The Added Diagnostic Value of 18F-Fluorodihydroxyphenylalanine PET/CT in the Preoperative Work-Up of Small Bowel Neuroendocrine Tumors

Abstract

BackgroundThe precise localization of the primary tumor and/or the identification of multiple primary tumors improves the preoperative work-up in patients with small bowel (SB) neuroendocrine tumor (NET). The present study assesses the diagnostic value of 18F-fluorodihydroxyphenylalanine (18F-FDOPA) positron emission tomography/computed tomography (PET/CT) during the preoperative wok-up of SB NETs. MethodsBetween January 2010 and June 2017, all consecutive patients with SB NETs undergoing preoperative 18F-FDOPA PET/CT and successive resection were analyzed. Preoperative work-up included computed tomography (CT), somatostatin receptor scintigraphy (SRS), and 18F-FDOPA PET/CT. Sensitivity and accuracy ratio for primary and multiple tumor detection were compared with data from surgery and pathology. ResultsThere were 17 consecutive patients with SB NETs undergoing surgery. Nine patients (53%) had multiple tumors, 15 (88%) metastatic lymph nodes, 3 (18%) peritoneal carcinomatosis, and 9 patients (53%) liver metastases. A total of 70 SB NETs were found by pathology. Surgery identified the primary in 17/17 (100%) patients and recognized seven of 9 patients (78%) with multiple synchronous SB. Preoperatively, 18F-FDOPA PET/CT displayed a statistically significant higher sensitivity for primary tumor localization (100 vs. 23.5 vs. 29.5%) and multiple tumor detection (78 vs. 22 vs. 11%) over SRS and CT. Compared with pathology, 18F-FDOPA PET/CT displayed the highest accuracy ratio for number of tumor detected over CT and SRS (2.0±2.2 vs. 0.4±0.7 vs. 0.6 ± 1.5, p = 0.0003). Conclusion18F-FDOPA PET/CT significantly increased the sensitivity and accuracy for primary and multiple SB NET identification. 18F-FDOPA PET/CT should be included systematically in the preoperative work-up of SB NET.