Conductive heat: hot water-induced thermotherapy for ablation of prostatic tissue

Water-Induced Thermotherapy (WIT trade mark ) was developed to treat lower urinary tract symptoms (LUTS) and to reduce bladder outlet obstruction (BOO) secondary to benign prostatic hyperplasia (BPH). The principle is to produce heat-induced coagulative necrosis and secondary ablation of the obstructing hyperplastic tissue. The source of thermal energy is heated water circulated in a proprietary closed-loop system, which includes a specially designed catheter. To date, few papers on WIT have been published in peer-reviewed journals. The initial studies focused on feasibility and safety, while later ones were designed to demonstrate tissue and pathologic effects. In a prospective international study, 125 patients were enrolled at eight study centers and evaluated both short term (3, 6, and 12 months) and long term (24 and 36 months). The duration of indwelling catheterization was as follows: 45.5% of patients were catheter free after 1 week (the minimum required by the protocol), 30.5% after 2 weeks, and the remaining 24.0% after 3 to 5 weeks. No patients were asked to do intermittent catheterization. Adverse events were those commonly seen after manipulation of the lower urinary tract. International Prostate Symptom Score, Quality of Life score, peak uroflow rate (Q(max)), and postvoiding residual urine volume had improved significantly at 12, 24, and 36 months. Data reported in a more recent abstract indicate that favorable effects on symptoms and voiding parameters continue to at least 36 months. The WIT procedure was also associated with statistically significant post-treatment prostate shrinkage (median 3.2 cc) at 12 months compared with baseline. The reported failure rate and the rate of subsequent transurethral resection was 5.6% after 12 months, 9.6% after 24 months, and 11.2% after 36 months. According to the literature, WIT is a useful technique to treat BPH-related LUTS and BOO, with a success rate on an intention-to-treat basis of approximately 90% after 12 months and 75% after 24 months.