The Role of 68Ga-DOTA-Octreotate PET/CT in Follow-Up of SDH-Associated Pheochromocytoma and Paraganglioma

Abstract Purpose Germline succinate dehydrogenase (SDHx) mutation carriers, especially SDHB, are at increased risk for malignancy and require life-long surveillance. Current guidelines recommend periodic whole-body MRI imaging. We assessed the incremental value of 68Ga-DOTA-octreotate (GaTate) positron emission tomography (PET)/CT compared with conventional imaging in such patients. Methods SDHx mutation carriers who had GaTate PET/CT were retrospectively reviewed. Detection of lesions were compared with MRI or CT on a per-patient and per-lesion basis. Proof of lesions were based on histopathology or clinical/imaging follow-up. Results Twenty consecutive patients (median age, 46 years; 10 males) were reviewed. Fourteen patients had SDHB, four, SDHD, one SDHC, and one SDHA mutation. Fifteen had prior surgery and/or radiotherapy. Indications for PET/CT were as follows: 7 patients for surveillance for previously treated disease, 9 residual disease, 2 asymptomatic mutation carriers, and 2 for elevated catecholamines. Median time between modalities was 1.5 months. GaTate PET/CT had higher sensitivity and specificity than conventional imaging. On a per-patient basis: PET/CT sensitivity 100%, specificity 100%; MRI/CT 85% and 50%. Per-lesion basis: PET/CT sensitivity 100%, specificity 75%; MRI/CT 80% and 25%. PET/CT correctly identified additional small nodal and osseous lesions. MRI/CT had more false-positive findings. Change of management resulted in 40% (8/20 patients): 3 received localized treatment instead of observation, 1 changed to observation given extra disease detected, 4 with metastases had radionuclide therapy. Conclusions GaTate PET/CT provided incremental diagnostic information with consequent management impact in SDHx-pheochromocytoma and paraganglioma. Incorporating this modality as part of a surveillance program seems prudent. Further research is needed to define the optimal surveillance strategy including use of MRI. We report the incremental diagnostic value with consequent management impact of GaTate PET/CT compared with MRI or CT in follow-up of patients with SDHx pheochromocytoma/paraganglioma.