Transperineal microwave thermoablation in patients with obstructive benign prostatic hyperplasia: a phase I clinical study with a new mini-choked microwave applicator

PURPUSE: To evaluate the tolerability and safety of a newly designed probe for trans-perineal microwave thermoablation (TPMT) of the prostate in patients with benign prostatic hyperplasia (BPH), and the in vivo microwave effects on prostatic tissue. PATIENTS AND METHODS: Nine patients with obstructive BPH who were candidates for open prostatectomy were selected for this study. Under local anesthesia and transrectal ultrasound monitoring, all patients underwent a single standardized application of TPMT. The visual analog scale (VAS) and Short Form-36 health survey (SF-36) questionnaire were administered to each patient prior to, during, and 1 month after TPMT in order to evaluate pain and quality of life. Then the International Index of Erectile Function (IIEF-5) and International Prostate Symptom Score (IPSS) questionnaires were administered to each patient at baseline and 1 month after prostatectomy in order to evaluate sexual and urinary function, respectively. Then all patients were divided into three groups and underwent open prostatectomy 7, 15, and 30 days after TPMT, respectively. The prostatic adenomas were then evaluated by a pathologist. RESULTS: No adverse events from TPMT treatment were noted. In particular, no patients reported local, pelvic, or abdominal pain during the procedure or subsequent alterations of defecation rhythm, ano-rectal/intestinal problems, or hematuria. No differences in quality of life or in sexual function were reported. The diameters of the lesions obtained with TPMT treatment ranged from 16 to 18.1 mm in all patients. Quasi-spheroid lesions with a well-defined area of complete coagulative necrosis were documented in all removed adenomas 7, 15, and 30 days after TMPT. CONCLUSIONS: The AMICA-PROBE is a safe, well-tolerated, and repeatable method to treat BPH with microwave thermotherapy. The spheroid lesions obtained demonstrated the maximal control over the radial and longitudinal coagulative effects of the therapy. Phase II studies are needed to further evaluate the efficacy of this new probe.