MR imaging-guided focal cryoablation in patients with recurrent prostate cancer.

PURPOSE: To assess the feasibility of magnetic resonance (MR) imaging-guided focal cryoablation in patients with locally recurrent prostate cancer after radiation therapy. MATERIALS AND METHODS: This was a prospective study, and informed consent was obtained from all patients. Ten consecutive patients with histopathologically proved recurrent prostate cancer after radiation therapy, without evidence of distant metastases, were treated while under general anesthesia in a 1.5-T MR unit. A urethral warmer was inserted. Cryoneedles were transperineally inserted under real-time MR imaging. Then, a rectal warmer was inserted. Ice ball growth was continuously monitored under MR imaging guidance. Two freeze-thaw cycles were performed. Follow-up consisted of a visit to the urologist, measurement of prostate-specific antigen level, and multiparametric MR imaging at 3, 6, and 12 months. Potential complications were recorded. RESULTS: All patients were successfully treated. In one patient, the urethral warmer could not be inserted and the procedure was cancelled. Two months later, the procedure was successfully repeated. Another patient had urinary retention. Follow-up data were available for all patients. A local recurrence or remnant tumor was found in two patients after 6 months and in another patient after 12 months. These three patients underwent successful retreatment with MR imaging-guided focal cryoablation. CONCLUSION: MR imaging-guided focal cryoablation of recurrent prostate cancer after radiation therapy is feasible and safe. Initial results are promising; however, longer follow-up is needed and more patients must be studied.