Relation Between Intraprostatic Temperature and Clinical Outcome in Microwave Thermotherapy

Abstract

Purpose:

The study was designed to explore the relation between prostatic temperature and the clinical outcome of transurethral microwave thermotherapy (TUMT).

Patients and Methods:

Forty-nine patients with symptomatic benign prostatic hyperplasia (BPH) were treated. Baseline evaluation included Madsen score, flowmetry, and pressure-flow study. Two fiberoptic thermosensors were placed in the prostate targeted to the region 10 and 20 mm below the bladder neck and 5 to 15 mm lateral to the prostatic urethra. The TUMT was carried out using either the low-energy (2.0) or high-energy (2.5) Prostasoft program. Follow-up was at 6,12, and 26 weeks.

Results:

A moderate correlation between intraprostatic temperatures and energy output (r = 0.409; P ≤ 0.046) and prostate volume (r = 0.303; P ≤ 0.0424) was observed. Outlet obstruction was associated with higher temperatures (obstructed 49.6 ± 5.8 v unobstructed 46.1 ± 4.2°C; P ≤ 0.033). A significant relation between temperature and clinical outcome was found. Patients with intraprostatic temperatures <46°, 46−50°, and ≤50°C had significant differences in Madsen score change (−50%, −68% and −86%) and in maximum flow rate (+26%, +32%, and +48%). Patients with temperatures >50°C had a significant improvement in obstruction status (86% to 18%). A slight worsening in voiding dynamics was observed in patients with temperatures <50°C.

Conclusion:

A significant relation exists between intraprostatic temperatures achieved during TUMT and the clinical outcome. Temperatures in excess of 50°C seem to be associated with a greater improvement in lower urinary tract symptoms and bladder outlet obstruction. These data provide a sound rationale for monitoring intraprostatic temperatures and developing invasive thermometry feedback mechanisms for thermal treatments of BPH.