Comparison of 18F-sodium fluoride PET/CT, 18F-fluorocholine PET/CT and diffusion-weighted MRI for the detection of bone metastases in recurrent prostate cancer: a cost-effectiveness analysis in France

Background The diagnostic performance of F-18-sodium fluoride positron emission tomography/computed tomography (PET/CT) (NaF), F-18-fluorocholine PET/CT (FCH) and diffusion-weighted whole-body magnetic resonance imaging (DW-MRI) in detecting bone metastases in prostate cancer (PCa) patients with first biochemical recurrence (BCR) has already been published, but their cost-effectiveness in this indication have never been compared. Methods We performed trial-based and model-based economic evaluations. In the trial, PCa patients with first BCR after previous definitive treatment were prospectively included. Imaging readings were performed both on-site by local specialists and centrally by experts. The economic evaluation extrapolated the diagnostic performances of the imaging techniques using a combination of a decision tree and Markov model based on the natural history of PCa. The health states were non-metastatic and metastatic BCR, non-metastatic and metastatic castration-resistant prostate cancer and death. The state-transition probabilities and utilities associated with each health state were derived from the literature. Real costs were extracted from the National Cost Study of hospital costs and the social health insurance cost schedule. Results There was no significant difference in diagnostic performance among the 3 imaging modalities in detecting bone metastases. FCH was the most cost-effective imaging modality above a threshold incremental cost-effectiveness ratio of 3000euro/QALY when imaging was interpreted by local specialists and 9000euro/QALY when imaging was interpreted by experts. Conclusions FCH had a better incremental effect on QALY, independent of imaging reading and should be preferred for detecting bone metastases in patients with biochemical recurrence of prostate cancer.