Histopathology of prostatic tissue after transurethral hyperthermia

Abstract

Histopathological changes were studied in four patients who had moderate to severe urinary outflow obstruction due to benign prostatic hyperplasia (BPH) and were treated with transurethral microwave hyperthermia (TUMH). All these patients received TUMH with a helical antenna using a BSD 300 unit. The temperature was controlled on the urethral surface at 45 degrees C +/- 1 degree C. Each treatment session lasted 70 min at this temperature. Histological changes were periurethral, extending up to 6 mm radially and 4-5 cm longitudinally. They were symmetrical and most severe in the immediate periurethral zone. The severity and distribution of these histological changes correlated well with the thermal profile of the helical antenna. Acute changes, observed 24-48 h following administration of a single TUMH session, consisted of periurethral oedema, parenchymal haemorrhages and occasional, partial small-vessel thrombosis. Selective coagulation necrosis of the parenchymal smooth muscles with sparing of smooth muscle fibres in the vessel walls was noted. Histopathological changes found in patients 7 or 26 days following the administration of 10 TUMH treatments given twice-weekly for 5 weeks showed more severe and deeper lesions. They consisted of interstitial haemorrhages, complete obliteration of blood vessel lumina due to thrombosis and further evidence of coagulation and haemorrhagic necrosis. Evidence of a reparative process with ingrowth of granulation tissue in various stages of organization was clearly demonstrated. The effect of TUMH on BPH-obstructed urethra is probably expressed through selective shrinking and retraction of the periurethral prostatic parenchyma due to organizing localized tissue necrosis and cicatrization. Details of this complex process will be presented.

Transurethral Microwave Thermotherapy for Symptomatic Benign Prostatic Hyperplasia: Short-Term Experience with Prostcare

“…Since prostatic heating to less than 45°C cannot create permanent tissue change [7,14], TUMT was thus designed to achieve a therapeutic temperature of more than 45°C within the prostate for a treatment response. Despite the maximal intraprostatic temperature of 47.8 B 1.12°C that we were able to achieve in this study, the average radiometer temperature was only 41.6 B 1.78°C which may indicate that the duration of the effective therapeutic temperature is not long enough, and, therefore, the treatment became less effective.…”

In vitro Simulation of Thermotherapy for Benign Prostatic Hyperplasia by Fourier Transform Infrared Microspectroscopy Combined with Differential Scanning Calorimetry

“…FT-IR spectroscopy has been extensively applied to study the secondary structure of biological samples [20][21][22], Although thermotherapy or hyperthermia was suc cessfully used in BPH therapy, histological evidence and pathological lesions consisting of inflammatory edema, hemorrhagic vascular lesions with coagulative necrosis, glandular and smooth muscle necrosis have been reported [23]. However, basic studies on the conformational changes in the protein structure of BPH tissue are scant.…”

High-Energy Microwave Thermotherapy in the Treatment of Benign Prostatic Hyperplasia

“…A reduction was observed in the edematous reaction after a period of 2-3 weeks, with a collagen deposit progressively replacing the necrotic tissue and process of neoangiogenesis at the periphery of the lesion [15]. The coagulative necrosis of the transition area has a characteristic butterfly shape (parallel to that of the isothermic distribution curve) that forms the distinctive differentiation line of the HE-TUMT from the microwave or radiofrequency hyperthermia, the techniques causing at most superficial necrosis of the urethra or small randomly distributed areas of coagulation in the transition area [16]. In a European multicentric study in 1996, transrectal prostatic ultrasound showed cavitation in the transition area in 37% of patients undergoing HE-TUMT.…”