Compare PET/CT and MRI for the early detection of bone metastases of prostate cancer: diagnostic performance and impact on the patient management.Determine the lowest cost strategy according to the precise clinical circumstances.

In patients with high risk prostate cancer and high PSA levels, PET/CT with fluoride (18F) and FLUOROCHOLINE (18F) and whole-body MRI will be performed within one month.

Data of a 6 month follow-up after those examination will be made available to a panel of independent experts. They will determine the standard of truth (SOT) concerning the invasion of the skeleton and also of soft tissue by prostate cancer tissue, the impact of each imaging modality on patient management and the adequacy of the decisions. In some cases (anti-hormone treatment without histology), it will not be possible to determine the SOT.

By comparison of the results of blind readings for each imaging modality with the standard of truth, the diagnostic performance will be determined.

By simulation, several strategies will be constructed concerning the best examinations to be performed and the sequence according to the precise clinical circumstances. Their cost and effectiveness will be evaluated.

Inclusion Criteria:

• Age > 18
• Histologically proven prostate cancer.
• Abnormal plasmatic level of prostate specific antigen dating less than 3 months, initial Gleason score available
• Written informed consent.

Exclusion Criteria:

• Other active cancer or bone infection.
• Chemotherapy or change in hormone therapy since the last PSA assay
• Contraindication to MRI without contrast agent (claustrophobia, pace maker, metallic foreign body, some cardiac valves). Metallic joint prostheses are NOT a contraindication.
• Allergic reaction to radiopharmaceuticals that will be used.
• Patient who seems not capable of staying in the gantry of the machines during the examinations without moving.

Prostate cancer