The role of [18F]F-DOPA PET/CT in diagnostic and prognostic assessment of medullary thyroid cancer: a 15-year experience with 109 patients

Abstract

Objective: Correct diagnosis and prognostic evaluation of medullary thyroid cancer (MTC) are crucial for the therapy of MTC. The purpose of this study was to evaluate the diagnostic and prognostic value of [18F]F-DOPA PET/CT in patients with MTC. Methods: We reviewed MTC patients who underwent [18F]F-DOPA PET/CT from June 2008 to November 2023. Clinical characteristics, follow-up data, and the following [18F]F-DOPA PET/CT parameters were recorded: maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumour volume (MTV), and SUVmean of multi-organs. The diagnostic value of PET/CT for detection of tumour lesions were calculated. Serum basal calcitonin (bCt) and stimulated calcitonin (sCt) were determined. Receiver operating characteristic (ROC), Kaplan–Meier and Cox regression analyses were performed. Results: 109 patients (50 women, 59 men; average age, 55 ± 14 y) were included in the analysis. The patient-related sensitivity, specificity and accuracy of [18F]F-DOPA PET/CT were 95%, 93% and 94%, respectively. The lesion-related sensitivity, specificity and accuracy were 65%, 99% and 72%, respectively. The optimal cutoff values of bCt, sCt and CEA to obtain positive [18F]F-DOPA PET/CT results were 64 pg/mL, 1808 pg/mL and 4 µg/L, respectively. Patients with negative [18F]F-DOPA PET/CT had longer overall survival (OS) than patients with positive [18F]F-DOPA PET/CT results (P=0.017). Significant positive correlations were found between bCt, sCt and CEA with SUVmax, SUVmean and MTV of [18F]F-DOPA PET/CT (P<0.001). [18F]F-DOPA PET/CT results and MTV may be useful for evaluation of prognosis of patients with recurrent MTC (RMTC). Conclusions: [18F]F-DOPA PET/CT had great value for diagnosis and prognostic assessment in patients with MTC. The DOPA PET/CT parameter SUVmean and MTV showed significant association to OS.