Transrectal high-intensity focused ultrasound for treatment of localized prostate cancer

Salvage external beam radiotherapy after HIFU failure in localized prostate cancer: A single institution experience

Purpose/objectives

High-intensity focused ultrasound (HIFU) remains investigational as primary treatment for localized prostate cancer but is sometimes offered to select patients. At HIFU failure, data guiding salvage treatment is limited to small retrospective series with short follow-up. We evaluated our institutional experience using salvage radiation therapy (SRT) after HIFU failure.

Materials/methods

We conducted a retrospective analysis of patients with local failure post-HIFU who received salvage image-guided external beam radiation therapy (EBRT) delivered via intensity-modulated radiotherapy (IMRT). Our primary endpoint was biochemical failure-free survival (bFFS) defined as prostate-specific antigen (PSA) nadir + 2 ng/mL. Secondary endpoints included metastasis-free survival (MFS) and overall survival (OS). Endpoints were evaluated using Kaplan-Meier analysis.

Results

From 2013 to 2018, 12 out of 96 patients treated with primary HIFU received SRT via conventional or moderate hypofractionation. Median time from HIFU to SRT was 13.5 months. Seven patients had stage migration to high-risk disease at the time of SRT. Mean PSA prior to SRT was 8.2ug/L and mean nadir post-SRT was 1.2ug/L. Acute International Prostate Symptom Score (IPSS) as well as International Index of Erectile Dysfunction (IIEF) scores were similar to baseline (p = 0.5 and 0.1, respectively). Late toxicities were comparable to those reported after primary EBRT for localized prostate cancer. At a median follow-up of 46 months, the OS was 100%. The 5-year bFFS and MFS were both 83.3%.

Conclusions

To our knowledge, we report one of the largest series on contemporary SRT post HIFU failure. We show that SRT is feasible, effective and carries no additional acute or delayed toxicity.

Whole-gland high-intensity focused ultrasound ablation and transurethral resection of the prostate in the patients with prostate cancer: A systematic review and meta-analysis

Background

We aimed to conduct a systematic review and meta-analysis of studies reporting functional and oncologic outcomes of combining whole-gland high-intensity focused ultrasound ablation (HIFU) with transurethral resection of the prostate (TURP) in prostate cancer (PCa) patients.

Methods

PubMed, Embase, Web of Science, Scopus, and Cochrane Library were systematically searched until June 30, 2022. The ROBINS-I tool scale was used to evaluate quality of eligible studies. Biochemical failure was defined according to the criteria used in each raw study. The presence of any cancer on follow-up biopsy was classified as “positive biopsy”. Patients able to penetrate their partner without pharmacologic support were rated potent. Meta-analysis was performed to evaluate functional outcomes using R project.

Results

A total of 1861 patients in 15 eligible studies were included. All studies were identified as moderate or high quality. There were 1388 (74.6%) patients with low-risk or intermediate-risk PCa in 15 studies and 473 (25.4%) patients with high-risk PCa in 12 studies. The mean PSA nadir postoperatively ranged from 0.20 to 1.90 ng/mL within average time of 1.9-12 months. Biochemical failure rates in all 15 studies ranged from 6.3% to 34% within average time of 1.9-60 months. Eleven studies reported the rates of positive biopsy ranged from 3% to 29.7% within average time of 3-12 months postoperatively. Based on the results of single-arm meta-analysis, the pooled rates of any degree urinary incontinence, acute urinary retention, urinary tract infections, and urethral stricture were 9.4% (95% CI: 6.1%-12.6%), 0.9% (95% CI: 0%-2%), 2.6% (95% CI: 0.8%-4.3%), and 4.3% (95% CI: 1.4%-7.1%), respectively. The pooled rate of being potent after procedure in previously potent patients was 43.6% (95% CI: 27.3%-59.8%). The sensitivity analysis revealed all the pooled results was relatively reliable. Egger’s tests for the pooled results of acute urinary retention (p = 0.0651) and potency (p = 0.6749) both did not show significant publication bias.

Conclusions

It appears that the combination treatment of whole-gland HIFU and TURP could be applied for PCa patients. It might have potential advantages of decreasing catheterization time and improving urinary status. Prospective and comparative studies are needed to validate our findings.

Feasibility of magnetic resonance imaging-ultrasound guided high-dose-rate brachytherapy for localized prostate cancer: Preliminary results from a prospective study

OBJECTIVE

This study aimed to investigate preliminary outcomes of a prospective trial of magnetic resonance imaging-ultrasound fusion-guided ultrafocal high-dose-rate brachytherapy in localized prostate cancer.

METHODS

In our prospective study, data from patients who underwent this treatment between April 1, 2020 and March 31, 2021 were analyzed. In the procedure, the applicator needle was inserted through the perineum to target the lesion on the multiparametric magnetic resonance imaging, which was fused onto the transrectal ultrasound image. The prescription dose was set at a single fraction of 19 Gy. Data from patients who received whole-gland high-dose-rate brachytherapy were extracted and compared with data from patients who received ultrafocal high-dose-rate brachytherapy, to evaluate the frequency of acute adverse events.

RESULTS

Eight patients underwent ultrafocal high-dose-rate brachytherapy with a median observation period of 7.75 months (range 5.96-15.36 months). No acute genitourinary or gastrointestinal adverse events were observed in this cohort. The planned procedure was completed in all patients, and no unexpected adverse events were observed; however, prostate-specific antigen failure was detected in one patient. In the 25 patients who underwent whole-gland high-dose-rate brachytherapy, acute genitourinary and gastrointestinal adverse events were observed in 88% and 20% of the patients, respectively. Ultrafocal high-dose-rate brachytherapy was a significant factor in avoiding acute adverse genitourinary events in univariate and multivariate analyses (P < 0.001 and P = 0.032, respectively).

CONCLUSIONS

Magnetic resonance imaging-ultrasound fusion-guided ultrafocal high-dose-rate brachytherapy in localized prostate cancer is a safe and feasible treatment without acute genitourinary and gastrointestinal adverse events. Long-term observation and further investigation are warranted.

Clinical application of the therapeutic ultrasound in urologic disease: Part II of the therapeutic ultrasound in urology

This article aimed to review the clinical application and evidence of the therapeutic ultrasound in detail for urological diseases such as prostate cancer, kidney tumor, erectile dysfunction, and urolithiasis. We searched for articles about high-intensity focused ultrasound (HIFU), extracorporeal shock wave therapy, ultrasound lithotripsy, and extracorporeal shockwave lithotripsy (ESWL) in the MEDLINE and Embase. HIFU may be indicated as a primary treatment for low- or intermediate-risk prostate cancer, and salvage therapy for local recurrence as a promising way to address the limitations of current standard therapies. The application of HIFU in treating kidney tumors has scarcely been reported with unsatisfactory results. Evidence indicates that low-intensity shockwave therapy improves subjective and objective erectile function in patients with erectile dysfunction. Regarding the application of ultrasound in stone management, the novel combination of ultrasound lithotripsy and other energy sources in a single probe promises to be a game-changer in efficiently disintegrating large kidney stones in percutaneous nephrolithotomy. ESWL is losing its role in managing upper urinary tract calculi worldwide. The burst-wave lithotripsy and ultrasound propulsion could be the new hope to regain its position in the lithotripsy field. According to our investigations and reviews, cavitation bubbles of the therapeutic ultrasound are actively being used in the field of urology. Although clinical evidence has been accumulated in urological diseases such as prostate cancer, kidney tumor, erectile dysfunction, and lithotripsy, further development is needed to be a game-changer in treating these diseases.

The primary treatment of prostate cancer with high-intensity focused ultrasound: A systematic review and meta-analysis

BACKGROUND

We systematically evaluated the evidences on oncological and functional outcomes of high-intensity focused ultrasound (HIFU) as the primary treatment for localized prostate cancer (PCa).

METHODS

A systematic review was used Medline, Embase, and the Cochrane Library from the inception of each database. The review analyzed the oncological and functional outcomes of HIFU in the treatment of PCa. The RevMan 5.3 software was used for quantity analysis incidence of complications.

RESULTS

Twenty-seven articles were included for analysis with a total of 7393 patients. Eighteen studies investigated the whole-gland HIFU, and the duration of follow-up ranged from 2 to 168 months. After whole-gland HIFU, the mean prostate-specific antigen (PSA) nadir was found to be 0.4 to 1.95 ng/mL and the mean time to PSA nadir was 2.4 to 5.4 months. The rate of positive biopsy after HIFU was 4.5% to 91.1%. Meta-analysis revealed the incidences of urinary incontinence, impotence, urinary obstruction, retention, and infection was 10%, 44%, 15%, 11%, 7%, respectively. Nine studies investigated partial-gland HIFU, and the duration of follow-up was 1 to 131 months. After partial-gland HIFU, the mean PSA nadir was 1.9 to 2.7 ng/mL and the mean time to PSA nadir 5.7 to 7.3 months. The rate of positive biopsy after HIFU in the treatment area was 14% to 37.5%. Meta-analysis revealed the incidences of urinary incontinence, impotence, urinary obstruction, retention, and infection was 2%, 21%, 2%, 9%, 11%, respectively.

CONCLUSIONS

Early evidence suggested the partial-gland HIFU was safer than whole-gland HIFU, and they had similar oncological outcomes. More prospective randomized controlled trials of whole-gland and partial-gland HIFU for PCa was needed.

Equivalence of cell survival data for radiation dose and thermal dose in ablative treatments: analysis applied to essential tremor thalamotomy by focused ultrasound and gamma knife

Thermal dose and absorbed radiation dose have historically been difficult to compare because different biological mechanisms are at work. Thermal dose denatures proteins and the radiation dose causes DNA damage in order to achieve ablation. The purpose of this paper is to use the proportion of cell survival as a potential common unit by which to measure the biological effect of each procedure. Survival curves for both thermal and radiation doses have been extracted from previously published data for three different cell types. Fits of these curves were used to convert both thermal and radiation dose into the same quantified biological effect: fraction of surviving cells. They have also been used to generate and compare survival profiles from the only indication for which clinical data are available for both focused ultrasound (FUS) thermal ablation and radiation ablation: essential tremor thalamotomy. All cell types could be fitted with coefficients of determination greater than 0.992. As an illustration, survival profiles of clinical thalamotomies performed by radiosurgery and FUS are plotted on a same graph for the same metric: fraction of surviving cells. FUS and Gamma Knife have the potential to be used in combination to deliver a more effective treatment (for example, FUS may be used to debulk the main tumour mass, and radiation to treat the surrounding tumour bed). In this case, a model which compares thermal and radiation treatments is valuable in order to adjust the dose between the two.

Ablative therapy for people with localised prostate cancer: a systematic review and economic evaluation

BACKGROUND

For people with localised prostate cancer, active treatments are effective but have significant side effects. Minimally invasive treatments that destroy (or ablate) either the entire gland or the part of the prostate with cancer may be as effective and cause less side effects at an acceptable cost. Such therapies include cryotherapy, high-intensity focused ultrasound (HIFU) and brachytherapy, among others.

OBJECTIVES

This study aimed to determine the relative clinical effectiveness and cost-effectiveness of ablative therapies compared with radical prostatectomy (RP), external beam radiotherapy (EBRT) and active surveillance (AS) for primary treatment of localised prostate cancer, and compared with RP for salvage treatment of localised prostate cancer which has recurred after initial treatment with EBRT.

DATA SOURCES

MEDLINE (1946 to March week 3, 2013), MEDLINE In-Process & Other Non-Indexed Citations (29 March 2013), EMBASE (1974 to week 13, 2013), Bioscience Information Service (BIOSIS) (1956 to 1 April 2013), Science Citation Index (1970 to 1 April 2013), Cochrane Central Register of Controlled Trials (CENTRAL) (issue 3, 2013), Cochrane Database of Systematic Reviews (CDSR) (issue 3, 2013), Database of Abstracts of Reviews of Effects (DARE) (inception to March 2013) and Health Technology Assessment (HTA) (inception to March 2013) databases were searched. Costs were obtained from NHS sources.

REVIEW METHODS

Evidence was drawn from randomised controlled trials (RCTs) and non-RCTs, and from case series for the ablative procedures only, in people with localised prostate cancer. For primary therapy, the ablative therapies were cryotherapy, HIFU, brachytherapy and other ablative therapies. The comparators were AS, RP and EBRT. For salvage therapy, the ablative therapies were cryotherapy and HIFU. The comparator was RP. Outcomes were cancer related, adverse effects (functional and procedural) and quality of life. Two reviewers extracted data and carried out quality assessment. Meta-analysis used a Bayesian indirect mixed-treatment comparison. Data were incorporated into an individual simulation Markov model to estimate cost-effectiveness.

RESULTS

The searches identified 121 studies for inclusion in the review of patients undergoing primary treatment and nine studies for the review of salvage treatment. Cryotherapy [3995 patients; 14 case series, 1 RCT and 4 non-randomised comparative studies (NRCSs)], HIFU (4000 patients; 20 case series, 1 NRCS) and brachytherapy (26,129 patients; 2 RCTs, 38 NRCSs) studies provided limited data for meta-analyses. All studies were considered at high risk of bias. There was no robust evidence that mortality (4-year survival 93% for cryotherapy, 99% for HIFU, 91% for EBRT) or other cancer-specific outcomes differed between treatments. For functional and quality-of-life outcomes, the paucity of data prevented any definitive conclusions from being made, although data on incontinence rates and erectile dysfunction for all ablative procedures were generally numerically lower than for non-ablative procedures. The safety profiles were comparable with existing treatments. Studies reporting the use of focal cryotherapy suggested that incontinence rates may be better than for whole-gland treatment. Data on AS, salvage treatment and other ablative therapies were too limited. The cost-effectiveness analysis confirmed the uncertainty from the clinical review and that there is no technology which appears superior, on the basis of current evidence, in terms of average cost-effectiveness. The probabilistic sensitivity analyses suggest that a number of ablative techniques are worthy of further research.

LIMITATIONS

The main limitations were the quantity and quality of the data available on cancer-related outcomes and dysfunction.

CONCLUSIONS

The findings indicate that there is insufficient evidence to form any clear recommendations on the use of ablative therapies in order to influence current clinical practice. Research efforts in the use of ablative therapies in the management of prostate cancer should now be concentrated on the performance of RCTs and the generation of standardised outcomes.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002461.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Head phantoms for transcranial focused ultrasound

PURPOSE

In the ongoing endeavor of fine-tuning, the clinical application of transcranial MR-guided focused ultrasound (tcMRgFUS), ex-vivo studies wlkiith whole human skulls are of great use in improving the underlying technology guiding the accurate and precise thermal ablation of clinically relevant targets in the human skull. Described here are the designs, methods for fabrication, and notes on utility of three different ultrasound phantoms to be used for brain focused ultrasound research.

METHODS

Three different models of phantoms are developed and tested to be accurate, repeatable experimental options to provide means to further this research. The three models are a cadaver, a gel-filled skull, and a head mold containing a skull and filled with gel that mimics the brain and the skin. Each was positioned in a clinical tcMRgFUS system and sonicated at 1100 W (acoustic) for 12 s at different locations. Maximum temperature rise as measured by MR thermometry was recorded and compared against clinical data for a similar neurosurgical target. Results are presented as heating efficiency in units (°C/kW/s) for direct comparison to available clinical data. The procedure for casting thermal phantom material is presented. The utility of each phantom model is discussed in the context of various tcMRgFUS research areas.

RESULTS

The cadaveric phantom model, gel-filled skull model, and full head phantom model had heating efficiencies of 5.3, 4.0, and 3.9 °C/(kW/s), respectively, compared to a sample clinical heating efficiency of 2.6 °C/(kW/s). In the seven research categories considered, the cadaveric phantom model was the most versatile, though less practical compared to the ex-vivo skull-based phantoms.

CONCLUSIONS

Casting thermal phantom material was shown to be an effective way to prepare tissue-mimicking material for the phantoms presented. The phantom models presented are all useful in tcMRgFUS research, though some are better suited to a limited subset of applications depending on the researchers needs.

The Effects of Focal Therapy for Prostate Cancer on Sexual Function: A Combined Analysis of Three Prospective Trials

BACKGROUND

Tissue preservation by means of focal therapy offers some men with clinically significant prostate cancer an alternative to standard care that appears to confer favourable genito-urinary outcomes. The precise estimates of these outcomes have so far been based on small series.

OBJECTIVE

This analysis pools the sexual domain related patient reported outcomes from three prospective, registered studies that represent a range of inclusion criteria.

DESIGN, SETTING, AND PARTICIPANTS

One-hundred and eighteen men with localised prostate cancer (prostate specific antigen ≤ 15ng/ml, Gleason ≤ 4+3, stage ≤ T3aN0M0) treated in a tissue-preserving manner using high intensity focused ultrasound from three registered studies were included. Data on International Index of Erectile Function (IIEF-5) scores and use of phosphodiesterase-5-inhibitors were collected at baseline, and 1 mo, 3 mo, 6 mo, 9 mo, and 12 mo postoperatively. The IIEF-15 total and individual domain scores were used to assess overall sexual function. Urinary function was assessed with the International Prostate Symptom Score (IPSS), IPSS quality-of-life, and UCLA-Expanded Prostate Cancer Index Composite continence questionnaires. General health status was derived by means of the Charlson score. Multiple linear regression was used to assess whether age, grade, stage, qualitative scores (IIEF, IPSS, Expanded Prostate Cancer Index Composite, Charlson), or focal therapy type duration were associated with IIEF-5 and IIEF-15 scores at 12 mo.

RESULTS AND LIMITATIONS

Median age was 63 yr (interquartile range [IQR] 52-70 yr). Median IIEF-erectile score at baseline was 23 (IQR 11-28). This declined significantly to 9 (IQR 3-22, p<0.01) at 1 mo, but improved to 20 (IQR 9-29, p=0.30) at 1 yr posttreatment. Changes in total IIEF and other IIEF domains were only significantly different from preoperative values at 1 mo and 3 mo postoperatively. In the same period, the proportion of men using phosphodiesterase-5-inhibitors was 10% preoperatively, reaching 43% and 42% at 6 mo and 9 months before declining to 37% at 1 yr. The only baseline determinants of postoperative erectile function were total IIEF and IIEF-erectile function scores (p=0.002). The primary limitation of our study is the relatively short follow-up of 1 yr.

CONCLUSION

Men who received a range of tissue preserving therapies from the three pertinent studies experienced small decreases in total IIEF, erectile, and individual sexual domain scores that are not significantly different to those recorded at baseline. The only determinant of erectile dysfunction after tissue preserving therapy was preoperative erectile dysfunction status. Tissue preservation confers a high probability of maintaining erectile function that appears independent of all perioperative factors with the exception of baseline status.

PATIENT SUMMARY

In this report, the largest prospectively collected and published set of patients with erectile dysfunction outcomes post-focal therapy for prostate cancer, we have found a return to baseline International Index of Erectile Function-erectile and total International Index of Erectile Function scores by 6 mo post-focal therapy which was maintained at 1 yr, with the majority of patients not on any form of medical treatment for their erectile dysfunction at that point. Focal therapy may represent a suitable alternative for men of any age or comorbidity wishing to maintain erectile function.

Systematic Review of the Efficacy and Safety of High-intensity Focussed Ultrasound for Localised Prostate Cancer

CONTEXT

High-intensity focussed ultrasound (HIFU) has been used for 10 yr to treat localised prostate cancer (PCa).

OBJECTIVE

To evaluate systematically the evidence on the efficacy and side effects of HIFU in the primary treatment of localised PCa.

EVIDENCE ACQUISITION

We performed a critical review and appraisal of Medline (Ovid), PreMedline, Embase, and Cochrane Database of Systematic Reviews publications on HIFU up to May 2013. One systematic review and 18 primary studies, all case series, were eligible.

EVIDENCE SYNTHESIS

Outcomes were summarised and evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluation methodology. Low-quality evidence suggests an overall survival rate after Ablatherm HIFU ranging from 80% to 89% for >5 yr. The PCa survival rate ranges from 97% to 99% for >5 yr. Effect of HIFU on quality of life remains undetermined. Erectile dysfunction was the most frequent adverse event reported from zero but up to 74% of patients. Adverse events affecting the urinary tract occurred in 0.7-31% of patients, bladder outlet obstruction in 4-51.5%, and they were more frequent in patients who had transurethral resection of the prostate the same day or within 2 d of HIFU. Outcomes vary for low- and high-risk categories.

CONCLUSIONS

Good quality evidence on the efficacy of HIFU treatment for localised PCa is lacking.

PATIENT SUMMARY

We reviewed all the data on treatment with high-intensity focussed ultrasound (HIFU) for localised prostate cancer (PCa). The quality of the evidence is very low because the information is based on a series of patients who received HIFU treatment with no comparison with active surveillance or radical treatment. Case series suggest an overall survival rate up to 89% and a PCa survival rate up to 99% after 5 yr, but these numbers vary according to the patient's risk category. Longer term and effects on quality of life are unknown.

Surgical management of prostate cancer

Surgery remains a mainstay in the management of localized prostate cancer. This article addresses surgical aspects germane to the management of men with prostate cancer, including patient selection for surgery, nerve-sparing approaches, minimization of positive surgical margins, and indications for pelvic lymph node dissection. Outcomes for men with high-risk prostate cancer following surgery are reviewed, and the present role of neoadjuvant therapy before radical prostatectomy is discussed. In addition, there is a review of the published literature on surgical ablative therapies for prostate cancer.

Usefulness of proton magnetic resonance spectroscopy in predicting positive biopsy after high-intensity focused ultrasound for treatment of localized prostate cancer

OBJECTIVES

To investigate the clinical effectiveness of proton magnetic resonance spectroscopy in predicting local recurrence or residual disease after high-intensity focused ultrasound for treatment of localized prostate cancer.

METHODS

The present study included patients with localized prostate cancer who underwent high-intensity focused ultrasound of whole-gland ablation as primary therapy. Clinicopathological variables including proton magnetic resonance spectroscopy, T2-weighted magnetic resonance imaging, and prostate-specific antigen and its derivatives were analyzed to predict the positive prostate biopsy results using univariate and multivariate analyses. Furthermore, the presence of tumor in each of the 12 prostate sectors by T2-weighted magnetic resonance imaging and proton magnetic resonance spectroscopy were evaluated and compared with prostate biopsy results in each of the 12 prostate sectors in order to evaluate the local cancer distribution in the prostate after high-intensity focused ultrasound.

RESULTS

Overall, we carried out 85 prostate biopsies in 52 patients. Multivariate logistic regression analysis showed that the positive finding of proton magnetic resonance spectroscopy was the only statistically significant prognostic parameter of pathological tumor progression in patients after high-intensity focused ultrasound. Prostate biopsy cores were obtained from 952 prostate sectors of 52 patients and 85 prostate biopsies. Compared with T2-weighted magnetic resonance imaging, proton magnetic resonance spectroscopy (sensitivity 52.8%, specificity 97.4%, positive predictive value 44.2% and negative predictive value 98.1%, P < 0.001) has higher values to predict local tumor progression in prostate sectors after high-intensity focused ultrasound.

CONCLUSIONS

Proton magnetic resonance spectroscopy is a useful, non-invasive diagnostic modality that predicts local tumor progression in patients after high-intensity focused ultrasound, as well as local cancer distribution at each of the prostate sectors with pinpoint accuracy.

Transabdominal high-intensity focused ultrasound therapy of the prostate and determination of the protective effect of rectal cooling: an experimental study using canine prostates

OBJECTIVES

The purpose of this study was to report our initial experience with transabdominal high-intensity focused ultrasound (HIFU) therapy of the canine prostate and to determine the protective effect of rectal cooling during HIFU therapy.

METHODS

Fifteen male dogs underwent transabdominal HIFU therapy of the prostate. Transabdominal HIFU was performed on 9 dogs without using a rectal cooling device, and the remaining 6 dogs underwent transabdominal HIFU with introduction of the rectal cooling device. Magnetic resonance imaging (MRI) was performed before, immediately after, and 1 week after the HIFU procedure. Rectal changes on MRI were classified into 4 grades (grades 0-3), and a comparison of the rectal change grades on MRI between the two groups was performed with the Mann-Whitney U test.

RESULTS

The procedure failed for the first dog because of inadequate skin preparation. Of the remaining 14 dogs (8 without rectal cooling and 6 with rectal cooling), 4 showed focal signal changes in the prostate. The average rectal change grades on immediate postprocedural MRI were 2.63 for the non-rectal cooling group and 1.17 for the rectal cooling group (P = .0216). On 1-week follow-up MRI, the average grades were 1.20 for the non-rectal cooling group and 0.33 for the rectal cooling group (P = .1956).

CONCLUSIONS

Transabdominal HIFU of the canine prostate was technically feasible, but the effect was limited because of anatomic and physiologic factors of the canine prostate. The rectal cooling device seems to have a protective effect on the rectum during the transabdominal HIFU procedure.

Experimental studies and clinical experiences on treatment of secondary hypersplenism with extracorporeal high-intensity focused ultrasound

The aim of this study is to investigate the efficacy and safety of extracorporeal high-intensity focused ultrasound (HIFU) in treatment of hypersplenism. Fifteen adult dogs, weighing 13-18 kg were divided into three groups: sham group, SVL group undergoing splenic vein ligation (SVL) after laparotomy, and SVL + HIFU group receiving SVL followed by extracorporeal HIFU. Pathologic and hematologic analyses were performed. We also reviewed the clinical data of 19 patients with secondary hypersplenism caused by liver cirrhosis or hepatocellular carcinoma who underwent extracorporeal HIFU. Extracorporeal HIFU significantly diminished the volume of the spleen of animals, coupled with occurrence of coagulation necrosis and fibrosis in the target area. Both platelet and red blood cell counts were significantly restored by HIFU intervention. Similarly, HIFU treatment improved the hematologic parameters in patients with hypersplenism, and no major complications were encountered. Extracorporeal HIFU intervention is effective and safe in managing secondary hypersplenism.

The current role of high-intensity focused ultrasound for the management of radiation-recurrent prostate cancer

The standard treatment options for organ-confined prostate cancer are radical prostatectomy and radiation therapy. A number of minimally invasive new technologies have also recently emerged. High-intensity focused ultrasound (HIFU) is considered to be one of the most promising alternative therapies for prostate cancer. The indications for HIFU have recently been expanded to include its use both as a primary therapy for organ-confined prostate cancer as well as for local recurrence of prostate cancer, following radiation therapy. Although experience with the use of HIFU in the salvage setting following failed radiation therapy is limited, there is evidence to support the concept that HIFU offers comparable oncological outcomes to other established salvage treatment options for radiation-recurrent prostate cancer, with potentially less side effects. HIFU should be regarded as a viable alternative, especially for low-to-intermediate-risk cases of radiation-recurrent prostate cancer.

High-intensity focused ultrasound therapy for prostate cancer

Recent advances in high-intensity focused ultrasound, which was developed in the 1940s as a viable thermal tissue ablation approach, have increased its popularity. High-intensity focused ultrasound is currently utilized the most in Europe and Japan, but has not yet been approved by the Food and Drug Administration, USA, for this indication. The purpose of the present report is to review the scientific foundation of high-intensity focused ultrasound technology and the clinical outcomes achieved with commercially available devices. Recently published articles were reviewed to evaluate the current status of high-intensity focused ultrasound as a primary or salvage treatment option for localized prostate cancer. Improvements in the clinical outcome as a result of technical, imaging and technological advancements are described herein. A wide range of treatment options for organ-confined prostate cancer is available. However, high-intensity focused ultrasound is an attractive choice for men willing to choose less invasive options, although establishing the efficacy of high-intensity focused ultrasound requires longer follow-up periods. Technological advances, together with cultural and economic factors, have caused a dramatic shift from traditional open, radical prostatectomy to minimally invasive techniques. High-intensity focused ultrasound is likely to play a significant role in the future of oncology practice.