A reassessment of the clinical utility of 68Ga-DOTATATE PET/CT in patients with gastroenteropancreatic neuroendocrine tumors.

Abstract

e16294 Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a rare and biologically diverse group of tumors that can be challenging to image. Gallium-68 (Ga-68) DOTATATE positron emission tomography/computed tomography (PET/CT) is the most sensitive imaging tool for these tumors and has now been in clinical practice for over a decade. While its use has increased over time, its clinical impact remains unclear for specific stages of disease and indications for imaging. We sought to investigate this to provide information to guide its future use in clinical management. Methods: This retrospective cohort study identified adults with pathologically confirmed GEP-NETs between 1/1/2020 and 9/1/2022 at a tertiary care academic medical center. The electronic medical record was reviewed for demographic, clinical, and radiographic data. The primary objective was to determine if the use of 68Ga-DOTATATE PET/CT was associated with a change in clinical management, medical or surgical. The secondary objective was to determine if 68Ga-DOTATATE PET/CT was more effective in identifying primary or metastatic lesions compared to traditional imaging such as CT or magnetic resonance imaging (MRI) performed less than 90 days of the PET/CT scan. Percentages are reported with 95% Confidence Intervals (CI). Results: Overall, 124 patients with pathologically confirmed GEP NETs underwent a total of 207 68Ga-DOTATATE PET/CT scans. The majority (92.7%) of GEP NETs were moderately/well differentiated and the primary sites included the small intestine (50%), pancreas (23.4%), appendix/colon (8.9%), gastric (8.1%), mesentery (2.4%), and unknown (7.3%). Following PET/CT scan, 51 patients (41.1%; 95% CI = 32.4-49.8) had a change in clinical management, with the proportion of patients who had a change being higher among those with metastatic disease (44.9% vs 14.5%). Of the 124, 72 patients had traditional imaging 90 days or less prior to PET/CT available for comparison. In this subgroup, 34 patients (47.2%; 95% CI = 35.7-58.7) had new lesions identified on PET/CT that were not identified using traditional imaging and of the 34 patients with new lesions identified, 79.4% (95% CI = 66-93) had a change in their clinical management. The majority of these patients had M1 disease (50% vs 15.4%). Conclusions: This study highlights the impact of 68Ga-DOTATATE PET/CT imaging in the clinical management of patients with gastroenteropancreatic neuroendocrine tumors (GEP NETs). Notably this imaging technique resulted in a change in clinical management for 41% of these patients, particularly benefiting those with metastatic (M1) disease, where the change in management was more pronounced (44.9% vs. 14.5%). Furthermore, 68Ga-DOTATATE PET/CT proved superior to traditional imaging revealing new lesions in 47.2% of the patients, with the majority being patients with metastatic disease.