Pilot Study Evaluating the Role of Both PSMA and 64Cu-PET/CT Total Body in Patients With Locally Relapsed Prostate Cancer

PET/TC is a diagnostic tool potentially able to detect, in a single session, both local and distant disease. However, the sensitivity of 18-F-PET/CT in the identification of relapse on the prostatic bed, varies greatly and depends on the value of PSA with which the examination is carried out, the size of the relapse in the lodge, the acquisition protocol and it is limited by the physiological hyperaccumulation of the tracer in the bladder. The sensitivity of 18F-Choline PET/TC in our hands is significantly higher than the one that is generally reported in the literature (76% with PSA values >1 ng/ml after radical prostatectomy), but still lower than the one of mpMR. PET/CT with 64Cu exceeds the limits of 18F-choline PET/TC in the study of the prostatic bed, as the tracer used (64Cu) is not excreted by urinary route and therefore does not accumulate in the bladder.

This study has the following objectives:

Primary objective: - To evaluate the detection rate of both 64Cu-PET/CT and PSMA-PET/CT of relapses in patients undergoing radical prostatectomy and subsequent biochemical recurrence;

Secondary objectives are:

• to assess any change in radiation therapy strategy in terms of lesion delineation and dose distribution at planning.
• to evaluate the performance of both methods (mpMR and PSMA/64Cu-PET/CT) in assessing the response to radiotherapy with or without androgen deprivation