Predictors of treatment outcome for high-energy transurethral microwave thermotherapy

Transurethral microwave thermotherapy effectiveness in small prostates

OBJECTIVES

To dispel the misconceptions that patients with small prostates react differently than patients with larger prostates to cooled transurethral microwave thermotherapy. Cooled transurethral microwave thermotherapy has developed into a valid alternative to treat men with lower urinary tract symptoms due to benign prostatic hyperplasia. However, doubts still remain regarding the ability of this office-based technique to treat smaller prostates.

METHODS

A database of 713 men from six previous studies using cooled transurethral microwave thermotherapy devices developed by Urologix were combined for this analysis. The data were analyzed to determine whether the baseline prostate size had a significant effect on American Urological Association Symptom Index, peak flow rate, quality-of-life score, or symptom problem index. Follow-up intervals in this analysis include 6, 12, 24, 36, 48, and 60 months after therapy. Visual analog scale ratings during treatment were also assessed. General linear models and repeated measures analyses were performed.

RESULTS

Statistical analysis showed no effect of baseline prostate size on treatment outcomes for more than 5 years. Visual analog scale measurements were also not affected by the baseline prostate size.

CONCLUSIONS

Transurethral microwave thermotherapy appears to be as efficacious in treating patients with small prostates as those with large prostates and should be offered as a treatment modality to patients with prostates of all sizes.

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.

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.

High-energy transurethral microwave thermotherapy: symptomatic vs urodynamic success

OBJECTIVE

To evaluate the subjective and objective treatment results of high-energy transurethral microwave thermotherapy (TUMT) for symptomatic benign prostatic hyperplasia (BPH), and investigate the possible variables for predicting symptomatic and/or urodynamic success.

PATIENTS AND METHODS

Between October 1998 and October 2000, 40 men with BPH underwent high-energy TUMT using the Targis device (Urologix, Inc., Minneapolis, MN, USA). Evaluation after treatment included a clinical determination of the symptom score, a urodynamic assessment by peak flow rate and pressure-flow, magnetic resonance imaging (MRI), transrectal ultrasonography and endoscopy. The objective and subjective success was correlated with several variables before, during and after treatment.

RESULTS

All patients completed at least 1 year of follow-up after TUMT as monotherapy. The symptom score improved from a median (range) of 20.5 (11-28) initially to 9 (0-28) (P < 0.001). Twenty-two patients (55%) had a marked and 11 (28%) a moderate response, giving an overall subjective success rate of 83%. Similarly, there was a significant improvement in peak flow rate, from 9.2 (4.4-13.4) to 15 (3.3-22.9) mL/s (P < 0.001). Twenty-one patients (53%) had a maximum flow rate of > 15 mL/s while in eight (20%) it was 10-15 mL/s. Only 20 patients changed from unobstructed on the pressure-flow nomogram, i.e. an overall objective success rate of 50%. Gadolinium-enhanced T1-weighted MRI 1 week after treatment showed a median (range) perfusion defect of 20.7 (5.5-76.6)% of the total gland volume. Despite this persisting in all patients, a well-defined cavity was apparent in only in seven (18%) at the final evaluation. Cystoscopy 1 month after therapy showed evidence of necrotic tissue occupying the prostatic fossa in all patients. Younger patients were more likely to be urodynamically successful, and a higher grade of obstruction predicted symptomatic success.

CONCLUSION

High-energy TUMT can induce considerable necrosis of the prostate, as shown by MRI and cystoscopy. Although there was an adequate improvement in most patients' symptoms, there was a successful urodynamic change to unobstructed in only half the patients. Younger patients and those with a higher grade of obstruction were more likely to have urodynamic and symptomatic success, respectively.

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.

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.

Transurethral microwave thermotherapy: first experiences in Poland

OBJECTIVE

To present early experiences in Poland with high-energy transurethral microwave thermotherapy (HeTUMT), considered as a serious alternative to surgery in managing benign prostatic hypertrophy (BPH).

PATIENTS AND METHODS

Sixty-one patients were treated in two centres using a commercial TUMT system. The patients were assessed at 5-6 weeks, 3 and 6 months after treatment, evaluating subjective complaints, the International Prostate Symptom Score (IPSS), urinary flow rate and postvoid residual volume.

RESULTS

A complete follow-up was available in 44 patients; most had symptomatic improvement 3 months after HeTUMT but it was slightly less pronounced after 6 months. The improvement in objective variables increased up to 6 months after HeTUMT. There was > or = 50% improvement in subjective complaints in 43% of the patients, in urinary flow rate in 25% and in residual urine in half. Two patients required re-treatment for a urethral stricture and ineffective HeTUMT.

CONCLUSIONS

HeTUMT may be a useful treatment for BPH but the outcome for an individual patient seems to be unpredictable. The indications for TUMT should be reviewed individually for each patient.

Mediating transurethral microwave thermotherapy by intraprostatic and periprostatic injections of mepivacaine epinephrine: effects on treatment time, energy consumption, and patient comfort

BACKGROUND AND PURPOSE

Profound intraprostatic blood flow may complicate reaching a therapeutic temperature in the prostate during transurethral microwave thermotherapy (TUMT) for benign prostatic hyperplasia (BPH). A retrospective survey is presented describing the effect of intraprostatic and periprostatic administration of mepivacaine epinephrine on treatment time, intraprostatic blood flow, energy delivery, and patient comfort.

PATIENTS AND METHODS

Fifteen consecutive obstructed patients with lower urinary tract symptoms attributable to BPH received TUMT (ProstaLund Feedback Treatment). In order to improve patient comfort, injections of 10 mL of 0.5% mepivacaine epinephrine were administered in three locations into the prostate prior to treatment. The results were compared with those of a reference group consisting of 35 consecutive patients who had received ProstaLund Feedback Treatment without administration of mepivacaine epinephrine.

RESULTS

Patients who received intraprostatic mepivacaine epinephrine had a shorter treatment time (32+/-9 minutes v 61+/-6 minutes), required less energy (65+/-27 kJ v 172+/-32 kJ), and had a lower calculated intraprostatic blood flow (13+/-5 units/minute v 26+/-12 units/minute) than the reference group. Patients receiving mepivacaine epinephrine also required less analgesic medication during the treatment. The clinical outcome in terms of symptom scores and peak uroflow rates appeared to be similar for the two groups.

CONCLUSION

Intraprostatic injection of mepivacaine epinephrine prior to TUMT seems to have beneficial effects. It may represent an important improvement of thermotherapy and enable successful treatment of those patients who previously failed secondary to a profound intraprostatic blood flow.

Morphological and biological predictors for treatment outcome of transurethral microwave thermotherapy

The proliferation of prostatic tissue as a result of ageing typically leads to prostatic enlargement, which often causes obstruction of urine outflow from the bladder, clinically lower urinary tract symptoms, detrusor instability, incomplete bladder emptying, urinary infection, and finally acute urinary retention. The first approach to therapy depending on the severity of the symptoms is usually medical management (phytotherapy, alpha-blockers, 5 alpha-reductase inhibitors) before surgical procedures are performed. The reference standard for treatment of benign prostatic hyperplasia is transurethral resection of the prostate, although the introduction of minimally invasive alternatives such as transurethral microwave thermotherapy has led to a new era in surgical management. Suitable patients must be selected carefully on the basis of individual parameters that predict a favourable result.