C11-acetate PET for docetaxel prednisone (DP) response assessment in castrate-resistant prostate cancer (CRPC).

83 Background: C11-acetate (acetate) positron-emission tomogram (PET) has shown promise in detection of metastasis in prostate cancer in recent studies. Our study tested the feasibility of acetate-PET to predict early response to DP in CRPC. Methods: Men with metastatic CRPC for whom DP was indicated were enrolled in a prospective study of acetate-PET imaging and bone scans. Patients (pts) were imaged with both modalities at study entry and after 3 cycles of DP. DP was continued beyond cycle 3 until PCWG2-defined progression or toxicity. Treating physicians were blinded to acetate-PET results. No pts were on statins. The study was IRB-approved. Results: 6 pts with documented bone metastases were imaged (5 both pre and post-therapy.) Pre-therapy acetate-PET identified osseous metastases in all 6 pts. Remarkably, in one pt with previous radiation therapy, pre-therapy acetate-PET was negative for disease in the radiated area whereas bone scan showed persistent activity. The median number of DP cycles was 7 (...