Oncologic outcome, side effects and comorbidity of high-intensity focused ultrasound (HIFU) for localized prostate cancer. A review

High-Intensity Focused Ultrasound (Sonablate®) for Prostate Cancer: Preliminary Outcomes in Taiwan

PURPOSE

We reported preliminary outcomes of high-intensity focused ultrasound (HIFU) [Sonablate®] in the combination of transurethral resection of the prostate for localized prostate cancer in Taiwan.

METHODS

Seventy-seven patients using Sonablate® HIFU for localized prostate cancer were enrolled in this study from April 2021 to December 2022. Prostate-specific antigen biochemical recurrence, International Index of Erectile Function (IIEF)-5 scores, International Prostate Symptom Score (IPSS), quality of life (QoL) scores, and postoperative complications were recorded during follow-up.

RESULTS

Overall, 19.5% of patients were low-risk, 36.4% were intermediate-risk, and 44.1% were high-risk according to the D'Amico risk classification. The median follow-up was 12.09 ± 5.85 months, and the biochemical-free survival rates for the low-, intermediate-, and high-risk groups were 100% (15/15), 96.4% (27/28), and 79.4% (27/34), respectively. Four patients (5.2%) received salvage radiotherapy and all maintained biochemical-free survival. The mean IPSS and QoL scores before versus after HIFU were 10.4 versus 6.8 (p = 0.003) and 3.2 versus 3.0 (p = 0.096), respectively. There was no statistically significant change in preoperative and postoperative IIEF scores (20.6 vs. 19; p = 0.062) in patients who had an IIEF score of >15 at baseline and received nerve-sparing procedures (subtotal ablation).

CONCLUSIONS

The results of Sonablate® HIFU in Taiwan indicated adequate short-term cancer control, excellent potency, and continence preservation. HIFU can achieve improvement of IPSS with low complication rates.

Biopsy and Erectile Functional Outcomes of Partial Prostate Ablation: A Systematic Review and Meta-analysis of Prospective Studies

OBJECTIVE

To provide a systematic summary of prospectively performed studies evaluating ablative therapies for the treatment of prostate cancer (PCa) that included protocol-mandated assessment of (1) residual disease by post-treatment biopsy and/or (2) erectile functional outcomes.

MATERIALS AND METHODS

We performed a comprehensive literature search in September 2022. Studies were evaluated according to a predefined and registered plan in PROSPERO (CRD42022302777). Only prospective trials with protocol-mandated post-treatment prostate biopsies or functional assessments were included. Targeted focal therapy was the only ablation pattern with sufficient data to perform meta-analyses (29 studies, 1079 patients).

RESULTS

At baseline, 65.0% of patients treated with targeted focal therapy harbored grade group (GG) ≥2 PCa. One year after treatment, in-field treatment failure with ≥GG1 and ≥GG2 PCa occurred in 25.7% (range 11.1%-66.7%) and 8.8% (range 0%-27.8%) of men, respectively. In patients that received whole-gland biopsies 1year after ablation, residual ≥GG1 and ≥GG2 PCa was detected anywhere in the prostate in 43.7% (range 19.4%-71.7%) and 13.0% (range 0%-35.9%) of men. Erectile function was negatively affected by treatment, but 78.7% were potent 1year after targeted focal therapy (7 studies, 197 patients), and the average decrease in erectile function scores was 8.8% at 1year (21 studies, 760 patients).

CONCLUSION

Though long-term data after targeted focal therapy are limited, oncologic and treatment failure occurred in 13% and 9% (≥GG2 at 6-12months after treatment). Most men were able to maintain potency. This work can help benchmark new techniques and power future trials.

On-demand regulation and enhancement of the nucleation in acoustic droplet vaporization using dual-frequency focused ultrasound

Acoustic droplet vaporization (ADV) plays an important role in focused ultrasound theranostics. Better understanding of the relationship between the ultrasound parameters and the ADV nucleation could provide an on-demand regulation and enhancement of ADV for improved treatment outcome. In this work, ADV nucleation was performed in a dual-frequency focused ultrasound configuration that consisted of a continuous low-frequency ultrasound and a short high-frequency pulse. The combination was modelled to investigate the effects of the driving frequency and acoustic power on the nucleation rate, efficiency, onset time, and dimensions of the nucleation region. The results showed that the inclusion of short pulsed high-frequency ultrasound significantly increased the nucleation rate with less energy, reduced the nucleation onset time, and changed the length-width ratio of the nucleation region, indicating the dual-frequency ultrasound mode yields an efficient enhancement of the ADV nucleation, compared to a single-frequency ultrasound mode. Furthermore, the acoustic and temperature fields varied independently with the dual-frequency ultrasound parameters. This facilitated the spatial and temporal control over the ADV nucleation, and opens the door to the possibility to realize on-demand regulation of the ADV occurrence in ultrasound theranostics. In addition, the improved energy efficacy that is obtained with the dual-frequency configuration lowered the requirements on hardware system, increasing its flexibility and could facilitate its implementation in practical applications.

Ultrasound-induced cavitation and passive acoustic mapping: SonoTran platform performance and short-term safety in a large-animal model

Ultrasound-induced cavitation is currently under investigation for several potential applications in cancer treatment. Among these, the use of low-intensity ultrasound, coupled with the systemic administration of various cavitation nuclei, has been found to enhance the delivery of co-administered therapeutics into solid tumors. Effective pharmacological treatment of solid tumors is often hampered, among various factors, by the limited diffusion of drugs from the bloodstream into the neoplastic mass and through it, and SonoTran holds the potential to tackle this clinical limitation by increasing the amount of drug and its distribution within the ultrasound-targeted tumor tissue. Here we use a clinically ready system (SonoTran Platform) composed of a dedicated ultrasound device (SonoTran System) capable of instigating, detecting and displaying cavitation events in real time by passive acoustic mapping and associated cavitation nuclei (SonoTran Particles), to instigate cavitation in target tissues and illustrate its performance and safety in a large-animal model. This study found that cavitation can be safely triggered and mapped at different tissue depths and in different organs. No adverse effects were associated with infusion of SonoTran Particles, and ultrasound-induced cavitation caused no tissue damage in clinically targetable organs (e.g., liver) for up to 1 h. These data provide evidence of cavitation initiation and monitoring performance of the SonoTran System and the safety of controlled cavitation in a large-animal model using a clinic-ready platform technology.

A review of high-intensity focused ultrasound as a novel and non-invasive interventional radiology technique

High-intensity focused ultrasound (HIFU) is a non-invasive interventional radiology technology, which has been generally accepted in clinical practice for the treatment of benign and malignant tumors. HIFU can cause targeted tissue coagulative necrosis and protein denaturation by thermal or non-thermal effects, guided by diagnostic ultrasound or magnetic resonance imaging, without destruction of the normal adjacent tissue, under sedation or general anesthesia. HIFU has become an important alternative to standard treatments of solid tumors, including surgery, radiation, and medications. The aim of this review is to describe the development, principle, devices, and clinical applications of HIFU.

Low-Power Magnetic Resonance-Guided Focused Ultrasound Tumor Ablation upon Controlled Accumulation of Magnetic Nanoparticles by Cascade-Activated DNA Cross-Linkers

Magnetic resonance-guided focused ultrasound (MRgFUS) is a promising non-invasive surgical technique with spatial specificity and minimal off-target effects. Despite the expanding clinical applications, the major obstacles associated with MRgFUS still lie in low magnetic resonance imaging (MRI) sensitivity and safety issues. High ultrasound power is required to resist the energy attenuation during the delivery to the tumor site and may cause damage to the surrounding healthy tissues. Herein, a surface modification strategy is developed to simultaneously strengthen MRI and ultrasound ablation of MRgFUS by prolonging Fe₃O₄ nanoparticles' blood circulation and tumor-environment-triggered accumulation and retention at the tumor site. Specifically, reactive oxygen species-labile methoxy polyethylene glycol and pH-responsive DNA cross-linkers are modified on the surface of Fe₃O₄ nanoparticles, which can transform nanoparticles into aggregations through the cascade responsive reactions at the tumor site. Notably, DNA is selected as the pH-responsive cross-linker because of its superior biocompatibility as well as the fast and sensitive response to the weak acidity of 6.5-6.8, corresponding to the extracellular pH of tumor tissues. Due to the significantly enhanced delivery and retention amount of Fe₃O₄ nanoparticles at the tumor site, the MRI sensitivity was enhanced by 1.7-fold. In addition, the ultrasound power was lowered by 35% to reach a sufficient thermal ablation effect. Overall, this investigation demonstrates a feasible resolution to promote the MRgFUS treatment by enhancing the therapeutic efficacy and reducing the side effects, which will be helpful to guide the clinical practice in the future.

Locoregional therapies and their effects on the tumoral microenvironment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is expected to become the second leading cause of death from cancer by 2030. Despite intensive research in the field of therapeutics, the 5-year overall survival is approximately 8%, with only 20% of patients eligible for surgery at the time of diagnosis. The tumoral microenvironment (TME) of the PDAC is one of the main causes for resistance to antitumoral treatments due to the presence of tumor vasculature, stroma, and a modified immune response. The TME of PDAC is characterized by high stiffness due to fibrosis, with hypo microvascular perfusion, along with an immunosuppressive environment that constitutes a barrier to effective antitumoral treatment. While systemic therapies often produce severe side effects that can alter patients' quality of life, locoregional therapies have gained attention since their action is localized to the pancreas and can thus alleviate some of the barriers to effective antitumoral treatment due to their physical effects. Local hyperthermia using radiofrequency ablation and radiation therapy - most commonly using a local high single dose - are the two main modalities holding promise for clinical efficacy. Recently, irreversible electroporation and focused ultrasound-derived cavitation have gained increasing attention. To date, most of the data are limited to preclinical studies, but ongoing clinical trials may help better define the role of these locoregional therapies in the management of PDAC patients.

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.

Percutaneous Radiofrequency Ablation (RFA) in renal cancer. How to manage challenging masses. A narrative review

In the last decades, the refinements in the imaging techniques led to an increased number of detected renal tumors. If radical and partial nephrectomy remain the gold standard for the treatment of renal cancer, Radio-Frequency Ablation (RFA) has emerged as a therapeutic option for renal masses. Even if this technique is minimally-invasive, it requires a proper preoperative anatomic study and in some cases RFA treatment is technically challenging. To date, there is no standardization for studying challenging cases before treatment and to plan a safe and effective procedure when intervening organs are in the trajectory of the needle. In this study we searched the literature focusing on the challenging cases and strategy applied to manage the treatment safely and effectively.

MATERIALS AND METHODS

MedLine and Embase via Ovid database were searched, using the following key words: Percutaneous RFA, radiofrequency, renal ablation, kidney ablation, renal thermoablation, kidney thermoablation, hydrodissection, heat sink. The difficulties found in the literature while performing the ablation procedure were grouped and a categorization of the strategies applied to perform a safe and effective procedure was proposed, in the aim to standardize the approach for treatment of challenging cases. Literature was analyzed according with selection criteria agreed by the Authors.

RESULTS

The literature review showed four groups of lesions requiring an experienced approach. Group 1: Lesions close to the bowel. Group 2: Lesions close to the urinary tract. Group 3: Lesions close to intervening organs. Group 4: Lesions close to large vessels (heat-sink phenomenon).

CONCLUSION

When planning a RFA treatment, a standardized approach to challenging masses is possible. This review make the treatment of these masses more systematic and safe.

Oncological and functional outcome after partial prostate HIFU ablation with Focal-One®: a prospective single-center study

BACKGROUND

We aimed to evaluate oncological and functional outcomes of index lesion HIFU ablation with Focal-One^®.

MATERIALS AND METHODS

We prospectively assessed treatment-naïve men with localized prostate cancer between 2017 and 2019. Inclusion criteria were stage cT ≤ 2, ≥5 years of life expectancy, grade group ≤3. Multiparametric magnetic resonance was performed before ablation. Patients with a prostate volume of ≥80 ml underwent debulking. Treatment failure was defined as a histologically confirmed tumor that required salvage treatment or androgen deprivation therapy.

RESULTS

One hundred and eighty nine patients were enrolled. Data are presented as median and Interquartile Range (IQR). Median age was 70(11) years. Median baseline PSA was 5.8(3) ng/ml. Fourteen (7.4%) patients had prostate debulking before ablation. 104 (55%) patients underwent targeted ablation, 45 (23.8%) extended targeted ablation, 31 (16.4%) hemiablation, and 9 (4.8%) extended hemiablation. Median targeted ablated volume was 14(9) ml. Ninety-three complications occurred in 63/189 (33.3%) patients within 90 days. There were 77/93 (82.8%) minor (Clavien grade 1-2) and 16/93 (17.2%) major complications (Clavien grade 3a). Thirty-nine patients suffered from genito-urinary infections (Clavien grade 2). Fifteen patients required transurethral resection of the prostate/urethrotomy for recurrent urinary retention (Clavien grade 3a). One patient developed a recto-urethral fistula (Clavien grade 3a) and two long-lasting urinary incontinence. Median PSA nadir was 2.2(2.9) ng/ml. At a median follow-up of 29(15) months, 21/177 (11.9%) patients were treatment failures, 26 on monitoring, and 26 had a further ablation. Multivariable logistic regression found that failure patients had higher PSA (7.8 vs 5.7 ng/ml,p0.001) and double PSA nadir (4.8 vs 2.0 ng/ml, p < 0.001). Higher PSA nadir correlated with a 74% higher probability of failure (OR 1.74 95% CI 1.40-2.16). Cancer in the anterior stroma increased the odds of failure of three folds (OR 3.36 95% CI 1.18-9.53). Two mixed effect models (one for IPSS and one for IEEF-15) were estimated and they showed that time reaches the statistical significance coefficient only for the IEEF-15, meaning that subsequent evaluations of the indicators were significantly lower at each time point.

CONCLUSIONS

Index lesion HIFU ablation demonstrated satisfactory early oncological outcome but anteriorly located tumors had inadequate ablation. Urinary function was well preserved. Sexual function slightly decreased during follow-up.

Oncologic outcome of salvage high-intensity focused ultrasound (HIFU) in radiorecurrent prostate cancer. A systematic review

INTRODUCTION

External Beam Radiation Therapy (EBRT) is one of the option available for the treatment of clinically localized prostate cancer. In patients with radiorecurrent localized prostate cancer, Androgen Deprivation Therapy (ADT) is one of the most common therapeutic strategies. However, in the last decades, other salvage treatment options have been investigated, such as brachytherapy, cryoablation and High Intensity Focused Ultrasound (Hifu).

MATERIAL AND METHODS

The oncologic outcome of Hifu in a salvage setting after EBRT failure was investigated. We reviewed the literature from 2005 to 2020 in order to report the oncologic outcome of the technique.

RESULTS

A total of 1241 patients were analyzed, with a mean age of 68.6 years and a PSA value of 5.87 ng/mL before treatment. Mean follow-up was 24.3 months after treatment, ranging from 3 to 168 months.

CONCLUSION

Our review of the literature revealed that salvage Hifu is effective in the treatment of radiorecurrent clinically localized prostate cancer, with an overall survival of 85.2% at 5 years.

Potential Alternatives to Conventional Cancer Therapeutic Approaches: The Way Forward

onventional cancer therapeutic approaches broadly include chemotherapy, radiation therapy and surgery. These established approaches have evolved over several decades of clinical experience. For a complex disease like cancer, satisfactory treatment remains an enigma for the simple fact that the causal factors for cancer are extremely diverse. In order to overcome existing therapeutic limitations, consistent scientific endeavors have evolved several potential therapeutic approaches, majority of which focuses essentially on targeted drug delivery, minimal concomitant ramification, and selective high cytotoxicity. The current review focuses on highlighting some of these potential alternatives that are currently in various stages of in vitro, in vivo, and clinical trials. These include physical, chemical and biological entities that are avidly being explored for therapeutic alternatives. Some of these entities include suicide gene, micro RNA, modulatory peptides, ultrasonic waves, free radicals, nanoparticles, phytochemicals, and gene knockout, and stem cells. Each of these techniques may be exploited exclusively and in combination with conventional therapeutic approaches thereby enhancing the therapeutic efficacy of the treatment. The review intends to briefly discuss the mechanism of action, pros, and cons of potential alternatives to conventional therapeutic approaches.

Oncologic outcome of salvage high-intensity focused ultrasound (HIFU) in radiorecurrent prostate cancer. A systematic review

INTRODUCTION

External Beam Radiation Therapy (EBRT) is one of the option available for the treatment of clinically localized prostate cancer. In patients with radiorecurrent localized prostate cancer, Androgen Deprivation Therapy (ADT) is one of the most common therapeutic strategies. However, in the last decades, other salvage treatment options have been investigated, such as brachytherapy, cryoablation and High Intensity Focused Ultrasound (Hifu).

MATERIAL AND METHODS

The oncologic outcome of Hifu in a salvage setting after EBRT failure was investigated. We reviewed the literature from 2005 to 2020 in order to report the oncologic outcome of the technique.

RESULTS

A total of 1241 patients were analyzed, with a mean age of 68.6 years and a PSA value of 5.87 ng/mL before treatment. Mean follow-up was 24.3 months after treatment, ranging from 3 to 168 months.

CONCLUSION

Our review of the literature revealed that salvage Hifu is effective in the treatment of radiorecurrent clinically localized prostate cancer, with an overall survival of 85.2% at 5 years.