PSA Nadir Is a Significant Predictor of Treatment Failure after High-Intensity Focussed Ultrasound (HIFU) Treatment of Localised Prostate Cancer

Focal high-intensity focused ultrasound therapy for localized prostate cancer: An interim analysis of the multinational FASST study

BACKGROUND

High-intensity focused ultrasound (HIFU) emerged as a novel approach for the treatment of localized prostate cancer (PCa). However, prospective studies on HIFU-related outcomes and predictors of treatment failure (TF) remain scarce.

MATERIALS AND METHODS

We conducted a multinational prospective cohort study among patients undergoing HIFU therapy for localized, low- to intermediate-risk PCa. Follow-up data on serial prostate specific antigen (PSA), multi-parametric magnetic resonance imaging (mpMRI), targeted/systematic biopsies, adverse events and functional outcomes were collected. The primary endpoint was TF, defined as histologically confirmed PCa requiring whole-gland salvage treatment. Uni- and multi-variable adjusted hazard ratios (HRs) were calculated using Cox proportional hazard regression models.

RESULTS

At baseline, mean (standard deviation) age was 64.14 (7.19) years, with the majority of patients showing T-stage 1 (73.9%) and International Society of Urological Pathology grading system Grade 2 (58.8%). PSA nadir (median, 1.70 ng/mL) was reached after 6 months. Of all patients recruited, 16% had clinically significant PCa, as confirmed by biopsy, of which 13.4% had TF. Notably, T-stage and number of positive cores at initial biopsy were independent predictors of TF during follow-up (HR [95% CI] 1.27 [1.02-1.59] and 5.02 [1.80-14.03], respectively). Adverse events were minimal (17% and 8% early and late adverse events, respectively), with stable or improved functional outcomes in the majority of patients.

CONCLUSIONS

This interim analysis of a multinational study on HIFU therapy for the management of low-to-intermediate-risk PCa reveals good functional outcomes, minimal adverse events and low incidence of TF over the short-term. Data on long-term outcomes, specifically as it relates to oncological outcomes, are awaited eagerly.

Single-center, prospective phase 2 trial of high-intensity focused ultrasound (HIFU) in patients with unilateral localized prostate cancer: good functional results but oncologically not as safe as expected

PURPOSE

Focal therapy (FT) for localized prostate cancer (PCa) is only recommended within the context of clinical trials by international guidelines. We aimed to investigate oncological follow-up and safety data of focal high-intensity focused ultrasound (HIFU) treatment.

METHODS

We conducted a single-center prospective study of 29 patients with PCa treated with (focal) HIFU between 2016 and 2021. Inclusion criteria were unilateral PCa detected by mpMRI-US-fusion prostate biopsy and maximum prostate specific antigen (PSA) of 15 ng/ml. Follow-up included mpMRI-US fusion-re-biopsies 12 and 24 months after HIFU. No re-treatment of HIFU was allowed. The primary endpoint was failure-free survival (FFS), defined as freedom from intervention due to cancer progression.

RESULTS

Median follow-up of all patients was 23 months, median age was 67 years and median preoperative PSA was 6.8 ng/ml. One year after HIFU treatment PCa was still detected in 13/ 29 patients histologically (44.8%). Two years after HIFU another 7/29 patients (24.1%) were diagnosed with PCa. Until now, PCa recurrence was detected in 11/29 patients (37.93%) which represents an FFS rate of 62%.One patient developed local metastatic disease 2 years after focal HIFU. Adverse events (AE) were low with 70% of patients remaining with sufficient erectile function for intercourse and 97% reporting full maintenance of urinary continence.

CONCLUSION

HIFU treatment in carefully selected patients is feasible. However, HIFU was oncologically not as safe as expected because of progression rates of 37.93% and risk of progression towards metastatic disease. Thus, we stopped usage of HIFU in our department.

[High-intensity focused ultrasound for locally prostate cancer: An Afro-Caribbean single-center study]

INTRODUCTION

High-intensity focused ultrasound (HIFU) has proved to be effective in the treatment of localized prostate cancer. The aim of this prospective study is to assess their first oncological and functional results in an Afro-Caribbean population.

METHODS

From May 2018 to January 2020, 77 patients issued from French West Indies were included. Several treatments were carried out: whole-gland treatment hemi or focal ablation; in a primary setting (group I) or a salvage therapy (group II). PSA level was assessed at 2, 6, 9 and 12 months. MpMRI and post HIFU biopsy were performed between 6 and 9 months postoperatively. Continence, urinary end erectile functions were assessed by ICS, IPSS and IIEF scores.

RESULTS

Groupe I included 71.2% patients, group II, 28.8%. The median age was 75.4 years [IQR 69.6-79.4]. The median follow-up was 8.3 months [IQR 3.5-12.25]. At inclusion, PSA was 7.7ng/ml [IQR 5.5-11.2] in group I, and 5.9ng/ml [IQR 4.4-7.9] in group II. In the whole population, there was 73.5% negative biopsies; 14.7% of the biopsies were positive in treated zone and 11.8% in non-treated zone. Regarding morbidities, urinary incontinence appeared in 7.5% and erectile dysfunction rate was 13.2%.

CONCLUSION

Our study reveals the first experience of HIFU by Focal One® device in an Afro-Caribbean population. It seems to be a safe and reproducible treatment with acceptable oncological results and low genitourinary morbidity. Long term follow-up and a higher number of patients are necessary to validate these results.

High-intensity focused ultrasound for prostate cancer

High-intensity focused ultrasound (HIFU) is a noninvasive procedure that has shown promising results in a wide range of malignant and nonmalignant conditions, including localized prostate cancer (PCa). This review aims to describe the application of HIFU in the management of patients with PCa, explaining its basic therapeutic principles, going through the main phases during aHIFU session, and providing an overview of the main available pieces of evidence from literature. HIFU treatment for prostate cancer is increasingly performed with high success and safety. MR guidance (MR-guided HIFU) has the advantage of real-time intraprocedural thermometric feedback that ensures that the whole region of interest has been covered by critical thermal damage (and that all surrounding healthy tissues have been spared). The absence of comparative long-term trials prevents HIFU from being considered as afirst choice for the treatment of patients with PCa.

Primary whole-gland ablation for localized prostate cancer with high-intensity focused ultrasound: The important predictors of biochemical recurrence

OBJECTIVES

To identify predictive factors of biochemical recurrence for patients undergoing high-intensity focused ultrasound treatment for localized prostate cancer.

METHODS

We retrospectively identified patients receiving whole-gland prostate ablation with high-intensity focused ultrasound for localized prostate cancer from 2009 to 2015. All the patients received pre-high-intensity focused ultrasound radical transurethral resection of the prostate. We included perioperative parameters as follows: age, preoperative prostate volume, stage of operation, initial prostate-specific antigen, T stage, postoperative prostate-specific antigen nadir, Gleason score, time to prostate-specific antigen nadir and the presence of prostate-specific antigen biochemical recurrence. Multivariable Cox regression and Kaplan-Meier analysis were used for investigating predictors of recurrence, and receiver operating characteristic analysis was used for the cut-off values of prostate-specific antigen nadir.

RESULTS

Among 182 patients, 26.9% had prostate-specific antigen biochemical recurrence after high-intensity focused ultrasound during the median follow-up period of 32.21 months. Gleason score ≥7 (Gleason score 7, hazard ratio 2.877, P = 0.027), stage ≥T2b (T2b, hazard ratio 3.16, P = 0.027) and prostate-specific antigen nadir (hazard ratio 1.11, P < 0.001) were statistically significant, whereas there was no significance in prostate volume and initial prostate-specific antigen. We posit that a cut-off level of prostate-specific antigen nadir 0.43 ng/mL might be considered as an independent predictive factor for prostate-specific antigen biochemical recurrence in high-intensity focused ultrasound patients in multivariate analysis (P < 0.001, hazard ratio 7.39, 95% confidence interval 3.56-15.37), and created a new nadir-related prediction model for biochemical recurrence prediction.

CONCLUSIONS

Postoperative prostate-specific antigen nadir of 0.43 ng/mL can be considered an important predictive factor for biochemical recurrence in primary whole-prostate gland high-intensity focused ultrasound treatment, and the nadir-related prediction model might provide a reference for early salvage treatment. Furthermore, Gleason score ≥7, stage ≥T2b might be associated with unfavorable outcomes, although prostate volume and higher initial prostate-specific antigen appear not to be associated with biochemical recurrence for the high-intensity focused ultrasound treatment.

[High intensity focused ultrasound (HIFU) : Importance in the treatment of prostate cancer]

BACKGROUND

High intensity focused ultrasound (HIFU) has been used since the beginning of the 1990s as an alternative treatment for prostate cancer.

OBJECTIVE

Overview of the current status and critical review of the different indications for HIFU in the treatment of prostate cancer.

MATERIAL AND METHODS

Review of the current literature on the indications, side effects, oncologic results and current guideline recommendations.

RESULTS

The principle of HIFU is based on high energy sound waves, which lead to coagulation necrosis at the focal point. It can be applied for different indications: complete ablation of prostatic tissue is attempted in whole gland HIFU in the primary treatment of localized prostate cancer. There are several case series in the current literature with a maximum median follow-up of 8.1 years. The main side effect is the formation of bladder neck sclerosis. A further indication is for salvage HIFU in patients with localized recurrent prostate cancer after radiotherapy. This is a high-risk procedure due to increased risk of incontinence and formation of rectourethral fistula. Focal therapy is an innovative field aiming at partial prostate gland ablation with HIFU thereby reducing side effects. Technical improvements in HIFU enable treatment planning with fusion of multiparametric magnetic resonance imaging (mpMRI). Due to the experimental character, this should only be carried out within clinical trials.

DISCUSSION

Due to a lack of prospective randomized trials and limited long-term results, whole gland HIFU is considered differently in the guidelines of European countries. Focal therapy is still experimental and should only be carried out within clinical trials.

Salvage high-intensity focused ultrasound (HIFU) for locally recurrent prostate cancer after failed radiation therapy: Multi-institutional analysis of 418 patients

OBJECTIVE

To report the oncological outcome of salvage high-intensity focused ultrasound (S-HIFU) for locally recurrent prostate cancer after external beam radiotherapy (EBRT) from a multicentre database.

PATIENTS AND METHODS

This retrospective study comprises patients from nine centres with local recurrent disease after EBRT treated with S-HIFU from 1995 to 2009. The biochemical failure-free survival (bFFS) rate was based on the 'Phoenix' definition (PSA nadir + 2 ng/mL). Secondary endpoints included progression to metastasis and cancer-specific death. Kaplan-Meier analysis was performed examining overall (OS), cancer-specific (CSS) and metastasis-free survival (MFS). Adverse events and quality of life status are reported.

RESULTS

In all, 418 patients with a mean (SD) follow-up of 3.5 (2.5) years were included. The mean (SD) age was 68.6 (5.8) years and the PSA level before S-HIFU was 6.8 (7.8) ng/mL. The median PSA nadir after S-HIFU was 0.19 ng/mL. The OS, CSS and MFS rates at 7 years were 72%, 82% and 81%, respectively. At 5 years the bFFS rate was 58%, 51% and 36% for pre-EBRT low-, intermediate- and high-risk patients, respectively. The 5-year bFFS rate was 67%, 42% and 22% for pre-S-HIFU PSA level ≤4, 4-10 and ≥10 ng/mL, respectively. Complication rates decreased after the introduction of specific post-RT parameters: incontinence (grade II or III) from 32% to 19% (P = 0.002); bladder outlet obstruction or stenosis from 30% to 15% (P = 0.003); recto-urethral fistula decreased from 9% to 0.6% (P < 0.001). Study limitations include being a retrospective analysis from a registry with no control group.

CONCLUSION

S-HIFU for locally recurrent prostate cancer after failed EBRT is associated with 7-year CSS and MFS rates of >80% at a price of significant morbidity. S-HIFU should be initiated early following EBRT failure.

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.

A Whole of Population, Multiuser Series of High-Intensity Focused Ultrasound for Management of Localized Prostate Cancer: Outcomes and Implications

PURPOSE

To determine the oncologic and complication outcomes of treatment of patients with localized prostate cancer by high intensity focused ultrasound (HIFU) for primary management of prostate cancer in a whole of population, multiuser series.

PATIENTS AND METHODS

We created a centralized database-accessible only by nonurologist researchers-within a cancer epidemiology center, after ethics approval from that institution. A single researcher prospectively entered baseline, treatment, and clinical/biochemical follow-up data from all patients treated with HIFU in the state of Victoria over the study period.

RESULTS

We accrued 108 patients, of whom 103 had been staged as having clinically localized disease. Ninety-three patients (86.1%) had low- or intermediate-risk prostate cancer. Forty-four patients (40.5%) had persistent mild urinary incontinence at 3 months after treatment, and 3 of these ultimately underwent further surgical procedures to correct incontinence. Twenty-seven patients (25%) additionally experienced occasions of urinary retention in the first 3 months after treatment because of passage of tissue. Twenty-nine patients had achieved a prostate-specific antigen level of <0.2 ng/mL at 3 months after HIFU. Fifty-six patients underwent post-HIFU prostate biopsy, and this was positive for residual cancer in 51 cases. Forty-five of the patients who had a positive post-HIFU biopsy underwent secondary treatment for prostate cancer.

CONCLUSION

Oncologic control and complication outcomes in this cohort were inferior to those previously reported for HIFU in single-user series. Given the population-based multiuser nature of our series, we believe our observations are more likely to reflect the community outcomes that might be expected from widespread adoption of HIFU than generalizing from single-operator series.

Single session of high-intensity focused ultrasound for localized prostate cancer: treatment outcomes and potential effect as a primary therapy

Purpose

To investigate the treatment outcomes of a single-session high-intensity focused ultrasound (HIFU) using the Sonablate^® for patients with localized prostate cancer.

Methods

Biochemical failure was defined according to the Stuttgart definition [a rise of 1.2 ng/ml or more above the nadir prostate-specific antigen (PSA)] and the Phoenix definition (a rise of 2 ng/ml or more above the nadir PSA). Disease-free survival rate was defined using the Phoenix criteria and positive follow-up biopsy.

Results

A total of 171 patients were identified. Fifty-two (30.4 %) patients were identified to be with D’Amico low risk, 47 (27.5 %) with intermediate risk, and 72 (42.1 %) with high risk. In the median follow-up time of 43 months, there was 44 (25.7 %) and 36 (21.1 %) patients experienced biochemical failure for Stuttgart and Phoenix definition with mean (±SD) time to failure of 17.8 ± 2.1 and 19.4 ± 2.3 months, respectively. A total of 44 (25.7 %) patients were diagnosed as disease failure. Cox multivariate analysis revealed PSA nadir level (PSA cutoff = 0.2 ng/ml; HR = 9.472, 95 % CI 4.527–19.820, p < 0.001) and D’amico risk groups [HR = 3.132 (95 % CI 1.251–6.389), p = 0.033] were the predictor for failure in single-session HIFU.

Conclusions

Single-session HIFU treatment using the Sonablate^® seems to be potentially curative approach. When treated carefully with neoadjuvant hormonal therapy or preoperative transurethral resection of the prostate, higher-risk disease might be able to choose this minimally invasive procedure as primary therapy.

Salvage radiotherapy after high-intensity focused ultrasound treatment for localized prostate cancer: feasibility, tolerance and efficacy

BACKGROUND

The objective of this study is to evaluate the feasibility, tolerance and efficacy of salvage external beam radiotherapy (EBRT) in persistent or recurrent prostate cancer after failed high intensity focused ultrasound (HIFU) therapy.

METHODS

We reviewed data on tolerance and oncologic outcomes for all patients with biopsy-proven locally recurrent or persistent prostate cancer who underwent salvage EBRT in our department between April 2004 and June 2008. Minimum follow-up for inclusion was 2 years. Failure with EBRT was defined as biochemical relapse (Phoenix definition) or introduction of androgen deprivation therapy (ADT). Gastrointestinal and urinary toxicity and urinary stress incontinence were scored at 12 and 24 months (Radiation Therapy Oncology Group and Ingelman Sundberg rating, respectively).

RESULTS

The mean age of the patients was 68.8 years (range: 60-79). Mean prostate-specific antigen (PSA) before EBRT was 5.57 ng/mL (range: 2.5-14.8). Median follow-up was 36.5 ± 10.9 months (range: 24-54). No patient received adjunctive ADT. The EBRT course was well-tolerated and completed by all patients. The mean PSA nadir was 0.62 ng/mL (range: 0.03-2.4) and occurred after a median of 22 months (range: 12-36). One patient experienced biochemical failure and was prescribed ADT 30 months after EBRT. The disease-free survival rate was 83.3% at 36.5 months. There was no major EBRT-related toxicity at 12 or 24 months.

CONCLUSIONS

Our early clinical results confirm the feasibility and good tolerance of salvage radiotherapy after HIFU failure. Oncological outcomes were promising. A prospective study with longer follow-up is needed to identify factors predictive of success for salvage EBRT therapy after HIFU failure.

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.

[Tumour recurrence]

In Chap. 6 the German S3 guideline on prostate cancer addresses the issue of tumour recurrence following primary local treatment with curative intent, i.e. after radical prostatectomy or a form of radiotherapy. PSA recurrence after radical surgery is defined as a rising PSA of 0.2 ng/ml and after radiotherapy as an increase of at least 2 ng/ml above the individual nadir. Factors for the clinical judgement that a local recurrence is likely are empirical indicators from the primary tumour diagnosis and the PSA course after primary treatment. Salvage external beam radiotherapy after radical surgery does not require the histological proof of a local recurrence and should be initiated early (PSA < 0.5 ng/ml). Before salvage radical prostatectomy, which carries a higher complication rate, the presence of a local recurrence should be histologically verified.

Clinical and future applications of high intensity focused ultrasound in cancer

High intensity focused ultrasound (HIFU) or focused ultrasound (FUS) is a promising modality to treat tumors in a complete, non invasive fashion where online image guidance and therapy control can be achieved by magnetic resonance imaging (MRI) or diagnostic ultrasound (US). In the last 10 years, the feasibility and the safety of HIFU have been tested in a growing number of clinical studies on several benign and malignant tumors of the prostate, breast, uterine, liver, kidney, pancreas, bone, and brain. For certain indications this new treatment principle is on its verge to become a serious alternative or adjunct to the standard treatment options of surgery, radiotherapy, gene therapy and chemotherapy in oncology. In addition to the now clinically available thermal ablation, in the future, focused ultrasound at much lower intensities may have the potential to become a major instrument to mediate drug and gene delivery for localized cancer treatment. We introduce the technology of MRI guided and ultrasound guided HIFU and present a critical overview of the clinical applications and results along with a discussion of future HIFU developments.

High-intensity focused ultrasound for prostate cancer: a practice guideline

OBJECTIVE

The aim of this practice guideline was to develop evidence-based recommendations for clinicians on the use of high-intensity focused ultrasound (HIFU) in patients with localized prostate cancer.

METHODS

The guideline was developed using the methods of Cancer Care Ontario's Program in Evidence-Based Care (PEBC). The core methodology of the PEBC's guideline development process is systematic review. A comprehensive literature search was undertaken to identify high-quality studies, reviews and other practice guidelines on the use of HIFU in prostate cancer. The evidence formed the basis of the recommendations, which were reviewed and amended where necessary, by clinical experts in medical and radiation oncology and urology.

RESULTS

The literature review yielded limited evidence. No randomized controlled trials or meta-analyses comparing HIFU with currently accepted management approaches were identified. The body of evidence is primarily based on data from case series. Internal feedback was provided by the PEBC Genitourinary Disease Site Group membership and the Report Approval Panel. External peer review included targeted review by clinical experts specifically requested to comment on the guideline, and professional consultation through an online survey of health care professionals.

CONCLUSION

HIFU is currently not recommended as an alternative to accepted curative treatment approaches for localized prostate cancer.

Transrectal high-intensity focused ultrasound for the treatment of prostate cancer: past, present, and future

Upon a review of recently published articles on high-intensity focused ultrasound (HIFU) in the treatment of prostate cancer, we evaluated the current status of HIFU as a primary treatment option for localized prostate cancer and its use as salvage therapy when radiation failed. We also briefly discuss current issues in indications, definition of response, and finally the future of HIFU development.

Comparison of penile size and erectile function after high-intensity focused ultrasound and targeted cryoablation for localized prostate cancer: a prospective pilot study

INTRODUCTION

Erectile dysfunction (ED) represents a common quality-of-life issue of any treatment used for prostate cancer, including high-intensity focused ultrasound (HIFU) and targeted cryoablation of the prostate (TCAP). There is a paucity of comparative studies regarding the difference in the erectile function and penile size of patients undergoing HIFU or TCAP.

AIM

The aim of this study is to compare the erectile function and penile size of patients undergoing HIFU or TCAP.

METHODS

Patients with a preoperative erectile function domain of the International Index of Erectile Function (IIEF-EF) score ≥ 26 were prospectively included. All patients were preoperatively evaluated by IIEF-EF and penile color Doppler ultrasound. Penile length and circumference were measured in flaccidity and at maximum erection. At 6, 12, 18, 24, 36 months after surgery, patients were assessed with the same protocol.

MAIN OUTCOME MEASURES

IIEF-EF score, penile color Doppler ultrasound, penile length, and circumference at different time points.

RESULTS

There were 55 patients in the HIFU group and 47 in the TCAP group. At each time point, there were significant differences in mean IIEF-EF scores and penile color Doppler results between the two groups. At 36 months, TCAP patients experienced lower erectile function recovery rate compared with HIFU patients (TCAP=46.8%; HIFU=65.5%; P=0.021). No significant decreases in penile length and circumference were found in the two groups (all P values ≥ 0.05).

CONCLUSIONS

Our data demonstrate TCAP caused significantly decreased erectile function than HIFU. We found no change in penile size after HIFU or TCAP. The option of HIFU may be more attractive to the patient who wants to avoid ED afterward, to maintain their quality of life.

Correlation of prostate-specific antigen nadir and biochemical failure after high-intensity focused ultrasound of localized prostate cancer based on the Stuttgart failure criteria - analysis from the @-Registry

OBJECTIVE

•To determine if the prostate-specific antigen (PSA) nadir after high-intensity focused ultrasound (HIFU) can be used as a predictor of the biochemical disease-free survival rate (DFSR).

PATIENTS AND METHODS

•Patient data were derived from the multicentre-based @-Registry, the largest registry to report outcomes in patients with localized prostate cancer after Ablatherm® HIFU. •PSA level was measured at 3-month intervals. Patients were stratified into four PSA nadir groups: group 1, ≤0.2 ng/mL; group 2, 0.21-0.5 ng/mL; group 3, 0.51-1 ng/mL; and group 4, >1 ng/mL. •Biochemical treatment failure was defined according to the Stuttgart definition (PSA nadir + 1.2 ng/mL) and the Phoenix definition (PSA nadir + 2 ng/mL). •Biopsy was performed at 3-6 months post-HIFU or if a PSA level was recorded that was considered clinically relevant.

RESULTS

•The present study included 804 patients. Biochemical treatment success rates at 5 years according to the Stuttgart definition for the four PSA nadir sub-groups were as follows: 84, 64, 40 and 30% for groups 1-4, respectively. •The equivalent 5-year biochemical success rates using the Phoenix definition were 94, 74, 66 and 47%, respectively. •Significantly more patients had a negative biopsy in the lowest PSA nadir group than in the other sub-groups (91.6 vs 73.1%; P < 0.001). •The present study is limited by its retrospective nature and variations in clinical practice across participating centres.

CONCLUSION

•This multicentre analysis confirms that PSA nadir after HIFU predicts biochemical DFSR in a statistically significant manner.

A Bayesian method to estimate the optimal threshold of a longitudinal biomarker

The objective of this study was to develop methods to estimate the optimal threshold of a longitudinal biomarker and its credible interval when the diagnostic test is based on a criterion that reflects a dynamic progression of that biomarker. Two methods are proposed: one parametric and one non-parametric. In both the cases, the Bayesian inference was used to derive the posterior distribution of the optimal threshold from which an estimate and a credible interval could be obtained. A numerical study shows that the bias of the parametric method is low and the coverage probability of the credible interval close to the nominal value, with a small coverage asymmetry in some cases. This is also true for the non-parametric method in case of large sample sizes. Both the methods were applied to estimate the optimal prostate-specific antigen nadir value to diagnose prostate cancer recurrence after a high-intensity focused ultrasound treatment. The parametric method can also be applied to non-longitudinal biomarkers.

High-intensity focused ultrasound for prostate cancer: a systematic review

High-intensity focused ultrasound (HIFU) has recently been promoted as a non-invasive treatment option for prostate cancer. This systematic review sought to evaluate the evidence comparing it with standard treatment in patients with localised prostate cancer. The literature review included searches of MEDLINE, EMBASE, the Cochrane Library, annual meetings' abstracts and websites of evidence-based practice guideline producers. Studies were included if they were randomised controlled trials comparing HIFU with current management approaches, or were meta-analyses, systematic reviews or practice guidelines addressing HIFU. No randomised controlled trials or meta-analyses were identified. Seven systematic reviews and two practice guidelines were identified; neither contained randomised controlled trials. Adjusting the selection criteria to include case series found 34 clinical studies of HIFU. Twenty-nine evaluated HIFU as the primary treatment and five examined HIFU as salvage treatment for recurrence after radiotherapy. In most studies the outcomes used to determine efficacy were negative biopsy rates or prostate-specific antigen (PSA) levels. Among the 29 studies of HIFU as the primary treatment, negative biopsy rates ranged from 35 to 95% in 21 studies, a PSA nadir of ≤0.5 ng/ml ranged from 55 to 91% in 10 studies and mean PSA nadirs ranged from 0 to 1.9 ng/ml in 17 studies. Five studies reported 5-year disease-free survival rates ranging from 55 to 95%. Among five studies of HIFU as salvage treatment, negative biopsy rates ranged from 73 to 84% in four studies, a PSA nadir of ≤0.5 ng/ml ranged from 57 to 66% in three studies and mean PSA nadirs were 1.97 and 2.38 ng/ml in two studies, respectively. Current evidence on HIFU use in prostate cancer patients is of low quality, rendering it difficult to draw conclusions about its efficacy. Until results from case series are confirmed in prospective studies, the widespread use of HIFU is not supported.

Anterior perirectal fat tissue thickness is a strong predictor of recurrence after high-intensity focused ultrasound for prostate cancer

OBJECTIVE

To evaluate if and why obesity affects the clinical outcome in patients undergoing high-intensity focused ultrasound (HIFU) treatment for prostate cancer (CaP).

METHODS

115 patients who underwent HIFU treatment for localized CaP were categorized as obese, overweight or normal according to body mass index (BMI). The thickness of the anterior perirectal fat tissue (APFT) was measured by transrectal ultrasonography. Treatment was considered to have failed in the case of biochemical failure according to the Phoenix definition, positive follow-up biopsy or initiation of salvage therapy. Cox proportional hazards analyses were used to identify possible predictors for disease free survival (DFS), and an experimental fat tissue model was made to evaluate the ablation effect at the target tissue.

RESULTS

According to the classification by the Western Pacific Regional Office of WHO, 43 patients were of normal weight, 24 were overweight and 48 were obese. The BMI groups did not differ in Gleason score, prostate-specific antigen level at diagnosis or clinical stage. There were, however, significant correlations between BMI and prostate-specific antigen nadir (P < 0.001), and BMI and APFT thickness (P < 0.01). Multivariate analyses showed that BMI fails to be an independent predictor of DFS when APFT (P < 0.0001) is included as a variable.

CONCLUSIONS

Our results suggest that APFT thickness, for which obesity could be a useful surrogate, might represent the causative factor for poor clinical outcome after transrectal HIFU treatment for CaP.

High-intensity focused ultrasound: where are we and where to from here?

High-intensity focused ultrasound (HIFU) has evolved significantly from early work treating cerebral lesions. The ability to treat deep soft-tissue lesions without damaging superficial structures led to it being used for prostate cancer treatment both in the primary and salvage setting. Primary HIFU treatment for prostate cancer leads to 5-year disease free survival rates of up to 70-80% in selected patients with little morbidity; however, comparative studies with established treatment modalities are lacking. Salvage treatment with HIFU leads to significantly more morbidity than primary treatment yet the morbidity appears the same or less than other salvage treatments following external-beam radiation treatment. We believe that with the development of more advanced imaging techniques combined with multimodality prostate imaging that HIFU's future lies in focal treatment of prostate cancer.

High-intensity-focused ultrasound in the treatment of primary prostate cancer: the first UK series

Background:

The use of minimally invasive ablative therapies in localised prostate cancer offer potential for a middle ground between active surveillance and radical therapy.

Methods:

An analysis of men with organ-confined prostate cancer treated with transrectal whole-gland HIFU (Sonablate 500) between 1 February 2005 and 15 May 2007 was carried out in two centres. Outcome data (side-effects using validated patient questionnaires, biochemical, histology) were evaluated.

Results:

A total of 172 men were treated under general anaesthetic as day-case procedures with 78% discharged a mean 5 h after treatment. Mean follow-up was 346 days (range 135–759 days). Urethral stricture was significantly lower in those with suprapubic catheter compared with urethral catheters (19.4 vs 40.4%, P=0.005). Antibiotics were given to 23.8% of patients for presumed urinary tract infection and the rate of epididymitis was 7.6%. Potency was maintained in 70% by 12 months, whereas mild stress urinary incontinence (no pads) was reported in 7.0% (12 out of 172) with a further 0.6% (1 out of 172) requiring pads. There was no rectal toxicity and no recto-urethral fistulae. In all, 78.3% achieved a PSA nadir ⩽0.5 μg ml⁻¹ at 12 months, with 57.8% achieving ⩽0.2 μg ml⁻¹. Then, 8 out of 13 were retreated with HIFU, one had salvage external beam radiotherapy and four chose active surveillance for small-volume low-risk disease. Overall, there was no evidence of disease (PSA <0.5 μg ml⁻¹ or negative biopsy if nadir not achieved) after one HIFU session in 92.4% (159 out of 172) of patients.

Conclusion:

HIFU is a minimally invasive, day-case ablative technique that can achieve good biochemical outcomes in the short term with minimal urinary incontinence and acceptable levels of erectile dysfunction. Long-term outcome needs further evaluation and the inception of an international registry for cases treated using HIFU will significantly aid this health technology assessment.