Focal Therapy for Prostate Cancer

Multiparametric magnetic resonance imaging (mpMRI) is the standard imaging modality for prostate cancer diagnosis and focal therapy planning. However, 10-20% of clinically significant prostate cancers (csPCa) are not visible on mpMRI (PI-RADS 1-2). These MRI-invisible lesions, typically identified only on systematic biopsy, are currently not targetable by MRI-guided focal therapy, leaving patients with the choice between whole-gland radical treatment or active surveillance. This prospective, multi-centre, single-arm phase II trial investigates whether pelvis-only ¹⁸F-PSMA-1007 positron emission tomography-computed tomography (PET-CT) can identify MRI-invisible csPCa and serve as the therapeutic navigation tool for focal ablation. Men aged ≥50 years with localized, intermediate-risk prostate cancer (ISUP Grade Group 2-3) and at least one MRI-invisible csPCa focus undergo a PET-CT. If a PET-avid lesion corresponds anatomically to the MRI-invisible biopsy-positive site, the patient receives focal therapy using an energy modality (targeted microwave ablation, high-intensity focused ultrasound, or irreversible electroporation) selected based on tumour anatomy, guided by organ-based tracking. The primary endpoint is the absence of csPCa (Grade Group ≥2) on 6-month targeted biopsy of all treated zones. Secondary endpoints include out-of-field recurrence, functional outcomes, and safety. The study requires 45 treated patients (total enrolment \~60) across two Hong Kong centres and will be completed within 3 years.