Objective To evaluate the safety of radiofrequency (RF) central temperatures reaching up to 105°C during 12 min of ablation; rectal temperature remained at energy delivered interstitially in patients with prostate cancer scheduled for radical prostatectomy and to <38°C. There were no complications. Macroscopic examination showed well-demarcated lesions includcorrelate the proposed theoretical lesion size with the pathological findings.ing the prostatic capsule, up to 2.2×1.5×4.5 cm. With monopolar energy, the observed lesion size was Patients and methods Radiofrequency interstitial tumour ablation (RITA) was performed in 15 patients comparable to the predicted 2×2×2 cm lesion, while with bipolar energy, lesion size was related to interwith localized prostate cancer before radical surgery. RF energy was delivered to the prostate by active needle distance and uncovered needle length. Microscopic examination showed clearly delineated needle electrodes (monopolar or bipolar) placed transperineally under transrectal ultrasonography guidlesions both with NADPH (in prostates immediately removed after surgery) and H&E (at 1 week after RITA) ance. Needle electrodes were used with diCerent configurations and in some cases were covered by staining. The lesion size observed on pathological analysis correlated with the predicted lesion size. In retractable shields to vary the length and circumference of the thermal lesions created. In eight patients, one patient, no residual cancer was found in the specimen. In the patient whose entire prostate was the procedure was performed immediately before radical prostatectomy, in six RITA was performed under targeted and followed by serial PSA measurements, the latter were undetectable at 3 months of follow-up. spinal anaesthesia 1 week before surgery and in one patient, no surgery was performed but the patient was Conclusion Transperineally delivered RF energy is capable of safely creating extensive coagulative necrotic followed by serial determinations of prostate specific antigen (PSA). At least two lesions were created in lesions in prostate cancer tissue, in a reproducible and controlled manner. The results presented here provide each prostate, including both capsule and peripheral zones. NADPH and haematoxylin & eosin (H&E) stainbasic information for the potential future application of this form of energy for localized prostate cancer. ing were used to assess the extent of the necrotic lesion in the radical prostatectomy specimen.Keywords Prostate cancer, radiofrequency, tumour ablation, transrectal ultrasonography Results The mean energy delivered was 10.5 kJ, with publicised in recent studies, can only be oCered to