Transurethral microwave thermotherapy: how does it work?

Therapeutic efficacy of bipolar radiofrequency thermotherapy for patients with chronic prostatitis: a retrospective analysis of 26 cases

PURPOSE

Chronic prostatitis (CP) does not yet have a universally successful therapy. Alternative treatments including thermotherapy have been adopted in the multimodal management of pain and voiding dysfunction. We retrospectively analyzed the therapeutic efficacy of bipolar radiofrequency thermotherapy for patients who were unsatisfied with conventional medication for CP.

MATERIALS AND METHODS

A retrospective study between October 2009 and September 2010 of 26 patients who were under 50 years old and diagnosed with CP (National Institutes of Health [NIH]-category III) was performed. Twenty patients were diagnosed with inflammatory CP (NIH-category IIIa) and the rest with noninflammatory CP (NIH-category IIIb). We used the Tempro system at an intraprostatic temperature of 55℃ for 50 minutes with a medium heating rate. All patients also completed the NIH-Chronic Prostatitis Symptom Index (CPSI) before and after treatment.

RESULTS

In the patients diagnosed with CP, the mean serum prostate-specific antigen (PSA) level was 0.9±0.3 ng/ml, the prostate volume was 27.1±5.5 g, and the average score for all 3 domains on the NIH-CPSI significantly decreased. The total scores decreased from 19.8±7.1 to 11.1±7.0, the pain domain decreased from 8.6±3.1 to 4.8±3.1, the voiding symptom domain decreased from 5.1±1.8 to 2.9±1.8, and the effect on the quality of life decreased from 6.1±2.2 to 3.4±2.2 (p<0.05).

CONCLUSIONS

Bipolar radiofrequency thermotherapy for patients with CP intractable to conventional medication can provide significant improvement in the NIH-CPSI. Large, randomized controlled trials will also be required to confirm the efficacy of this therapy.

Transurethral microwave thermotherapy for the treatment of BPH: still a challenger?

Minimally invasive therapies for treatment of benign prostatic hyperplasia (BPH) compete with the gold standard transurethral resection of the prostate (TURP). Comparisons of efficacy and safety have broadened the knowledge of different treatment modalities. Concerns of quality of life such as unaltered sexual function as well as cost considerations drive the market to develop techniques of lower level invasiveness. Among the competitors the office based transurethral microwave thermotherapy (TUMT) provides the broadest scale of scientific data. Numerous manufacturers sell various modifications of this technology. According to different clinical studies TUMT proved to be an effective, safe, and durable therapy for the treatment of lower urinary tract symptoms (LUTS) secondary to BPH. However, TURP still holds the steadier long-term results and is more effective to reduce obstruction as well as other LUTS.

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.

Long-term treatment outcomes of CoreTherm microwave feedback thermotherapy

The gold standard for definitive management of symptomatic benign prostatic hypertrophy is transurethral resection of the prostate (TURP). Despite its efficacy, TURP has significant morbidity/mortality concerns such as hemorrhage and transurethral resection syndrome. This is especially worrisome for the medically high-risk patient, but the high rates of retrograde ejaculation found with TURP also pose a problem for young patients. A minimally invasive, outpatient alternative to TURP that has long-term efficacy, low morbidity/mortality, and provides a cost-effective advantage is in high demand. This review article discusses microwave thermotherapy as such an option and reports the long-term experience with the CoreTherm (CoreTherm Operations AB, Sweden) device.

Gadolinium-enhanced MRI in the evaluation of minimally invasive treatments of the prostate: correlation with histopathologic findings

OBJECTIVES

To explore the use of magnetic resonance imaging (MRI) with gadolinium enhancement as a noninvasive method to image the extent of ablation after minimally invasive treatment. Minimally invasive methods for ablating prostatic tissue have emerged as a viable option in the treatment of prostate disease. As these devices enter the mainstream of patient care, imaging methods that verify the exact location, extent, and pattern of the ablation are needed.

METHODS

Nineteen patients with prostate cancer were evaluated. All received some type of minimally invasive treatment, post-treatment gadolinium-enhanced MRI sequences, and radical retropubic prostatectomy for histopathologic evaluation. Visual comparisons of gadolinium defects and areas of coagulation necrosis as seen on histopathologic evaluation were made by us. Volumetric and two-dimensional area measurements of the ablation lesions were also compared for correlation between the MRI and histopathologic results.

RESULTS

Gadolinium-enhanced MRI could be matched to histopathologic findings by visual comparison in 17 of the 19 cases. Surgically distorted histopathologic specimens and a small periurethral lesion caused 2 patients to have MRI and histopathologic results that could not be matched. Complete volumetric measurements were available for 16 of the 19 patients and correlated strongly (r = 0.924). The two-dimensional area data for all patients also showed significant correlation (r = 0.886).

CONCLUSIONS

Correlation with histopathologic findings showed gadolinium-enhanced MRI to be useful for determining the location, pattern, and extent of necrosis caused within the prostate by minimally invasive techniques. Gadolinium-enhanced MRI gives the urologist a useful tool to evaluate the effectiveness of new minimally invasive therapies.

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.

Efficacy and safety of intraprostatic temperature-controlled microwave thermotherapy in patients with benign prostatic hyperplasia: results of a prospective, open-label, single-center study with 1-year follow-up

BACKGROUND AND PURPOSE

Different devices for transurethral microwave thermotherapy (TUMT) are currently available for the treatment of benign prostatic hyperplasia (BPH). We evaluated the efficacy and safety of the Prostalund Feedback Treatment (PLFT), which continuously records the intraprostatic temperature, and its impact on sexual function of the patients.

PATIENTS AND METHODS

A total of 41 patients with lower urinary tract symptoms attributed to BPH were entered in this prospective open-label, single-center study of PLFT. The initial evaluation was performed according to a standard protocol. At 3, 6, and 12 months, the International Prostate Symptom Score (IPSS), bother score, sexual function, and peak flow rate (Qmax) were recorded. In addition, determination of prostate volume by transrectal ultrasonography (TRUS) and measurement of residual urine volume were repeated at the 6- and 12-month visits. All adverse events were also recorded. Patients with IPSS of < or =7, > or =50% improvement in IPSS from baseline, a Qmax of > or =15 mL/sec, or > or =50% improvement in Qmax from baseline were judged responders to the treatment.

RESULTS

Thirty-three of the patients completed the 12-month visit. The response rate was 88% (29 of 33 patients). There was a statistically significant decrease in IPSS at the 12-month visit, the mean IPSS being 7.1 v 21.9 at baseline (P<0.001). The mean IPSS was 10.3 and 7.6 at the 3- and 6-months' follow-up, respectively. The bother score presented a similar improvement, with a decrease from a mean of 4.2 at baseline to a mean of 1.4 after 12 months (P<0.001). The mean Qmax improved from 8.4 mL/sec at baseline to 15.9 mL/sec, 19.2 mL/sec, and 17.8 mL/sec at 3, 6, and 12 months, respectively (P<0.001). The mean change in prostate volume, as determined by TRUS, was 16 mL at 6 months and 19 mL at 12 months (P<0.001). The procedure was well tolerated. The mean post-treatment catheterization time was 17.90 days. Bladder spasms and urinary tract infection were the most common adverse events. Coitus ability remained practically unchanged after treatment (from 71% to 74.3%), but the number of patients with ejaculation decreased (from 78% to 51.4%).

CONCLUSION

Our results indicate that PLFT is an effective and safe treatment for most patients with BPH.

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.

Feedback microwave thermotherapy versus TURP for clinical BPH--a randomized controlled multicenter study

OBJECTIVES

To compare the outcome of a microwave thermotherapy feedback system that is based on intraprostatic temperature measurement during treatment (ProstaLund Feedback Treatment or PLFT) with transurethral resection of the prostate (TURP) for clinical benign prostatic hyperplasia (BPH) in a randomized controlled multicenter study. The safety of the two methods was also investigated.

METHODS

The study was performed at 10 centers in Scandinavia and the United States. A total of 154 patients with clinical BPH were randomized to PLFT or TURP (ratio 2:1); 133 of them completed the study and were evaluated at the end of the study 12 months after treatment. Outcome measures included the International Prostate Symptom Score (IPSS), urinary flow, detrusor pressure at maximal urinary flow (Qmax), prostate volume, and adverse events. Patients were seen at 3, 6, and 12 months. Responders were defined according to a combination of IPSS and Qmax: IPSS 7 or less, or a minimal 50% gain, and/or Qmax 15 mL/s or greater or a minimal 50% gain.

RESULTS

No significant differences in outcome at 12 months were found between PLFT and TURP for IPSS, Qmax, or detrusor pressure. The prostate volume measured with transrectal ultrasonography was reduced by 30% after PLFT and 51% after TURP. Serious adverse events related to the given treatment were reported in 2% after PLFT and in 17% after TURP. Mild and moderate adverse events were more common in the PLFT group. With the criteria mentioned above, 82% and 86% of the patients were characterized as responders after 12 months in the PLFT and TURP groups, respectively. The post-treatment catheter time was 3 days in the TURP group and 14 days in the PLFT group.

CONCLUSIONS

The outcome of microwave thermotherapy with intraprostatic temperature monitoring was comparable with that seen after TURP in this study. From both a simplicity and safety point of view, PLFT appears to have an advantage. Taken together, our findings make us conclude that within a 1-year perspective microwave thermotherapy with PLFT is an attractive alternative to TURP in the treatment of BPH.