High-intensity focused ultrasound therapy for clinically localized prostate cancer

Oncological and Functional Outcomes of Whole-Gland HIFU as the Primary Treatment for Localized Prostate Cancer: A Systematic Review

INTRODUCTION

High-intensity focused ultrasound (HIFU) is regarded as a promising alternative treatment option for localized prostate cancer (PCa) as it has been proposed to offer similar oncologic control to the standard of care, but with significantly reduced treatment-related side effects. This systematic literature review assesses the available evidence of whole-gland HIFU as primary treatment for localized PCa.

METHODS

MEDLINE (PubMed) was searched for studies investigating oncological and functional outcomes following whole-gland HIFU as primary treatment for localized PCa. Our primary outcomes for the review were biochemical disease-free survival rates (BDFS), overall and PCa-specific survival rates as well as negative biopsy rates. Our secondary outcomes were functional results and complications of the treatment.

RESULTS

A total of 375 articles were identified, of which 35 were included in the present review. All 35 articles were prospective or retrospective case series. Mean/median duration of follow-up across studies was 10.9 to 94 months, and 6618 patients were included in the review. The BDFS rate varied greatly across studies from 21.7% to 89.2% during follow-up. The 10-year PCa-specific survival rate following HIFU was 90%, 99%, and 100% in 3 studies. Negative biopsy rates post-HIFU ranged from 20% to 92.7% across studies. Common side effects to HIFU included urinary incontinence (grade 1: 0%-22.7%), erectile dysfunction (11.6%-77.1%), urinary tract infections (1.5%-47.9%), and bladder outlet obstruction mainly as urethral strictures (7%-41.2%).

CONCLUSION

Great variation in oncological and functional outcomes was seen across studies. More prospective trials are needed before whole-gland HIFU can be considered as a treatment option for localized PCa.

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.

Pre-Exposure to Stress-Inducing Agents Increase the Anticancer Efficacy of Focused Ultrasound against Aggressive Prostate Cancer Cells

Despite the initial success in treatment of localized prostate cancer (PCa) using surgery, radiation or hormonal therapy, recurrence of aggressive tumors dictates morbidity and mortality. Focused ultrasound (FUS) is being tested as a targeted, noninvasive approach to eliminate the localized PCa foci, and strategies to enhance the anticancer potential of FUS have a high translational value. Since aggressive cancer cells utilize oxidative stress (Ox-stress) and endoplasmic reticulum stress (ER-stress) pathways for their survival and recurrence, we hypothesized that pre-treatment with drugs that disrupt stress-signaling pathways in tumor cells may increase FUS efficacy. Using four different PCa cell lines, i.e., LNCaP, C4-2B, 22Rv1 and DU145, we tested the in vitro effects of FUS, alone and in combination with two clinically tested drugs that increase Ox-stress (i.e., CDDO-me) or ER-stress (i.e., nelfinavir). As compared to standalone FUS, significant (p < 0.05) suppressions in both survival and recurrence of PCa cells were observed following pre-sensitization with low-dose CDDO-me (100 nM) and/or nelfinavir (2 µM). In drug pre-sensitized cells, significant anticancer effects were evident at a FUS intensity of as low as 0.7 kW/cm². This combined mechanochemical disruption (MCD) approach decreased cell proliferation, migration and clonogenic ability and increased apoptosis/necrosis and reactive oxygen species (ROS) production. Furthermore, although activated in cells that survived standalone FUS, pre-sensitization with CDDO-me and/or nelfinavir suppressed both total and activated (phosphorylated) NF-κB and Akt protein levels. Thus, a combined MCD therapy may be a safe and effective approach towards the targeted elimination of aggressive PCa cells.

High-intensity focused ultrasound for the treatment of prostate cancer: assessing location of failure after focal therapy in prostate cancer and review of histological characteristics and clinicopathologic correlates after treatment-a 5-year experience

High-intensity focused ultrasound (HIFU) is a noninvasive treatment option used for localized prostate cancer or salvage surgery after failed radiation therapy. Histological changes in post-treatment needle biopsies are reviewed to better understand HIFU failures. Between 2016 and 2021, 50 patients with localized prostate cancer were enrolled and treated in this study. Of these, 10 patients underwent salvage therapy after radiation failure and 7 did not have post-treatment needle biopsies available for review and were excluded. Inclusion criteria included pathologically confirmed prostate cancer and clinical stage T1/T2 disease. We describe the histological changes in post-treatment needle biopsies as part of routine follow-up. Biopsies were examined for presence, distribution and extent of residual adenocarcinoma, Gleason score, and ablative tissue changes. A total of 33 patients underwent HIFU hemi-ablation treatment of localized prostate cancer as primary treatment with post-treatment biopsies available for review. The average mean age of the patients was 64 years (range, 52-81 years). The average PSA (prostate-specific antigen) level of the patients was 6.3 ng/mL (range, 2.4-14.7 ng/mL). The Gleason scores assigned in pretreatment prostate needle biopsies are as follows: 3 + 3 (1 case, 3%), 3 + 4 (21 cases, 64%), 4 + 3 (9 cases, 27%), and 4 + 4 (2 cases, 6%). In post-treatment needle biopsies, 33 cases (100%) showed variable degrees of fibrosis ranging from mild to moderate. Twenty-four of 33 cases (73%) showed necrosis usually associated with acute and/or chronic inflammation. Histological examination of benign glands revealed glandular heterogeneity including atrophy and basal cell hyperplasia. Eight cases (24%) had residual prostatic adenocarcinoma after treatment, of which 4 cases were assigned Gleason score: ≥3 + 4. In cases with residual adenocarcinoma, 8 cases (100%) showed nuclear enlargement, 5 cases (63%), cytoplasmic vacuolization, and 1 case (13%) showed nuclear pyknosis; otherwise, no discernible effects of treatment were seen. Morphological alterations included a spectrum of changes ranging from extensive coagulative stromal necrosis secondary to thermal injury to atrophic changes in benign prostatic tissue after HIFU treatment. Our findings also support the hypothesis that HIFU failure results from inadequate targeting rather than failure within a treated zone.

Ultrasound Therapy, Chemotherapy and Their Combination for Prostate Cancer

Prostate cancer is the second leading cause of cancer death in men. Its current treatment includes various physical and chemical approaches for the localized and advanced prostate cancer [e.g. metastatic castrate resistant prostate cancer (mCRPC)]. Although many new drugs are now available for prostate cancer, none is suitable for local treatment that can reduce adverse effects often associated with the current physical treatment. Of the drugs approved by FDA for mCRPC, the best mean improvement in overall survival is only about 4.8 months. Therefore, there is a need for improved treatment approaches for prostate cancer, especially drug-resistant cancer.

Ultrasound therapy represents a useful new physical approach for the drug-resistant cancer treatment by facilitating the entry of the related chemotherapy drug into the target cancer cells. There are two versions of ultrasound: High Intensity Focused Ultrasound (HIFU) and Low Intensity Pulsed Ultrasound (LIPUS). HIFU has been a promising treatment option for prostate cancer due to its noninvasiveness and various biological effects on cancer tissue. It has been approved for the treatment of cancer and in recent years there have been numerous findings suggesting HIFU can reduce cancer cell viability and possibly reverse the spread of cancerous tumors. LIPUS is currently being studied as an alternative treatment option for prostate cancer. Preliminary studies have found LIPUS to reduce cancer cell viability without the side effects seen in HIFU. Reversible cell membrane damage caused by LIPUS could allow increased uptake of anticancer drugs, enhancing cytotoxicity and death of cancer cells. In this way, a low dose of anticancer drug is more effective toward cancer cells while there is less damage to normal cells. The combination of LIPUS with certain chemotherapeutic agents can be an exciting physical-chemical combination therapy for prostate cancer. This review will focus on this topic as well as the clinical use of HIFU to provide an understanding of their current use and future potential role for prostate cancer therapy.

Functional micro/nanobubbles for ultrasound medicine and visualizable guidance

Chemically functionalized gas-filled bubbles with a versatile micro/nano-sized scale have witnessed a long history of developments and emerging applications in disease diagnosis and treatments. In combination with ultrasound and image-guidance, micro/nanobubbles have been endowed with the capabilities of biomedical imaging, drug delivery, gene transfection and disease-oriented therapy. As an external stimulus, ultrasound (US)-mediated targeting treatments have been achieving unprecedented efficiency. Nowadays, US is playing a crucial role in visualizing biological/pathological changes in lives as a reliable imaging technique and a powerful therapeutic tool. This review retrospects the history of ultrasound, the chemistry of functionalized agents and summarizes recent advancements of functional micro/nanobubbles as US contrast agents in preclinical and transclinical research. Latest ultrasound-based treatment modalities in association with functional micro/nanobubbles have been highlighted as their great potentials for disease precision therapy. It is believed that these state-of-the-art micro/nanobubbles will become a booster for ultrasound medicine and visualizable guidance to serve future human healthcare in a more comprehensive and practical manner.

Direct Acoustic Imaging Using a Piezoelectric Organic Light-Emitting Diode

Conventional ultrasonic imaging requires acoustic scanning over a target object using a piezoelectric transducer array, followed by signal processing to reconstruct the image. Here, we report a novel ultrasonic imaging device that can optically display an acoustic signal on the surface of a piezoelectric transducer. By fabricating an organic light-emitting diode (OLED) on top of a piezoelectric crystal, lead zirconate titanate (PZT), an acousto-optical piezoelectric OLED (p-OLED) transducer is realized, converting an acoustic wave profile directly to an optical image. Because of the integrated device architecture, the resulting p-OLED features a high acousto-optic conversion efficiency at the resonance frequency, providing a piezoelectric field to drive the OLED. By incorporating an electrode array in the p-OLED, we demonstrate a novel tomographic ultrasound imaging device that is operated without a need for conventional signal processing.

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.

Mechanochemical Disruption Suppresses Metastatic Phenotype and Pushes Prostate Cancer Cells toward Apoptosis

Chemical-based medicine that targets specific oncogenes or proteins often leads to cancer recurrence due to tumor heterogeneity and development of chemoresistance. This challenge can be overcome by mechanochemical disruption of cancer cells via focused ultrasound (FUS) and sensitizing chemical agents such as ethanol. We demonstrate that this disruptive therapy decreases the viability, proliferation rate, tumorigenicity, endothelial adhesion, and migratory ability of prostate cancer cells in vitro. It sensitized the cells to TNFR1-- and Fas--mediated apoptosis and reduced the expression of metastatic markers CD44 and CD29. Using a prostate cancer xenograft model, we observed that the mechanochemical disruption led to complete tumor regression in vivo. This switch to a nonaggressive cell phenotype was caused by ROS and Hsp70 overproduction and subsequent impairment of NFκB signaling. FUS induces mechanical perturbations of diverse cancer cell populations, and its combination with agents that amplify and guide remedial cellular responses can stop lethal cancer progression. IMPLICATIONS: Mechanochemical disruption therapy in which FUS is combined with ethanol can be curative for locally aggressive and castration-resistant prostate cancer.

Focused ultrasound: tumour ablation and its potential to enhance immunological therapy to cancer

Various kinds of image-guided techniques have been successfully applied in the last years for the treatment of tumours, as alternative to surgical resection. High intensity focused ultrasound (HIFU) is a novel, totally non-invasive, image-guided technique that allows for achieving tissue destruction with the application of focused ultrasound at high intensity. This technique has been successfully applied for the treatment of a large variety of diseases, including oncological and non-oncological diseases. One of the most fascinating aspects of image-guided ablations, and particularly of HIFU, is the reported possibility of determining a sort of stimulation of the immune system, with an unexpected "systemic" response to treatments designed to be "local". In the present article the mechanisms of action of HIFU are described, and the main clinical applications of this technique are reported, with a particular focus on the immune-stimulation process that might originate from tumour ablations.

High-Intensity Focused Ultrasound for the Treatment of Prostate Cancer: A Review

Over the past 25 years, the average life expectancy for men has increased almost 4 years, and the age of prostate cancer detection has decreased an average of 10 years with diagnosis increasingly made at early-stage disease where curative therapy is possible. These changing trends in the age and extent of malignancy at diagnosis have revealed limitations in conventional curative therapies for prostate cancer, including a significant risk of aggressive cancer recurrence, and the risk of long-term genitourinary morbidity and its detrimental impact on patient's quality of life (QOL). Greater awareness of the shortcomings in radical prostatectomy, external radiotherapy, and brachytherapy has prompted the search for alternative curative therapies that offer comparable rates of cancer control and less treatment-related morbidity to better preserve QOL. High-intensity focused ultrasound (HIFU) possesses characteristics that make it an attractive curative therapy option. HIFU is a noninvasive approach that uses precisely delivered ultrasound energy to achieve tumor cell necrosis without radiation or surgical excision. In current urologic oncology, HIFU is used clinically in the treatment of prostate cancer and is under experimental investigation for therapeutic use in multiple malignancies. Clinical research on HIFU therapy for localized prostate cancer began in the 1990s, and there have now been ∼65,000 prostate cancer patients treated with HIFU, predominantly with the Ablatherm (EDAP TMS, Lyon, France) device. Neoadjuvant transurethral resection of the prostate has been combined with HIFU since 2000 to reduce prostate size, facilitate tissue destruction, and to minimize side effects. Advances in imaging technologies are expected to further improve the already superior efficacy and morbidity outcomes, and ongoing investigation of HIFU as a focal therapy in salvage and palliative indications is serving to expand the role of HIFU as a highly versatile noninvasive therapy for prostate cancer.

High-Intensity Focused Ultrasound: Current Status for Image-Guided Therapy

Image-guided high-intensity focused ultrasound (HIFU) is an innovative therapeutic technology, permitting extracorporeal or endocavitary delivery of targeted thermal ablation while minimizing injury to the surrounding structures. While ultrasound-guided HIFU was the original image-guided system, MR-guided HIFU has many inherent advantages, including superior depiction of anatomic detail and superb real-time thermometry during thermoablation sessions, and it has recently demonstrated promising results in the treatment of both benign and malignant tumors. HIFU has been employed in the management of prostate cancer, hepatocellular carcinoma, uterine leiomyomas, and breast tumors, and has been associated with success in limited studies for palliative pain management in pancreatic cancer and bone tumors. Nonthermal HIFU bioeffects, including immune system modulation and targeted drug/gene therapy, are currently being explored in the preclinical realm, with an emphasis on leveraging these therapeutic effects in the care of the oncology patient. Although still in its early stages, the wide spectrum of therapeutic capabilities of HIFU offers great potential in the field of image-guided oncologic therapy.

Image-guided focal therapy for prostate cancer

The adoption of routine prostate specific antigen screening has led to the discovery of many small and low-grade prostate cancers which have a low probability of causing mortality. These cancers, however, are often treated with radical therapies resulting in long-term side effects. There has been increasing interest in minimally invasive focal therapies to treat these tumors. While imaging modalities have improved rapidly over the past decade, similar advances in image-guided therapy are now starting to emerge--potentially achieving equivalent oncologic efficacy while avoiding the side effects of conventional radical surgery. The purpose of this article is to review the existing literature regarding the basis of various focal therapy techniques such as cryotherapy, microwave, laser, and high intensity focused ultrasound, and to discuss the results of recent clinical trials that demonstrate early outcomes in patients with prostate cancer.

High-Intensity Focused Ultrasound (HIFU) in Localized Prostate Cancer Treatment

Background

High-intensity focused ultrasound (HIFU) applies high-intensity focused ultrasound energy to locally heat and destroy diseased or damaged tissue through ablation. This study intended to review HIFU to explain the fundamentals of HIFU, evaluate the evidence concerning the role of HIFU in the treatment of prostate cancer (PC), review the technologies used to perform HIFU and the published clinical literature regarding the procedure as a primary treatment for PC.

Material/Methods

Studies addressing HIFU in localized PC were identified in a search of internet scientific databases. The analysis of outcomes was limited to journal articles written in English and published between 2000 and 2013.

Results

HIFU is a non-invasive approach that uses a precisely delivered ultrasound energy to achieve tumor cell necrosis without radiation or surgical excision. In current urological oncology, HIFU is used clinically in the treatment of PC. Clinical research on HIFU therapy for localized PC began in the 1990s, and the majority of PC patients were treated with the Ablatherm device.

Conclusions

HIFU treatment for localized PC can be considered as an alternative minimally invasive therapeutic modality for patients who are not candidates for radical prostatectomy. Patients with lower pre-HIFU PSA level and favourable pathologic Gleason score seem to present better oncologic outcomes. Future advances in technology and safety will undoubtedly expand the HIFU role in this indication as more of patient series are published, with a longer follow-up period.

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.

Pelvic applications of MR-guided high intensity focused ultrasound

MR-guided high intensity focused ultrasound (MRg HIFU) is a novel method of tissue ablation that incorporates high energy focused ultrasound for tissue heating and necrosis within an MR scanner that provides simultaneous stereotactic tissue targeting and thermometry. To date, MRg HIFU has been used primarily to treat uterine fibroids, but many additional applications in the pelvis are in development. This article reviews the basic technology of MRg HIFU, and the use of MRg HIFU to treat uterine fibroids, adenomyosis, and prostate cancer.

Current approaches, challenges and future directions for monitoring treatment response in prostate cancer

Prostate cancer is the most commonly diagnosed non-cutaneous neoplasm in men in the United States and the second leading cause of cancer mortality. One in 7 men will be diagnosed with prostate cancer during their lifetime. As a result, monitoring treatment response is of vital importance. The cornerstone of current approaches in monitoring treatment response remains the prostate-specific antigen (PSA). However, with the limitations of PSA come challenges in our ability to monitor treatment success. Defining PSA response is different depending on the individual treatment rendered potentially making it difficult for those not trained in urologic oncology to understand. Furthermore, standard treatment response criteria do not apply to prostate cancer further complicating the issue of treatment response. Historically, prostate cancer has been difficult to image and no single modality has been consistently relied upon to measure treatment response. However, with newer imaging modalities and advances in our understanding and utilization of specific biomarkers, the future for monitoring treatment response in prostate cancer looks bright.

There is no role for focal therapy in prostate cancer

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Seven years of experience with high-intensity focused ultrasound for prostate cancer: advantages and limitations

BACKGROUND

The aim of this study was to evaluate oncologic outcomes and adverse events for patients with prostate cancer after treatment by high-intensity focused ultrasound (HIFU).

METHODS

Between February 2004 and August 2010, patients with prostate cancer who underwent HIFU treatment were reviewed about oncologic outcomes and complications. Biochemical recurrence (BCR) was defined as prostate-specific antigen (PSA) nadir plus 1.2 ng/ml. Kaplan-Meier analysis was performed to evaluate BCR- and disease progression-free survival according to risk stratification. Predictors for BCR and disease progression were identified using the Cox-proportional hazard method.

RESULTS

The overall BCR rate was 59.5%, and median time to BCR was 13.8 months. The 5-year BCR-free survival rates of the low-, intermediate-, and high-risk groups were 66.3, 40.2, and 21.0% (P = 0.001), respectively, and the 5-year disease progression-free survival rates were 73.5, 46.0, and 29.2%, respectively (P = 0.008). Multivariate analysis showed that risk stratification, PSA nadir, and time to PSA nadir were significant predictors of BCR and disease progression. In the first 3 months post-op, 11 patients (8.7%) had complications. There were no patients who required blood transfusions or who had wound problems, stroke, deep vein thrombosis, or bowel dysfunction.

CONCLUSIONS

HIFU treatment does not provide effective oncologic outcomes even in low risk patients with prostate cancer as well as in the intermediate or high risk groups. Therefore, patients selected to undergo HIFU treatment for prostate cancer must be very carefully chosen. On the other hand, HIFU treatment for prostate cancer had a very low rate of complications.

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.

Preliminary safety and efficacy results with robotic high-intensity focused ultrasound : A single center Indian experience

Background:

There are no Indian data of high-intensity focused ultrasound (HIFU). Being an alternative, still experimental modality, reporting short-term safety outcome is paramount.

Aims:

This study was aimed at to assess the safety and short-term outcome in patients with prostate cancer treated by HIFU.

Settings and Design:

A retrospective study of case records of 30 patients undergoing HIFU between January 2008 to September 2010 was designed and conducted.

Materials and Methods:

The procedural safety was analyzed at 3 months. Follow-up consisted of 3 monthly prostate-specific antigen (PSA) levels and transrectal biopsy if indicated. All the patients had a minimum follow-up of 6 months.

Results:

A mean prostate volume of 26.9 ± 8.5 cm³ was treated in a mean time of 115 ± 37.4 min. There was no intraoperative complication. The postoperative pain visual analogue score at day 0 was 2.1 ± 1.9 and at day 1 was 0.4 ± 0.8 on a scale of 1-10. Mean duration of perurethral catheter removal was 3.9 days. The complications after treatment were: LUTS in seven patients, stress incontinence in two, stricture in two, and symptomatic urinary tract infection in five. Average follow-up duration was 10.4 months (range, 6-20 months). Mean time to obtain PSA nadir was 6 ± 3 months with a median PSA nadir value of 0.3 ng/ml. Two patients had positive prostatic biopsy in the localized (high risk) group.

Conclusions:

HIFU was safe in carcinoma prostate patients. The short-term results were efficacious in localized disease. The low complication rates and favorable functional outcome support the planning of further larger studies.

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.

High intensity focused ultrasound in clinical tumor ablation

Recent advances in high intensity focused ultrasound (HIFU), which was developed in the 1940s as a viable thermal tissue ablation approach, have increased its popularity. In clinics, HIFU has been applied to treat a variety of solid malignant tumors in a well-defined volume, including the pancreas, liver, prostate, breast, uterine fibroids, and soft-tissue sarcomas. In comparison to conventional tumor/cancer treatment modalities, such as open surgery, radio- and chemo-therapy, HIFU has the advantages of non-invasion, non-ionization, and fewer complications after treatment. Over 100 000 cases have been treated throughout the world with great success. The fundamental principles of HIFU ablation are coagulative thermal necrosis due to the absorption of ultrasound energy during transmission in tissue and the induced cavitation damage. This paper reviews the clinical outcomes of HIFU ablation for applicable cancers, and then summarizes the recommendations for a satisfactory HIFU treatment according to clinical experience. In addition, the current challenges in HIFU for engineers and physicians are also included. More recent horizons have broadened the application of HIFU in tumor treatment, such as HIFU-mediated drug delivery, vessel occlusion, and soft tissue erosion (“histotripsy”). In summary, HIFU is likely to play a significant role in the future oncology practice.

Minimally invasive ablative therapies for definitive treatment of localized prostate cancer in the primary setting

Traditionally, the patient with a new diagnosis of localized prostate cancer faces either radical therapy, in the form of surgery or radiation, or active surveillance. A growing subset of these men may not be willing to accept the psychological burden of active surveillance nor the side effects of extirpative or radiation therapy. Local ablative therapies including cryotherapy, high-intensity focused ultrasound, and vascular-targeted photodynamic therapy have emerged as a means for minimally invasive definitive treatment. These treatments are well tolerated with decreased morbidity in association with improvements in technology; however, long-term oncologic efficacy remains to be determined.

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.

Systematic review of the efficacy and safety of high-intensity focussed ultrasound for the primary and salvage treatment of prostate cancer

CONTEXT

High-intensity focussed ultrasound (HIFU) is an emerging minimally invasive treatment option for prostate cancer.

OBJECTIVE

Our aim was to assess the efficacy and safety of HIFU in both primary treatment of men with localised and locally advanced prostate cancer as well as salvage treatment of men with recurrent prostate cancer following treatment failure of radical prostatectomy or external-beam radiation therapy.

EVIDENCE ACQUISITION

We conducted a systematic literature search for studies conducted on humans and published in either English or German in several databases from 2000 to 2010. In addition, we screened several Web sites for assessments on HIFU in prostate cancer and contacted the manufacturers of the two currently available HIFU devices for supplemental information on HIFU. We included all prospective studies with >50 study participants and assessed their quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

EVIDENCE SYNTHESIS

We identified 20 uncontrolled prospective case series, each of which treated between 58 and 517 patients. These studies were all conducted within the past decade. In total, 3018 patients were treated with HIFU, 93% for primary therapy and 7% for salvage HIFU. For all HIFU procedures, the biochemical disease-free survival rate at 1, 5, and 7 yr, respectively, was 78-84%, 45-84%, and 69%. The negative biopsy rate was 86% at 3 mo and 80% at 15 mo. Overall survival rates and prostate cancer-specific survival rates were 90% and 100% at 5 yr and 83% and 98% at 8 yr, respectively. Adverse events concerned the urinary tract (1-58%), potency (1-77%), the rectum (0-15%), and pain (1-6%). Quality-of-life assessment yielded controversial results.

CONCLUSIONS

Applying the GRADE approach, the available evidence on efficacy and safety of HIFU in prostate cancer is of very low quality, mainly due to study designs that lack control groups. More research is needed to explore the use of HIFU in prostate cancer.

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 and prostate cancer: technology, state of the art and future

Background.

The potential applications of the high-intensity focused ultrasound (HIFU) as a minimally invasive therapy of the localized prostate cancer explain the growing interest of the urologic community towards this technique. HIFU has been assessed for its role in the treatment of localized prostate cancer in patients who otherwise would not have benefited from surgery, and in local recurrences after radiation failure.

Methods.

Relevant information on HIFU treatment was identified through a literature search of published studies.

Results.

High biochemical efficacy, excellent tumor local control and favorable mid- and long-term oncological data with a low morbidity rate have been shown in many series of patients.

Conclusions.

Although HIFU is a recent and emerging technology, it has been well studied and developed to a point that HIFU will undoubtedly be an effective alternative to radiation therapy.

High-intensity focused ultrasound in prostate cancer; a systematic literature review of the French Association of Urology

We discuss the efficacy and safety of high-intensity focused ultrasound (HIFU) in patients with prostate cancer, to define the best indications for HIFU in daily clinical practice as primary therapy. We searched Medline and Embase for clinical studies evaluating the efficacy and safety of HIFU in prostate cancer (July 2007), and abstracts presented at the 2005-2007 annual meetings of the European Association of Urology and American Urological Association were screened. In all, 37 articles/abstracts were selected. As the data on HIFU as salvage therapy were limited, we focused on HIFU as primary therapy. Studies consisted of case series only. Included patients were approximately 70 years old with T1-T2 N0M0 disease, Gleason Score <or=7, a prostate-specific antigen (PSA) level of <or=28 ng/mL and a prostate volume of <or=40 mL. Negative biopsy rates with the Ablatherm device (EDAP TMS S.A., Vaulx-en-Velin, France) were 64-93%, and a PSA nadir of <or=0.5 ng/mL was achieved in 55-84% of patients. The 5-year actuarial disease-free survival rates were 60-70%. The most common complications were stress urinary incontinence, urinary tract infection, urethral/bladder neck stenosis or strictures, and erectile dysfunction. For the Ablatherm device, the rate of complications has been significantly reduced over the years, due to technical improvements in the device and the use of transurethral resection of the prostate before HIFU. In conclusion, HIFU as primary therapy for prostate cancer is indicated in older patients (>or=70 years) with T1-T2 N0M0 disease, a Gleason score of <7, a PSA level of <15 ng/mL and a prostate volume of <40 mL. In these patients HIFU achieves short-term cancer control, as shown by a high percentage of negative biopsies and significantly reduced PSA levels. The median-term survival data also seem promising, but long-term follow-up studies are needed to further evaluate cancer-specific and overall survival rates before the indications for primary therapy can be expanded.

High-intensity focused ultrasound: current potential and oncologic applications

OBJECTIVE

The objective of this article is to introduce the reader to the principles and applications of high-intensity focused ultrasound (HIFU).

CONCLUSION

Although a great deal about HIFU physics is understood, its clinical applications are currently limited, and multiple trials are underway worldwide to determine its efficacy.