Dynamic 68Ga-PSMA and 18F-FDG PET/CT Analysis Prior to 177Lu-PSMA

Dynamic 68Ga-PSMA and 18F-FDG PET/CT Analysis of Metastatic Prostatic Adenocarcinomas Prior to 177Lu-PSMA Treatment

Prostate cancer is a significant health issue, representing 21.8% of male cancer cases in France with over 449,000 new cases in 2018. It's the cause of 10% of cancer deaths in Europe.

The PSMA is a target for mCRPC treatment, with therapies like 177Lu-PSMA-617 delivering radiation to cancer cells. The Vision study showed that 177Lu-PSMA-617, combined with standard care, improved survival rates significantly compared to standard care alone.The French ANSM authorized 177Lu-PSMA-617 for mCRPC under certain conditions. Patients must have histologically confirmed mCRPC, be progressive despite treatment, and have PSMA-positive imaging.

Imaging assessments include PSMA PET/CT and 18F-FDG PET/CT to identify FDG-positive and PSMA-negative sites, which are associated with a poorer prognosis.

Parametric analysis using dynamic PET could improve lesion characterization, aiding in treatment decisions. This is the focus of the PyPET study.

The main objective focuses on a comparative analysis of data from dynamic parametric analysis (metabolic influx rate Ki, volume of distribution Vd) and static analysis (standard at 1 hour) using 18F-FDG and 68Ga-PSMA PET/CT for diagnosing metastases, especially in the liver, lymph nodes, and bones. It aims to assess the effectiveness of these imaging techniques in accurately identifying metastatic sites.

Inclusion Criteria:

• Signed informed consent.
• Progressive metastatic castration-resistant prostate adenocarcinoma, which has been treated with taxane chemotherapy and at least one anti-androgen hormone therapy.
• Evaluated by 18F-FDG and 68Ga-PSMA PET/CT prior to potential treatment with 177Lu-PSMA.
• Affiliated with or beneficiary of a social protection scheme.
• WHO stage 0 or 1.

Exclusion Criteria:

• Patients unable to understand the study for any reason or comply with the trial requirements (due to language barriers, psychological issues, geographical constraints, etc.).
• Patients unable to undergo the examinations and/or maintain a prolonged lying position (due to back pain, etc.).