To determine early efficacy of bipolar radiofrequency ablation with a coil design (bRFA) for focal ablation of clinically significant localised prostate cancer (sPCa)visible at mpMRI.

A prospective IDEAL phase 2 development study (NCT02294903) recruited treatment naive patients with a single focus of localised sPCa (Gleason 7 or 4 mm or more of Gleason 6) concordant with a lesion visible on multi-parametric MRI. Intervention was a focal ablation with a bRFA system (Encage®, Trod Medical) encompassing the lesion and a predefined margin using nonrigid MRI-ultrasound fusion. Primary outcome was the proportion of men with absence of sPCa on biopsy at 6 months. Trial follow up comprised serum PSA, mpMRI at 1 week, 6 and 12 months post ablation. Validated patient reported outcome measures (PROMs) for urinary, erectile and bowel functions and adverse events monitoring system were used. Analyses were done on a per-protocol basis.

20 of 21 patients recruited received the intervention. Baseline characteristics were a median age of 66 years (IQR 63-69), pre-operative median PSA of 7.9 ng/ml (5.3-9.6), 18 (90%) had Gleason 7 with median maximum cancer of 7 mm (IQR 5-10) for a median 2.8 cc mpMRI lesions (IQR 1.4-4.8). Targeted biopsy of the treated area (median number of cores=6, IQR 5-8) showed absence of sPCa in 16/20 men (80%), concordant with mpMRI. There was a low profile of side effects at PROMs analysis and no serious adverse events.

Focal therapy of sPCa associated with an MRI lesion using bRFA showed early efficacy to ablate cancer with low rates of genitourinary and rectal side-effects.