for 78 of 97 consecutively enrolled patients with known or suspected pulmonary or gastroenteropancreatic neuroendocrine tumors. Safety and toxicity were measured by comparing vital signs, serum chemistry values, or acquisition-related medical complications before and after (68)Ga-DOTATATE injection. Added value was determined by changes in treatment plan when (68)Ga-DOTATATE PET/CT results were added to all prior imaging, including (111)In-pentetreotide. Interobserver reproducibility of (68)Ga-DOTATATE PET/CT scan interpretation was measured between blinded and nonblinded interpreters.

Results: (68)Ga-DOTATATE PET/CT and (111)In-pentetreotide scans were significantly different in impact on treatment (P < 0.001). (68)Ga-DOTATATE PET/CT combined with CT or liver MRI changed care in 28 of 78 (36%) patients. Interobserver agreement between blinded and nonblinded interpreters was high. No participant had a trial-related event requiring treatment. Mild, transient events were tachycardia in 1, alanine transaminase elevation in 1, and hyperglycemia in 2 participants. No clinically significant arrhythmias occurred. (68)Ga-DOTATATE PET/CT correctly identified 3 patients for peptide-receptor radiotherapy incorrectly classified by (111)In-pentetreotide.

Conclusion: (68)Ga-DOTATATE PET/CT was equivalent or superior to (111)In-pentetreotide imaging in all 78 patients. No adverse events requiring treatment were observed. (68)Ga-DOTATATE PET/CT changed treatment in 36% of participants. Given the lack of significant toxicity, lower radiation exposure, and improved accuracy compared with (111)In-pentetreotide, (68)Ga-DOTATATE imaging should be used instead of (111)In-pentetreotide imaging where available.

Keywords: 111In-pentetreotide; 68Ga-DOTATATE; carcinoid; neuroendocrine; toxicity.

Conflict of interest statement

DISCLOSURE

No other potential conflict of interest relevant to this article was reported.

© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Figures

FIGURE 1

Standards for reporting diagnostic accuracy (STARD) flow diagram of 68Ga-DOTATATE and 111In-Pentetreotide results. 68Ga-DOTATATE = 68Ga-DOTATATE PET/CT scan; 111In-pentetreotide = 111In-pentetreotide scans of all types (planar, SPECT, or SPECT/CT). *Bowel = small or large bowel; Gastric = gastric, duodenal, or pancreatic primary tumors. CUP = metastatic carcinoma with unknown primary.

FIGURE 2

Axial gadoxetate disodium (Eovist) MRI (A) and intravenous contrast-enhanced CT (B) images reveal some of the widespread metastatic disease in liver. Anterior planar 111In-pentetreotide scan (C) and SPECT/CT (not shown) demonstrate uptake only in primary ileal tumor in abdominal right lower quadrant. On the basis of these findings, patient would not be a candidate for PRRT treatment. 68Ga-DOTATATE PET/CT (only 3-dimensional anterior maximum-intensity projection shown in D) demonstrates intense uptake in primary tumor, a locoregional node, and liver metastases, demonstrating that patient has sufficient somatostatin receptor expression to qualify for PRRT, among other treatments. Arrow indicates normal pituitary uptake (P).

FIGURE 3

True-positive 68Ga-DOTATATE PET/CT with false-negative 111In-pentetreotide SPECT/CT. Anterior planar (A) image from 111In-pentetreotide SPECT/CT scan was negative for residual tumor. Anterior 3-dimensional maximum-intensity-projection view (B) and fused PET/CT (D) with skeletal metastatic foci prospectively missed on contrast-enhanced CT (C), verified with MRI (selected short-τ inversion recovery image, (E)). Patient was referred for PRRT, which would have been denied based on false-negative 111In-pentetreotide scan. Arrow indicates normal pituitary uptake (P).