A Reassessment of the Clinical Utility of 68Ga-DOTATATE PET/CT in Patients With Gastroenteropancreatic Neuroendocrine Tumors.

Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a rare and biologically diverse group of tumors that are challenging to image. ⁶⁸Ga-DOTATATE PET/CT is the most sensitive imaging tool for these tumors, and while its use has increased over time, its clinical impact remains unclear, particularly for clinical scenarios involving surveillance after treatment. We sought to reassess its clinical utility across all stages.

Methods: Retrospective study of pathologically confirmed GEP-NET patients between 1/1/2020 and 9/1/2022 at a tertiary care center. Demographic, clinical, and radiographic data were analyzed. The primary objective was to determine if PET/CT use was associated with a change in clinical management. The secondary objective was to determine if PET/CT was superior in identifying primary or metastatic lesions compared to traditional imaging.

Results: One hundred twenty-four patients with GEP-NETs underwent 207 PET/CT scans. The majority of scans were obtained for disease surveillance (70.2%) or staging (37.9%), and the remaining (3.2%) were used to aid in diagnosis or before PRRT initiation (3.2%). Following PET/CT scan, 51 patients (41.1%) had a change in clinical management, with change being higher among those with metastatic disease (44.9% vs. 14.5%). Of the 124, 72 patients had traditional imaging available for comparison. In this subgroup, 34 patients (47.2%) had new lesions identified on PET/CT that were not identified using traditional imaging resulting in a change in management in 79.4% favoring patients with M1 versus M0 disease (26.9% M0 vs. 58.7% M1, p = 0.010).

Conclusion: ⁶⁸Ga-DOTATATE PET/CT imaging is clinically most useful for initial staging and in surveillance and monitoring response to therapy in the metastatic setting. It is least useful for surveillance in the early-stage setting and does not support its use following curative intent surgery. It remains superior to unlabeled imaging in sensitivity and the additional disease burden detected is highly likely to change management.