Background
Evaluating the efficacy of focal therapy for prostate cancer is limited by current approaches and may be improved with biological imaging techniques.
Conclusions
In a preclinical prostate cancer model, we show that 68Ga-PSMA PET/CT can identify and predict relapse earlier than blood PSA level. These findings support further testing in clinical trials. Patient summary: Positron emission tomography/computed tomography with gallium-68-labeled prostate-specific membrane antigen may be used to follow and evaluate treatment outcomes in men who receive focal therapy for prostate cancer.
Objective
We assessed whether positron emission tomography/computed tomography with gallium-68-labeled prostate-specific membrane antigen (68Ga-PSMA PET/CT) can be used to predict relapse after vascular-targeted photodynamic therapy (VTP). Design, setting, and participants: A total of 1×106 LNCaP cells were grafted subcutaneously in the flanks of 6-8-wk-old SCID mice. Of 24 mice with measurable tumors 6 wk after tumor implantation, 20 were treated with VTP (150mW/cm2) to ablate the tumors. Blood prostate-specific antigen (PSA) levels were assessed, and &sup6;&sup8;Ga-PSMA PET/CT images were performed 1 d before VTP and 1 and 4 wk after. Outcome measurements and statistical analysis: Local tumor relapse was evaluated by histology, and tumors were analyzed by prostate-specific membrane antigen (PSMA) and PSA immunohistochemistry. T tests and Kruskal-Wallis tests were used to determine significance.