Detailed interstitial temperature mapping during treatment with a novel transurethral microwave thermoablation system in patients with benign prostatic hyperplasia

Minimally invasive devices for treating lower urinary tract symptoms in benign prostate hyperplasia: technology update

Benign prostatic hyperplasia (BPH) represents a spectrum of related lower urinary tract symptoms (LUTS). The cost of currently recommended medications and the discontinuation rate due to side effects are significant drawbacks limiting their long-term use in clinical practice. Interventional procedures, considered as the definitive treatment for BPH, carry a significant risk of treatment-related complications in frail patients. These issues have contributed to the emergence of new approaches as alternative options to standard therapies. This paper reviews the recent literature regarding the experimental treatments under investigation and presents the currently available experimental devices and techniques used under local anesthesia for the treatment of LUTS/BPH in the vast majority of cases. Devices for delivery of thermal treatment (microwaves, radiofrequency, high-intensity focused ultrasound, and the Rezum system), mechanical devices (prostatic stent and urethral lift), fractionation of prostatic tissue (histotripsy and aquablation), prostate artery embolization, and intraprostatic drugs are discussed. Evidence for the safety, tolerability, and efficacy of these "minimally invasive procedures" is analyzed.

[BPH: state of the art in the surgical treatment]

TURP has been considered the gold standard for surgical treatment of BPH for many years. Symptoms relief, improvement in maximum flow rate and reduction of post void residual urine have been reported in several experiences. Nevertheless, concerns have been reported in terms of safety outcomes: intracapsular perforation, TUR syndrome, bleeding. In the recent years the use of new forms of energy and devices such as bipolar resector, Ho: YAG and potassium-titanyl-phosphate laser are challenging the role of traditional TURP for BPH surgical treatment. In 1999 TURP represented 81% of surgical treatment for BPH versus 39% in 2005. We have analyzed guidelines and recent literature to evaluate the role of the most relevant new surgical approaches compared to TURP for the treatment of BPH.

Recent advances in the surgical treatment of benign prostatic hyperplasia

TURP for many years has been considered the gold standard for surgical treatment of BPH. Symptoms relief, improvement in Maximum flow rate and reduction of post void residual urine have been reported in several experiences. Notwithstanding a satisfactory efficacy, concerns have been reported in terms of safety outcomes:intracapsular perforation, TUR syndrome, bleeding with a higher risk of transfusion particularly in larger prostates have been extensivelyreported in the literature.IN THE RECENT YEARS THE USE OF NEW FORMS OF ENERGY AND DEVICES SUCHAS BIPOLAR RESECTOR, HO: YAG and potassium-titanyl-phosphate laserare challenging the role of traditional TURP for BPH surgical treatment.In 1999 TURP represented the 81% of surgical treatment for BPHversus 39% of 2005. Is this a marketing driven change or is there areal advantage in new technologies?We analyzed guidelines and higher evidence studies to evaluate therole of the most relevant new surgical approaches compared to TURPfor the treatment of BPH.In case of prostates of very large size the challenge is ongoing, withminimally invasive laparoscopic approach and most recently roboticapproach. We will evaluate the most recent literature on thisemerging field.

Interstitial temperature mapping during Prolieve transurethral microwave treatment: Imaging reveals thermotherapy temperatures resulting in tissue necrosis and patent prostatic urethra

OBJECTIVES

Temperature mapping of the prostate during transurethral microwave thermotherapy and imaging of the resultant zones of tissue necrosis have been previously performed using several commercial systems. This study was performed using the Prolieve Thermodilatation System, which simultaneously compresses the prostate with a 46F balloon circulating heated fluid and delivering microwave energy into the prostate.

METHODS

Interstitial temperature mapping during Prolieve treatment was performed on 10 patients with benign prostatic hyperplasia using 24 temperature sensors arrayed throughout the prostate. Voiding cystourethrograms were performed on 3 additional patients treated without temperature mapping to document the patency of the prostatic urethra 1 hour after treatment. Gadolinium-enhanced magnetic resonance imaging studies were performed on all patients 1 week after treatment to determine the extent and pattern of tissue necrosis resulting from transurethral microwave thermotherapy.

RESULTS

Interstitial temperature mapping found that the heating pattern generated by the Prolieve system created average peak temperatures of 51.8 degrees C an average of 7 mm away from the prostatic urethra. These temperatures were greater near the bladder neck and mid-gland than toward the prostatic apex. Subtherapeutic temperatures were seen adjacent to the urethra, consistent with the viable tissue seen on gadolinium-enhanced magnetic resonance imaging sequences. Magnetic resonance imaging also revealed necrotic zones that were consistent with sustained temperatures greater than 45 degrees C. Voiding cystourethrograms showed widely patent prostatic urethras 1 hour after treatment.

CONCLUSIONS

Transurethral microwave thermotherapy with the Prolieve Thermodilatation System produced sustained therapeutic temperatures that resulted in tissue necrosis while maintaining viable tissue surrounding a temporarily dilated prostatic urethra.

Efficacy of high-energy transurethral microwave thermotherapy in alleviating medically refractory urinary retention due to benign prostatic hyperplasia

OBJECTIVES

To determine the efficacy of high-energy transurethral microwave thermotherapy (HE-TUMT) in treating patients with medically refractory complete urinary retention secondary to benign prostatic hyperplasia (BPH).

METHODS

Between April 2000 and July 2003, 39 patients in urinary retention due to BPH were treated with HE-TUMT. A Foley catheter was reinserted after HE-TUMT and removed at 3 weeks for a voiding trial. Patients unable to void were recatheterized, and voiding trials were repeated at 2-week intervals. Patients were evaluated according to history and physical examination, prostate-specific antigen level, prostate volume, cystourethroscopy, International Prostate Symptom Score, quality of life score, peak uroflow, and postvoid residual. Success was defined as the ability to urinate after HE-TUMT without the need for further intervention.

RESULTS

The mean (+/- SD) patient age was 72 +/- 9.3 years. Mean follow-up period was 18 +/- 10.2 months. Twenty patients (51%) were characterized as American Society of Anesthesiologists class III or higher. The mean prostate volume was 75.2 +/- 57.6 cm3. The mean length of time that patients were dependent on indwelling Foley catheters before HE-TUMT was 9.6 +/- 14.2 weeks. Thirty-two patients were able to void after HE-TUMT, for an overall success rate of 82%. Patients voiding successfully after HE-TUMT had a mean of 1.6 +/- 0.8 voiding trials and required catheters after HE-TUMT for a mean period of 4.1 +/- 2 weeks. Only 6 (15%) of the patients who were voiding were able to stop their medication for BPH.

CONCLUSIONS

We found an encouraging success rate with HE-TUMT in relieving urinary retention in patients with BPH, including those with large prostate volumes. It is an acceptable option for patients who are considered high risk for surgery. Several patients required multiple voiding trials before spontaneous urination, which suggests that improvements in bladder outlet obstruction might require a prolonged period after HE-TUMT. Finally, many patients might require continued use of medications after HE-TUMT.

Cooled transurethral microwave thermotherapy for intractable chronic prostatitis--results of a pilot study after 1 year

OBJECTIVES

To evaluate the side effects, tolerability, and efficacy of transurethral microwave thermotherapy with urethral cooling (cooled TUMT) for chronic prostatitis/chronic pelvic pain syndrome in a prospective feasibility trial. Cooled TUMT, using the Targis system from Urologix, is an established treatment option for benign prostatic hyperplasia (BPH) with minimal side effects.

METHODS

Patients with intractable chronic prostatitis/chronic pelvic pain syndrome and symptoms for more than 3 of the 6 months before treatment (National Institutes of Health-Chronic Prostatitis Symptom Index [NIH-CPSI] pain score of at least 8) were randomized to cooled TUMT at an intraprostatic temperature of either approximately 55 degrees C or approximately 70 degrees C. Tolerability, side effects, and efficacy were measured with standard diagnostic tests, including the NIH-CPSI. Subgroup analysis was performed to evaluate the effects with and without BPH comorbidity.

RESULTS

A total of 42 patients were included in the study; 39 patients successfully completed treatment and 35 completed follow-up through 12 months. The baseline versus 12-month mean NIH-CPSI score was total score 23.4 +/- 6.4 versus 11.5 +/- 10.2 (improvement in mean value of 51%), pain score 11.5 +/- 2.8 versus 4.6 +/- 4.9 (improvement in mean value of 60%), quality-of-life impact score 7.2 +/- 2.9 versus 3.8 +/- 3.8 (improvement in mean value of 47%; all P <0.0001), and urinary score 4.7 +/- 2.8 versus 3.1 +/- 3.0 (improvement in mean value of 34%; P = 0.0079). Treatment discomfort was within the ranges reported for patients with Targis-treated BPH. Two patients had reduced sperm motility. Side effects were minimal and transient, resolved spontaneously or with medication, and were similar regardless of treatment temperature or BPH comorbidity.

CONCLUSIONS

Cooled TUMT appears to be promising for intractable chronic prostatitis with or without BPH. Longer follow-up and a larger trial are required to evaluate the fertility impact and longer term durability further.

Feedback microwave thermotherapy with the ProstaLund Compact Device for obstructive benign prostatic hyperplasia: 12-month response rates and complications

PURPOSE

To evaluate the effectiveness of the ProstaLund Compact Device in the treatment of benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

A series of 38 consecutive patients with a mean age of 72.6+/-8.2 years, 19 with an indwelling catheter, underwent transurethral microwave thermotherapy (TUMT) with the ProstaLund Compact Device. Pretreatment evaluation included transrectal ultrasonography (TRUS), urodynamics, and cystoscopy for all patients and flow rate (Qmax), postvoiding residual urine volume (PVR), International Prostate Symptom Score (IPSS), and quality-of-life (QoL) assessment for those without a catheter. The mean prostate volume was 63.5+/-30 cc. The Qmax, IPSS, and QoL studies were repeated at 3, 6, and 12 months, while urodynamics, cystoscopy, and TRUS were repeated at 6 and 12 months.

RESULTS

The treatment lasted a mean of 43.1+/-17.1 minutes, achieved a maximal intraprostatic temperature of 58.7+/-7.2 degrees C, and destroyed 18.4+/-14.3 g of prostatic tissue. Twelve months post-treatment, for the patients without a catheter preoperatively, the IPSS was improved from 21.5+/-6.3 to 6.5+/-3.1 (P<0.001), Qmax from 7.2+/-3.1 mL/sec to 18.1+/-7.4 mL/sec (P<0.001), detrusor pressure at Qmax from 87.5+/-15 cm H2O to 48.4+/-16.4 cm H2O (P<0.001), and PVR from 113.2+/-78.2 mL to 34.6+/-36.7 mL (P<0.01). The good-response rates for IPSS (<or=7 or >or=50% improvement), Qmax (>or=15 mL/sec or >or=50% improvement), PVR (<50 mL or >or=50% decrease), and QoL (<or=2) were 73.7%, 84.2%, 73.7%, and 94.7%, respectively. For the patients with a catheter preoperatively, the IPSS improved from 9.5+/-6 at 3 months to 5.1+/-5.3 (P<0.05) at the end of the follow-up period. The Qmax was 13.2+/-6.4 mL/sec at 3 months and remained stable throughout the follow-up period. Patient good-response rates for IPSS (<or=7), PVR (<150 mL), and QoL (<or=2) were 75%, 87.5% and 75%, respectively. Only two patients were unable to void after the treatment. Complications were similar to those presented in the literature, and bladder stone formation was noted as well (five patients).

CONCLUSIONS

ProstaLund thermotherapy is a highly promising alternative treatment for BPH, improving substantially both objective and subjective measures of bladder outflow obstruction.

Application of External Microwave Thermotherapy in Urology: Past, Present, and Future

The excellent clinical results of transurethral microwave thermotherapy (TUMT) for the treatment of symptomatic benign prostatic hyperplasia (BPH) gave to TUMT the leading position among the microwave thermotherapy modalities available for the treatment of different urologic conditions. Research in TUMT has focused on operating software, temperature monitoring, intraprostatic heat distribution, cell-kill calculations, and correlations with clinical variables. Randomized comparisons of TUMT with other established therapies for BPH, including transurethral resection, have facilitated the evaluation of the clinical outcome, durability, morbidity, and costs of the treatment. The applications of microwave thermotherapy in other urologic diseases are also presented in this review.

Fast liquid ablation system for prostatic hyperplasia: a new minimally invasive thermal treatment

PURPOSE

We determined patient tolerance and the sequence of histopathological changes of thermal injury and healing of the prostate after treatment with a novel, rapid, high temperature, liquid filled, flexible balloon thermotherapy system.

MATERIALS AND METHODS

A total of 17 patients scheduled for prostatic surgery received preoperative high temperature water balloon thermotherapy. In 13 patients intraprostatic, urethral and rectal temperatures were continuously monitored and determined using stereotactic thermal mapping with the patient under spinal anesthesia. The remaining 4 patients had lidocaine gel as the only method of pain control. Patient discomfort was recorded at all times during the procedure. After treatment a prostatic stent was left in place until surgery or spontaneous voiding. Serial sections of the resected prostates were evaluated pathologically with mapping.

RESULTS

Treatment was well tolerated by all patients. Prostates were enucleated (in 12 patients) or entirely removed (in 5) at a mean of 35 days (range 15 to 173) after thermotherapy. The predominant pathological findings in the early phase were uniform periurethral hemorrhagic necrosis, extensive urothelial denudation and varying degrees of inflammation. The mean radial depth of necrosis (from the urethra to the viable tissue border) was 0.9 cm (range 0.6 to 1.5) involving a mean of 16% of the prostatic adenoma (range 7.8% to 32%). In the late (resolution) phase necrotic tissue had been replaced by scar tissue (fibrosis and hyalinization) with a mean radial depth of 0.13 cm (range 0.01 to 0.24), and the urothelium had largely regrown along the urethra.

CONCLUSIONS

The fast liquid ablation system for hyperplasia is a new minimally invasive treatment that induces considerable thermal injury to the prostate with uniform necrosis and subsequent sloughing of dead tissue, allowing enlargement of the urethral lumen.

Histological changes of minimally invasive procedures for the treatment of benign prostatic hyperplasia and prostate cancer: clinical implications

PURPOSE

Benign prostatic hyperplasia (BPH) is near universal in aging men, creating tremendous costs in morbidity and surgical treatment. In the last decade numerous nonsurgical minimally invasive methods have emerged for ablation of prostatic tissue.

MATERIALS AND METHODS

We reviewed the recently published English language literature on minimally invasive techniques for treating BPH and cancer with an emphasis on histopathological findings.

RESULTS

We compared the spectrum of contemporary minimally invasive treatments for BPH and cancer, with an emphasis on histopathological results. Clinical results were summarized briefly for each treatment method. These procedures ablate tissue by thermal, cryogenic, chemical or enzymatic injury. The 5-year results for some techniques were promising, although long-term durability is still uncertain, and other methods were in preclinical or early clinical stages. Invariably the treated tissue was devitalized with a thin border of granulation tissue and fibrosis. These procedures have applications for BPH and prostate cancer, although some studies are limited to only 1 disease.

CONCLUSIONS

Minimally invasive procedures show promise of a durable replacement for surgical resection.

Transurethral microwave thermotherapy (TUMT) with the Targis System: a single-centre study on 78 patients with acute urinary retention and poor general health

OBJECTIVES

To evaluate the Targis System in men presenting with acute urinary retention, high prostate volume and high operative risk.

MATERIALS AND METHODS

Between August 1997 and March 2001, a total of 78 patients in poor general health status presenting with large prostate glands and acute urinary retention secondary to BPH were treated with the Targis TUMT device. Mean age, mean prostate volume, and the percentage of patients who were able to urinate spontaneously after the procedure as well as mean peak and average flow rates and mean residual urine volume were evaluated.

RESULTS

68 (87.1%) of the 78 patients were able to urinate spontaneously three months after the procedure. In 5 (7.3%) of the 68 patients urinary retention recurred within two years. Following treatment, the mean peak flow rate in the 68 successfully treated patients was 11.1 ml/s, while the mean postvoid residual volume was 46 ml.

CONCLUSION

Based on these data we recommend transurethral thermotherapy using the Targis System for patients in poor general health presenting with urinary retention and prostate volumes of more than 35 cc in whom TURP is not possible.

Quantification of prostate shrinkage after microwave thermotherapy: a comparison of calculated cell-kill versus 3D transrectal ultrasound planimetry

PURPOSE

To compare prostate shrinkage after transurethral microwave thermotherapy (TUMT) with calculated cell-kill.

MATERIALS AND METHODS

The calculated cell-kill from 33 males with benign prostatic hyperplasia (BPH) treated with TUMT according to the ProstaLund Feedback Treatment (PLFT) method was compared to the post-treatment prostate volume change. The prostate volume was estimated with three-dimensional transrectal ultrasound (3D-TRUS) planimetry at baseline, 3, 6, and 12 months follow-up. A paired t-test was used to test the statistical significance of differences between the cell-kill volume and the prostate volume change. Linear regression was used to infer a relationship between the cell-kill and the 3D-TRUS data. The reproducibility of the 3D-TRUS method was assessed in repeated measurements.

RESULTS

The mean prostate volume at baseline (N=33) was 56.1cm(3). After 3 (N=25), 6 (N=29) and 12 months (N=23), it was 45.5 cm(3), 39.7 cm(3), and 45.1cm(3), respectively. The corresponding average cell-kill volume was 16.4 cm(3), 17.1cm(3), and 17.2 cm(3), respectively. Predicted cell-kill volume was significantly larger than prostate shrinkage at 3 (p<0.0001), 6 (p=0.0002), and 12 months (p<0.0001), and showed a strong correlation at 3 and 6 months (r=0.74, p<0.0001). Correlation at 12 months was moderate (r=0.57, p=0.0041). Examination and investigation variability both averaged 2.5%.

CONCLUSIONS

Cell-kill calculations of the PLFT method are proportional to the 3D-TRUS prostate shrinkage by a factor of 0.5 and have a precision of approximately +/-10 cm(3) for 90% of the patients during the first year after treatment.

Heat versus drugs in the treatment of benign prostatic hyperplasia

The improvement in symptoms and voiding function is greater with transurethral microwave thermotherapy than with drug therapy, and the associated morbidity is low. Transient urinary retention necessitating catheterization is of short duration after targeted microwave thermotherapy. The short-term effect of microwave thermotherapy can be improved by neoadjuvant and adjuvant alpha-blockade. Microwave treatment offers greater versatility than drug therapy, allowing patients with severe baseline symptoms and small prostates to be treated successfully. Medical management improves symptoms to a more modest extent than does microwave treatment. Finasteride gives comparatively small symptom and flow rate improvements and requires several months for the maximum responses. With alpha-blockers the onset of action is fast and side-effects reversible, although they limit their utility. Finasteride or alpha-blockers must be continued indefinitely to maintain improvements in patients with BPH, but they have a favourable safety and tolerability profile.

Rationale and assessment of minimally invasive approaches to benign prostatic hyperplasia therapy

Benign prostatic hyperplasia affects quality of life, with most patients complaining of symptoms related to urination. For this reason, successful treatments can be defined by (1) their effect on lower urinary tract symptoms, (2) their impact on quality of life, and (3) their ability to unobstruct the flow of urine through the prostate. Minimally invasive therapy (MIT), which includes transurethral microwave thermotherapy, water-induced thermotherapy, interstitial devices (eg, transurethral needle ablation), and interstitial laser treatments, offers physicians and their patients cost-effective alternatives for achieving a substantially improved quality of life at an acceptable level of risk. Evidence-based medicine indicates that MIT is safe and achieves significant symptomatic improvement. Compared with long-term medical management, minimally invasive procedures offer effective, well-tolerated 1-time intervention with lasting effects that can be achieved on an outpatient basis. This article reviews the options for MIT.

Minimally invasive procedures as an alternative to medical management for lower urinary tract symptoms of benign prostatic hyperplasia

Data are reviewed relating to the safety and efficacy of minimally invasive transurethral microwave thermotherapy and medical management in patients with lower urinary tract symptoms of benign prostatic hyperplasia. Recent evidence is summarized indicating more pronounced long-term beneficial effects of microwave treatment. alpha-Blockade, however, offers the advantage of more rapid action than microwave treatment. Neoadjuvant and adjuvant alpha-blocker therapy can accelerate symptom and flow rate improvement in patients receiving microwave treatment. Compared with medical management, microwave treatment possesses greater versatility, allowing patients with severe baseline symptoms and small prostate sizes to be treated with a high probability of success.

Correlation between central zone perfusion defects on gadolinium-enhanced MRI and intraprostatic temperatures during transurethral microwave thermotherapy

BACKGROUND AND PURPOSE

The likelihood of success of thermoablation of prostatic hyperplasia depends on delivering an optimal thermal dose, but data on the temperatures achieved with these methods are few. We sought to develop a noninvasive method for monitoring intraprostatic heat distribution.

PATIENTS AND METHODS

Thirteen patients ranging from 50 to 76 (mean 61.3+/-8.1) years were enrolled in this study, all of whom had evidence of obstruction by uroflowmetry and pressure-flow studies. The mean total volume of the gland was 40.3+/-13.1 cc, while the mean adenoma volume was 20.4+/-10.1 cc, as estimated by preoperative transrectal ultrasonography. All the patients were treated with the Urologix Targis device for at least 45 minutes. Continuous temperature mapping was performed during the therapy using spatially dispersed thermosensors at 16 prostatic sites. The patients were evaluated 5 to 12 days postoperatively with MRI of the prostate utilizing a pelvic phased-array coil at 1.5 T.

RESULTS

Postprocedure MRI demonstrated a mean perfusion defect of 28.1+/-2.1% and 63.6+/-34% of the total gland and transition zone volumes, respectively. The mean anteroposterior (AP) and transverse diameters of the perfusion defects, as measured on the MRI images, were 29.2+/-5.2 mm and 32.7+/-5.9 mm, respectively. The maximum mean peak temperatures were 66.8+/-13 degrees C and were recorded at 4 mm from the urethra. No temperatures higher than 45 degrees C were recorded beyond 15 mm on either side of the urethra in the AP direction and beyond 16 mm on either side of the urethra in the transverse diameter. This perfusion defect was persistent for 27.7+/-5.2 mm in the superoinferior diameter, which is equivalent to the length of the antenna (28 mm).

CONCLUSION

Perfusion defect diameters as measured by postprocedure MRI accurately represent the prostatic tissues exposed to temperatures of > or =45 degrees C for 45 minutes or more. So, MRI provides an accurate, noninvasive method for screening the effective heat pattern generated in the prostate during transurethral microwave thermotherapy.

Microwave thermotherapy: historical overview

The application of heat with curative aim is an old and very well-known principle in medicine. A review of the history of heat use in the treatment of prostatic disease is presented. The article is based on bibliographic research (MEDLINE Search and PubMed) and focuses on treatment of benign prostatic hyperplasia (BPH) since the first clinical documentation of transrectal hyperthermia for this condition. Then, in a chronological sequence, not only the evolution toward thermotherapy but also enhancements of the latest techniques are presented. The new advances in the field of patient selection, indications, and outcome predictors, as well as new trends in treatment are briefly considered.

Intraprostatic temperature monitoring during transurethral microwave thermotherapy: status and future developments

Transurethral microwave thermotherapy is being applied as a minimally invasive treatment for alleviating the symptoms of urinary outlet obstruction associated with benign prostatic hyperplasia. Treatment progress has traditionally been guided in its effective power by rectally and urethrally measured temperatures, whereas intraprostatic temperatures would be preferred for feedback purposes. A critical evaluation is presented of intraprostatic thermometry techniques that have been suggested, the techniques currently being used and investigated, and the problems that remain to be solved. Techniques for noninvasive temperature measurement and detecting tissue response during thermal therapy are discussed in more detail. Results presented in the literature have shown magnetic resonance imaging and ultrasonic imaging to be adequate thermometry modalities. For treatment monitoring of transurethral microwave thermotherapy, ultrasonic imaging is especially promising. Future research will indicate whether the promise evolves into a sound clinical technique.

Transurethral microwave thermotherapy: an alternative to medical management in patients with benign prostatic hyperplasia?

Transurethral microwave thermotherapy (TUMT) is being increasingly considered as an alternative to medical management with alpha-blockers or finasteride in patients with lower urinary tract symptoms (LUTS) of benign prostate hyperplasia (BPH). Enduring clinical benefits have been demonstrated after a single 1-hour microwave treatment session under topical anesthesia, and the associated morbidity is low. Optimal results are obtained with the delivery of high thermal doses and accurate targeting of microwave energy. Extensive evidence from randomized clinical trials supports the safety and efficacy of both microwave treatment and medical management, but randomized trial data have only recently become available directly comparing these two approaches to BPH treatment. These data indicate that greater long-term improvements in symptoms, peak urinary flow rates, and quality of life are attained with microwave treatment than with alpha-blockade. Furthermore, the actuarial rate of treatment failure is markedly lower in patients undergoing microwave v alpha-blocker treatment. However, the onset of action of alpha-blocker treatment is more rapid. The principal limitations of alpha-blockade are side effects and lack of efficacy leading to treatment failure in some patients. The maximal effects of finasteride are modest and require a period of months to be manifested, although the side effect profile and tolerability of this agent are favorable. Neoadjuvant and adjuvant alpha-blocker therapy can accelerate symptom and flow rate improvement after TUMT. In contrast to medical management, microwave treatment is highly versatile, allowing patients over a broad range of baseline symptom severities and prostate sizes to be treated with a high probability of success.

Does transurethral microwave thermotherapy have a different effect on prostate cancer than on benign or hyperplastic tissue?

OBJECTIVES

Transurethral microwave thermotherapy is useful for the treatment of benign prostatic hyperplasia, but its effect on cancer is not documented. We analyzed the pathologic changes occurring after microwave thermotherapy in whole mount radical prostatectomy specimens from patients with cancer.

METHODS

Nine patients scheduled for radical prostatectomy for clinically localized prostate cancer were treated with transurethral microwave thermotherapy (Urologix Targis System). Patients ranged in age from 64 to 72 years (mean 68). Seven patients underwent prostatectomy 4 to 90 hours after thermotherapy, and 2 other patients underwent prostatectomy 12 months after thermotherapy. Whole mount totally embedded prostates were mapped for necrosis and cancer, and the volume of each was measured by the grid method.

RESULTS

Pathologic stages were T2a (n = 4), T2b (n = 4), and T3b (n = 1). The prostates from patients who underwent radical prostatectomy within 4 to 90 hours of thermotherapy had a mean prostate weight of 47.4 g (range 19.5 to 70.3). Each consistently showed hemorrhagic necrosis and tissue devitalization without significant inflammation. Necrosis involved contiguous areas of benign epithelium, stroma, and cancer without skip areas. The mean volume of necrosis was 8.8 cc (range 1.4 to 17.8), and the mean percentage of the prostate involved by necrosis was 22% (range 3% to 39%). The necrosis was symmetric around the urethra in 6 of 7 cases. Urethral dilation was observed in 3 patients, and the mean maximum radial distance of necrotic tissue was 1.4 cm (range 0.6 to 1.8). Necrotic change was noted in 80% to 100% of the volume of cancer in 4 cases, 40% to 60% in 2 cases, and 5% in 1 case. The prostates from the 2 patients who underwent radical prostatectomy 12 months after thermotherapy had a mean weight of 88 g (55 and 121 g, respectively). Each showed periurethral fibrosis, nonspecific chronic inflammation, and squamous metaplasia of the urothelium. The mean volume of necrosis remaining was 0.2 cc. The mean percentage of the prostate involved by necrosis 1 year after thermotherapy was less than 1%. There was some reabsorption of dead tissue. The mean maximum radial distance of the necrotic tissue was 0.4 cm (0.2 and 0.7 cm, respectively). The prostatic urethra had viable and partially denuded urothelium in all cases.

CONCLUSIONS

Microwave thermotherapy is clinically useful for ablation of benign prostate and cancer contiguous to the urethra, resulting in hemorrhagic necrosis with minimal damage to the urethra. There was no apparent differential morphologic sensitivity of benign prostatic tissue, hyperplastic tissue, or cancer to thermotherapy.

Transurethral microwave thermotherapy: what role should it play versus medical management in the treatment of benign prostatic hyperplasia?

Both transurethral microwave thermotherapy (TUMT) and medical management by alpha-blockade or 5-alpha-reductase inhibition are increasingly being considered as alternatives to surgery for treatment of patients with benign prostatic hyperplasia (BPH). We review current evidence supporting the effectiveness and safety of TUMT and medical management. Factors for consideration in appropriately selecting patients for TUMT versus medical management are suggested. Available data indicate that TUMT confers greater long-term benefits than medical management as judged by symptom score and peak urinary flow rate improvements. TUMT-associated morbidity is comparatively low. Alpha-blockade affords more rapid relief than TUMT for patients with BPH; however, other strategies such as the use of temporary intraurethral endoprostheses during the acute post-TUMT recovery period may diminish or abolish the differences in time-course of symptom and flow rate improvement between TUMT and alpha-blockade. 5-Alpha-reductase inhibition with finasteride offers a favorable side-effect profile, although the magnitude of symptom and flow rate improvements is modest, and maximal effects of finasteride do not become manifest until after several months of treatment. As TUMT continues to evolve, increasing attention is being accorded the delivery of high thermal doses and precise targeting of the thermal energy delivered. The development of alpha-blockers with a more favorable side-effect profile continues to be a major focus of investigation. The potential clinical utility of combination therapy with TUMT and alpha-blockade is currently under investigation.

Tolerability of high energy transurethral microwave thermotherapy with topical urethral anesthesia: results of a prospective, randomized, single-blinded clinical trial

PURPOSE

We determine the tolerability of high energy transurethral microwave thermotherapy with topical urethral anesthesia alone without supplementary systemic sedoanalgesia.

MATERIALS AND METHODS

A total of 45 patients with symptomatic benign prostatic hyperplasia were randomized to high energy transurethral microwave thermotherapy using either topical urethral anesthesia alone (topical anesthesia group) or topical anesthesia with adjunctive intravenous sedoanalgesia (sedoanalgesia group). Pain was evaluated sequentially by means of a 0 to 10 visual analog scale score. Posttreatment followup included determinations of International Prostate Symptom Score, peak flow rate, post-void residual urine, and quality of life score at 6 and 12 weeks.

RESULTS

Upon commencement of microwave treatment mean visual analog scale score was 1.3 (95% confidence interval [CI], 1.0 to 1.7) in the sedoanalgesia group and 1.4 (95% CI, 1.0 to 1.9) in the topical anesthesia group. During therapy visual analog scale score increased to a peak at 30 minutes of 2.0 (95% CI, 1.6 to 2.4) and 2.2 (95% CI, 1.7 to 2.6) in the sedoanalgesia and topical anesthesia groups, respectively. Thereafter, visual analog scale score continuously declined, falling to 0.1 (95% CI, 0.0 to 0.2) and 0.2 (95% CI, 0.0 to 0.3) in the 2 respective groups by 1 hour following conclusion of the treatment period. There was no statistically significant difference between the groups in the treatment profile of visual analog scale scores (p = 0.701). Significant posttreatment improvements were demonstrated in International Prostate Symptom Score, peak flow rate, post-void residual urine and quality of life scores but there were no significant differences between the groups in the magnitude of improvement in these outcome measures.

CONCLUSIONS

High energy transurethral microwave thermotherapy is well tolerated by patients under topical anesthesia alone and, therefore, can be administered in the outpatient setting without potent medications that necessitate intensive patient monitoring, pose risks for side effects and add to treatment costs.

Tolerability of high energy transurethral microwave thermotherapy with topical urethral anesthesia: results of a prospective, randomized, single-blinded clinical trial

PURPOSE

We determine the tolerability of high energy transurethral microwave thermotherapy with topical urethral anesthesia alone without supplementary systemic sedoanalgesia.

MATERIALS AND METHODS

A total of 45 patients with symptomatic benign prostatic hyperplasia were randomized to high energy transurethral microwave thermotherapy using either topical urethral anesthesia alone (topical anesthesia group) or topical anesthesia with adjunctive intravenous sedoanalgesia (sedoanalgesia group). Pain was evaluated sequentially by means of a 0 to 10 visual analog scale score. Posttreatment followup included determinations of International Prostate Symptom Score, peak flow rate, post-void residual urine, and quality of life score at 6 and 12 weeks.

RESULTS

Upon commencement of microwave treatment mean visual analog scale score was 1.3 (95% confidence interval [CI], 1.0 to 1.7) in the sedoanalgesia group and 1.4 (95% CI, 1.0 to 1.9) in the topical anesthesia group. During therapy visual analog scale score increased to a peak at 30 minutes of 2.0 (95% CI, 1.6 to 2.4) and 2.2 (95% CI, 1.7 to 2.6) in the sedoanalgesia and topical anesthesia groups, respectively. Thereafter, visual analog scale score continuously declined, falling to 0.1 (95% CI, 0.0 to 0.2) and 0.2 (95% CI, 0.0 to 0.3) in the 2 respective groups by 1 hour following conclusion of the treatment period. There was no statistically significant difference between the groups in the treatment profile of visual analog scale scores (p = 0.701). Significant posttreatment improvements were demonstrated in International Prostate Symptom Score, peak flow rate, post-void residual urine and quality of life scores but there were no significant differences between the groups in the magnitude of improvement in these outcome measures.

CONCLUSIONS

High energy transurethral microwave thermotherapy is well tolerated by patients under topical anesthesia alone and, therefore, can be administered in the outpatient setting without potent medications that necessitate intensive patient monitoring, pose risks for side effects and add to treatment costs.

Contrasting heating patterns and efficiency of the Prostatron and Targis microwave antennae for thermal treatment of benign prostatic hyperplasia

OBJECTIVES

To determine the design and performance characteristics of two microwave antennae for use in thermal treatment of benign prostatic hyperplasia.

METHODS

Prostatron and Targis antennae were subjected to detailed physical examination and measurement. The heating patterns generated by these two types of antennae were characterized in detail using tissue-equivalent phantoms. Measurements of return loss as a function of frequency were conducted to evaluate the capacity of the antennae for impedance matching. Percent reflected power was calculated from the return loss results to provide a relative measure of potential for efficient delivery of thermal energy.

RESULTS

The Prostatron antenna was found to be a monopole design consisting of a coaxial cable with a 3.3-cm length of inner conductor exposed at the tip. The Targis antenna was observed to be a dipole design with a 2.8-cm helical coil attached through a ground connection and a tap point to a coaxial cable. The heating pattern of the Targis antenna was symmetric; that of the Prostatron was asymmetric with substantial back heating along the catheter axis in the direction of the microwave power source. The mean extension of the 30 degrees C isotherm in the direction of the power source with the Prostatron antenna (71.5 mm; 95% confidence interval [CI], 63.4 to 79.6 mm) was 55% greater (P < 0.0005) than that with the Targis antenna (46.0 mm; 95% CI, 38.2 to 53.8 mm). Return loss with the Targis antenna declined sharply to a relative minimum value of -32.9 dB (95% CI, -73.8 to 8.0 dB) at 915 MHz, providing evidence of this antenna's capacity for impedance matching; little change was observed with the Prostatron in return loss over a frequency range 100 MHz above and below this antenna's standard operating frequency of 1296 MHz. The mean reflected power of the Targis antenna (0.4%; 95% CI, 0.0% to 1.4%) was lower by more than 20-fold (P = 0.036) than that of the Prostatron antenna (11.0%; 95% CI, 3.4% to 18.7%); thus, the potential for efficient operation was greater with the Targis than the Prostatron antenna.

CONCLUSIONS

The Targis microwave antenna was found to provide a more targeted heating pattern and have a capacity for more efficient thermal energy delivery than the Prostatron antenna. These differences observed in vitro could potentially translate into clinical advantages in vivo, such as improved tolerability of microwave treatment, reduced risk of complications, greater thermoablative efficacy, and scalability.

A high-efficiency microwave thermoablation system for the treatment of benign prostatic hyperplasia: results of a randomized, sham-controlled, prospective, double-blind, multicenter clinical trial

OBJECTIVES

To determine the effectiveness, safety, and impact on patient quality of life (QOL) of a novel transurethral microwave thermoablation system for the treatment of benign prostatic hyperplasia (BPH).

METHODS

A total of 169 patients with BPH were randomized to undergo a 1-hour microwave (n = 125) or sham (n = 44) procedure using the Urologix Targis thermoablation system on an outpatient basis, without general or regional anesthesia. Symptoms, flow rates, and QOL scores were determined before the study procedure and periodically thereafter up to 6 months.

RESULTS

Mean American Urological Association (AUA) score in the microwave group diminished 50% (P <0.0005) by the 6-month evaluation (10.5, 95% confidence interval [CI] 9.2 to 11.8) compared with baseline values (20.8, 95% CI 19.8 to 21.9). The sham group also exhibited lower postprocedural AUA scores; however, the magnitude of the postprocedural decline in AUA score in the microwave group was significantly greater (P <0.01) than that in the sham group. Half the microwave group had an AUA score of less than 9 by 6 months, and the decrease in symptoms was similar among patients with initially moderate versus initially severe symptoms. Mean peak urinary flow rate (Qmax) in the microwave group increased 51% (P <0.0005) by 6 months to 11.8 mL/s (95% CI 10.7 to 13.0) versus a pretreatment value of 7.8 mL/s (95% CI 7.4 to 8.2). The magnitude of the postprocedural increase in Qmax was significantly greater in the microwave than the sham group (P <0.05). In nearly half the microwave group (47%), Qmax increased 50% or more by 6 months compared with 24% of the sham group. Microwave treatment resulted in a significantly greater (P <0.05) positive impact on patient QOL than did the sham procedure. By 6 months, the QOL score in microwave-treated patients (2.2, 95% CI 1.9 to 2.4) averaged 48% lower (P <0.0005) than that at baseline (4.2, 95% CI 4.0 to 4.4). Significantly greater durability of treatment effects was also evident with microwave than with sham treatment, as judged by the higher proportion of microwave-treated patients (98.4%) requiring no further treatment during the 6-month study period versus 83.3% of sham control patients (P <0.0005). Microwave treatment was well tolerated, and complications were generally minor, readily manageable, and transitory.

CONCLUSIONS

The microwave thermoablation system proved to be an effective and safe treatment modality for BPH, with a positive impact on patient QOL.