Ablation energies for focal treatment of prostate cancer

Cellular level cryo-neuromodulation using rapid and localized cooling device combined with microelectrode array

Cryotherapy, a rapid and effective medical treatment utilizing low temperatures, has not been widely adopted in clinical practice due to a limited understanding of its mechanisms and efficacy. This challenge stems from the absence of methods for fast, precise, and localized spatiotemporal temperature control, as well as the lack of reliable real-time quantitative techniques for measuring and analyzing the effects of cooling. To address these limitations, this study introduces a cryo-neuromodulation platform that integrates a high-speed precision cooling device with a microelectrode array (MEA) system. This platform enables the investigation of cellular-level cryo-modulation of neuronal activity and its effects on surrounding cells, providing a novel framework for advancing research in cryotherapy and neuromodulation. Experiments show that neurons recovered fully within 1 min of cooling with a fast-cooling rate (-20 °C/s at cooling) and that silenced neurons can influence distant cells via a well-organized network. Extended cooling durations (e.g., 10 min) resulted in altered neuronal dynamics, including delayed recovery and reduced burst activity, highlighting the importance of precise control over cooling parameters. This device offers reversible neural control, with potential applications in both research and clinical settings, such as anesthesia, pain management and treatment of neurological disorders like neocortical seizures.

Medium-Term Outcomes after Primary Whole-Gland High-Intensity Focused Ultrasound Ablation for the Treatment of Prostate Cancer: A Single-Center Experience

Objectives: Our aim was to assess the oncologic and functional outcomes of primary whole-gland high-intensity focused ultrasound (WG-HIFU) treatment for non-metastatic prostate cancer (PCa). Patients and Methods: We retrospectively analyzed data from 227 men treated with WG-HIFU at a single center between 2011 and 2019. Patients with prostate-specific antigen (PSA) greater than 20 ng/mL, positive nodes, or missing data were excluded. Primary outcome was failure-free survival (FFS). Failure was defined as any recurrence requiring salvage radical or systemic treatment, metastasis, or PCa-specific death. Results: The median follow-up was of 47 months. FFS rates at 1, 3, and 5 years were 97%, 82%, and 75%, respectively. The 5-year FFS rates were 91%, 78%, and 59% for the low-, intermediate-, and high-risk patients, respectively. The 5-year metastasis-free survival and cancer-specific survival rates were 93% and 97%, respectively. The overall pad-free continence and social continence rates were 83% and 95%, respectively. Approximately 62% of previously potent patients undergoing WG-HIFU maintained erections sufficient for penetration. Bilateral nerve-sparing (NS) improved functional outcomes, with 68.6% achieving sufficient erections and 89.6% achieving pad-free continence. Clavien-Dindo grade 3 complications occurred in 22%. Higher PSA, clinical T stage, biopsy grade group, and nadir PSA levels were independently associated with treatment failure. Conclusion: WG-HIFU combined with transurethral resection of the prostate provides good medium-term oncologic control in appropriately selected patients and tolerable results in terms of genitourinary toxicity. Bilateral NS was associated with better urinary and erectile function.

Advancements in high-intensity focused ultrasound for urological tumor research and application

High-intensity focused ultrasound (HIFU), a non-invasive therapeutic approach, has made significant inroads in urological oncology, notably for kidney, bladder, and prostate cancers. Its advantages in treating prostate cancer are particularly pronounced, offering less invasive treatment with faster recovery and superior organ function preservation compared to traditional methods. HIFU is an advantageous option for patients with localized prostate cancer who prefer nonsurgical treatments or have a high demand for quality of life. Despite its benefits, HIFU faces limitations requiring further research and clinical validation to ensure safety and effectiveness. This paper provides a concise review of HIFU's current application in urological tumor treatment, highlighting its role in prostate cancer therapy and exploring its potential in the adjuvant treatment of advanced prostate cancer, offering insights for its future role in urological oncology.

Focal therapy for prostate cancer

Traditional treatments for localized prostate cancer include radical prostatectomy or radiation therapy but pose challenges due to treatment related side effects, namely erectile dysfunction and urinary incontinence. In recent years, focal therapy has emerged as a viable treatment option for localized low-intermediate risk prostate cancer in carefully selected patients. Short and medium-term studies show acceptable cancer control outcomes and reduced morbidity when comparing focal therapy to whole gland treatment for prostate cancer, however there is paucity of long-term studies. Here we review focal ablative therapies commonly used, discuss the role of imaging in monitoring treatment, and summarize oncologic outcomes based on studies to date.

Current role of focal therapy in prostate cancer

BACKGROUND

Thanks to the improved accuracy of multiparametric Magnetic Resonance Imaging (mpMRI) to detect and localize the dominant index lesion on prostate cancer (PCa), the concept of minimally invasive focal treatments (FT) has gained popularity. Nevertheless, although high-quality evidence that FT has favorable functional outcomes, definitive proof of its oncological effectiveness compared to standard treatments remains underreported.

OBJECTIVE

This study aims to explore the efficacy, safety, oncologic and functional outcomes of different type of FT for PCa.

EVIDENCE ACQUISITION

A non-systematic literature review was conducted by searching on PubMed "prostate cancer" AND "focal treatment" OR "HIFU" OR "irreversible electroporation" OR "cryoablation" OR "focal laser ablation." Overall, 22 articles published in English literature from 2018 to 2023 describing FT techniques for PCa were included.

EVIDENCE SYNTHESIS

Related to the field ablated, focal therapies include hemiablation (half gland), focal ablation (zonal-base) or targeted therapy (lesion-based). FT modalities can be categorized in thermal and non-thermal energy: thermal energy techniques include high-intensity focused ultrasound (HIFU), cryotherapy, radiofrequency ablation (RFA), and focal laser ablation (FLA). Focal brachytherapy, irreversible electroporation (IRE), and vascular-targeted photodynamic therapy (VTP) are classified as non-thermal ablation. Each focal ablative treatments could be promising alternative to conventional radical therapies to treat PCa in term of mid-term oncologic and functional outcomes, however, limited data are available in comparison with standardized radical treatments. HIFU and Cryo are the most studied techniques and seem to be superior to radical treatments in term of functional outcomes despite associated with higher recurrence and retreatment rate.

CONCLUSIONS

Current evidences of oncologic and functional outcomes of FT are based mainly on retrospective, non-comparative and single center studies. Thus, none of the focal therapies available should be considered safe alternative to standardized treatments in routine practice and should be offered only for well selected PCa patients with low or at least favorable-intermediate risk disease, unfit for radical options.

Real-World Safety of Prostate Cancer Focal Therapy: MAUDE Database Analysis

Objective: The aim of this study was to assess the real-world safety profile of medical devices used in focal prostate cancer treatment utilizing the Manufacturer and User Facility Device Experience (MAUDE) database. Methods: The MAUDE database was searched for reports on high-intensity focused ultrasound (HIFU), cryoablation, laser ablation, and irreversible electroporation (IRE) devices used in prostate cancer treatment from 1993 to 2023. Adverse events were identified and categorized. Results: We identified 175 reports for HIFU, 1362 for cryoablation, 615 for laser ablation, and 135 for IRE devices, with 28, 284, 126, and 2 respective reports, directly related to prostate cancer treatment. The aggregated data revealed the majority of complications were minor, with 82.5% (n = 363 out of 440 total complications) classified as Clavien-Dindo grade 1 or 2. Common minor complications included erectile dysfunction and urinary retention. Severe complications such as rectal fistulas were noted in HIFU and IRE treatments, along with singular mortality due to pulmonary embolism in cryoablation. Conclusions: Our analyses from MAUDE reveal that devices used in focal therapy for prostate cancer are predominantly associated with minor complications, underscoring their overall real-world safety profile. However, the occurrence of severe adverse events emphasizes the critical importance of rigorous patient selection and meticulous procedural planning. These findings provide valuable insights into the safety profile of focal therapy devices and contribute to the growing body of evidence on their use in prostate cancer treatment.

Effect of Acoustically Responsive Droplet-based Low-intensity Histotripsy on Canine Prostate

OBJECTIVE

Low-intensity histotripsy (LIH) is a novel and safe technique for tissue ablation. This study aimed to explore the effects of LIH on canine prostate tissue and identify the degree of acute injury to the gland.

METHODS

We constructed and evaluated two types of acoustically responsive droplet (ARD) emulsions using either perfluoropentane (PFP) with a lipid shell or perfluoromethyl-cyclopentane (PFMCP) with lauromacrogol (L) injection. Twenty beagles were assigned to four experimental groups: ultrasound (US) + PFP (n = 6), US + PFMCP-L (n = 6), PFMCP-L (n = 5) and PFP (n = 3). The ARDs were injected transcutaneously and transabdominally into normal canine prostates under US-guided imaging. Subsequently, focused therapeutic US was employed to induce acoustic droplet vaporization and bubble cloud cavitation. The mechanical damage to canine prostate tissue was evaluated using gross and histological examination.

RESULTS

Gross specimens showed that the injured area was dark brown. Hematoxylin and eosin-stained tissue sections of the damage zone showed significant cavity formation and interstitial edema. The total tissue damage scores in the US + PFP group were compared to those of the other three experimental groups. No statistically significant differences were observed in the extent of tissue damage and total scores among the US + PFMCP-L, PFMCP-L and PFP groups.

CONCLUSION

We achieved significant mechanical tissue damage in the canine prostate using PFP ARD-based LIH that proved to be superior to that using PFMCP ARDs with LIH.

Design and evaluation of a pneumatic actuation unit for a wasp-inspired self-propelled needle

Transperineal laser ablation is a minimally invasive thermo-ablative treatment for prostate cancer that requires the insertion of a needle for accurate optical fiber positioning. Needle insertion in soft tissues may cause tissue motion and deformation, resulting in tissue damage and needle positioning errors. In this study, we present a wasp-inspired self-propelled needle that uses pneumatic actuation to move forward with zero external push force, thus avoiding large tissue motion and deformation. The needle consists of six parallel 0.25-mm diameter Nitinol rods driven by a pneumatic actuation system. The pneumatic actuation system consists of Magnetic Resonance (MR) safe 3D-printed parts and off-the-shelf plastic screws. A self-propelled motion is achieved by advancing the needle segments one by one, followed by retracting them simultaneously. The advancing needle segment has to overcome a cutting and friction force, while the stationary needle segments experience a friction force in the opposite direction. The needle self-propels through the tissue when the friction force of the five stationary needle segments overcomes the sum of the friction and cutting forces of the advancing needle segment. We evaluated the prototype's performance in 10-wt% gelatin phantoms and ex vivo porcine liver tissue inside a preclinical Magnetic Resonance Imaging (MRI) scanner in terms of the slip ratio of the needle with respect to the phantom or liver tissue. Our results demonstrated that the needle was able to self-propel through the phantom and liver tissue with slip ratios of 0.912-0.955 and 0.88, respectively. The prototype is a promising step toward the development of self-propelled needles for MRI-guided transperineal laser ablation as a method to treat prostate cancer.

Abdominal Wall Hernias Following High-intensity Focused Ultrasound Therapy: Three Case Reports

Although many studies reported the safety and efficacy of high-intensity focused ultrasound (HIFU) therapy, there are still worries about internal organ injury. However, reports of abdominal wall hernias after HIFU therapy are rare. We present three cases of abdominal wall hernias without skin injury after HIFU therapy in uterine adenomyosis or fibroids. The diagnosis was often delayed because of vague symptoms, inadequate clinical suspicion, and delayed proper image studies. Abdominal wall hernia should be recognized as a possible complication after HIFU and be suspected when the patient presents with unordinary abdominal swelling and/or pain that lasts for more than a few months after the procedure.

Therapeutic prostate cancer interventions: a systematic review on pubic arch interference and needle positioning errors

INTRODUCTION

This study focuses on the quantification of and current guidelines on the hazards related to needle positioning in prostate cancer treatment: (1) access restrictions to the prostate gland by the pubic arch, so-called Pubic Arch Interference (PAI) and (2) needle positioning errors. Next, we propose solution strategies to mitigate these hazards.

METHODS

The literature search was executed in the Embase, Medline ALL, Web of Science Core Collection*, and Cochrane Central Register of Controlled Trials databases.

RESULTS

The literature search resulted in 50 included articles. PAI was reported in patients with various prostate volumes. The level of reported PAI varied between 0 and 22.3 mm, depending on the patient's position and the measuring method. Low-Dose-Rate Brachytherapy induced the largest reported misplacement errors, especially in the cranio-caudal direction (up to 10 mm) and the largest displacement errors were reported for High-Dose-Rate Brachytherapy in the cranio-caudal direction (up to 47 mm), generally increasing over time.

CONCLUSIONS

Current clinical guidelines related to prostate volume, needle positioning accuracy, and maximum allowable PAI are ambiguous, and compliance in the clinical setting differs between institutions. Solutions, such as steerable needles, assist in mitigating the hazards and potentially allow the physician to proceed with the procedure.This systematic review was performed in accordance with the PRISMA guidelines. The review was registered at Protocols.io (DOI: dx.doi.org/10.17504/protocols.io.6qpvr89eplmk/v1).

Transperineal Laser Ablation (TPLA) Treatment of Focal Low-Intermediate Risk Prostate Cancer

Background: This interventional pilot study aimed to evaluate the short-term (3 years) efficacy of focal laser ablation (FLA) in treating the index lesion of low-intermediate-risk prostate cancer, along with assessing the safety of the procedure (ClinicalTrials.gov ID NCT04045756). Methods: Forty patients aged between 46 and 86 with histologically proven organ-confined prostate cancer and low-to-intermediate progression risk were included. FLA was performed under percutaneous fusion magnetic resonance/ultrasound guidance in a Day Hospital setting under local anesthesia. Patients underwent regular clinical and functional assessments through the international index of erectile function (IIEF-5) and the International Prostatism Symptom Score (IPSS), PSA measurements, post-procedure MRI scans, and biopsies at 36 months or if positive findings were detected earlier. Statistical analyses were conducted to assess trends in PSA levels and cavity dimensions over time. Results: Forty patients were initially included, with fifteen lost to follow-up. At 36 months, a mean PSA reduction of 60% was observed, and 80% of MRI scans showed no signs of in-field clinically significant residual/recurrent cancer. Biopsies at 36 months revealed no malignant findings in 20 patients. No deterioration in sexual function or urinary symptoms was recorded. Conclusions: FLA appears to be safe, feasible, and effective in the index lesion treatment of low-intermediate-risk prostate cancer, with a high rate of tumor eradication and preservation of quality of life.

Irreversible Electroporation (IRE) for Prostate Cancer (PCa) Treatment: The State of the Art

We evaluated the most recent research from 2000 to 2023 in order to deeply investigate the applications of PCa IRE, first exploring its usage with primary intent and then salvage intent. Finally, we discuss the differences with other focal PCa treatments. In the case of primary-intent IRE, the in-field recurrence is quite low (ranges from 0% to 33%). Urinary continence after the treatment remains high (>86%). Due to several different patients in the studies, the preserved potency varied quite a lot (59-100%). Regarding complications, the highest occurrence rates are for those of Grades I and II (20-77% and 0-29%, respectively). Grade III complications represent less than 7%. Regarding the specific oncological outcomes, both PCa-specific survival and overall survival are 100%. Metastasis-free survival is 99.6%. In a long-term study, the Kaplan-Meier FFS rates reported are 91% at 3 years, 84% at 5 years, and 69% at 8 years. In the single study with salvage-intent IRE, the in-field recurrence was 7%. Urinary continence was still high (93%), but preserved potency was significantly lower than primary-intent IRE patients (23%). In addition, Grade III complications were slightly higher (10.8%). In conclusion, in males with localized low-intermediate-risk prostate cancer, IRE had an excellent safety profile and might have positive results for sexual and urinary function.

An Update on Focal Therapy for Prostate Cancer

Radical treatments and active surveillance are valid therapeutic approaches for low-risk prostate cancer. The oncologic effectiveness and morbidity of Radical Prostatectomy (RP) and radiotherapy have been broadly validated. Focal therapies pursue to reduce the morbidity observed after radical treatments, while preserving the oncologic effectiveness. This study aims to review the state-of-the-art about principles, oncologic effectiveness, morbidity, and side-effects associated with leading focal therapies. We review and summarize articles related with Cryotherapy, High-Intensity Focal Ultrasound (HIFU), Photodynamic Therapy (PDT), and Irreversible Electroporating (IRE) published in MEDLINE from 2000 to 2022. There is a wide heterogeneity in terms of the measurement of effectiveness and morbidity. Hence, comparing different energies, strategies and protocols seem to be unprecise and controversial. Cryosurgery and HIFU have reported more clinical experience than PDT and IRE. Biochemical recurrence rate after the first session varied from 4.5% to 23%, and up to 20% of patients underwent a salvage radical treatment. The reported incidence of erectile disfunction and urinary incontinence ranges from 3% to 50% and 0% to 34%, respectively. None randomized clinical trial comparing any focal therapy to any radical treatment has been published. We conclude that the expansion of focal therapies requires the consolidation of MRI-guided fusion biopsies in everyday clinical practice. Short-term oncologic effectiveness has been proved and supports their usefulness in low-risk patients unfit for surgical treatment. However, long-term effects and the clinical experience in intermediate and high-risk patients remains limited. Currently none of the focal therapies can be considered the Gold Standard for low-risk patients.

MRI-guided Minimally Invasive Focal Therapies for Prostate Cancer

Two cases involving patients diagnosed with localized prostate cancer and treated with MRI-guided focal therapies are presented. Patient selection procedures, techniques, outcomes, challenges, and future directions of MRI-guided focal therapies, as well as their role in the treatment of low- to intermediate-risk localized prostate cancer, are summarized.

One-year Follow-up Results of Transperineal Biopsy For Patients Undergoing Irreversible Electroporation Treatment in Localized Prostate Cancer

OBJECTIVE

This article reports on the early results of a 1-year follow-up study investigating the efficacy of irreversible electroporation in the treatment of localized prostate cancer.

METHODS

The study included 18 out of 40 patients diagnosed with low- and intermediate-risk prostate cancer who underwent irreversible electroporation. Treatment results were evaluated through confirmation biopsies, comparing prostate-specific antigen levels, international prostate symptom scoring, and international index of erectile dysfunction scores before irreversible electroporation and at the 12-month mark.

RESULTS

The mean age of the patients was 61.1 years (SD ±6.5). Out of the 18 patients, 16 were tumor free (88.8%), while 2 experienced recurrences, one within the treatment field and the other outside of it (P < .001). Irreversible electroporation significantly reduced mean prostate-specific antigen levels (6.73 ng/mL vs. 2.05 ng/mL, P < .001), indicating a 69.5% reduction within 12 months. Furthermore, there was a significant improvement in mean international prostate symptom scores at the 12-month followup (10.05 vs. 7.52, P=.003). The mean international index of erectile dysfunction scores before treatment was 19.17 (SD ±5.85), and after irreversible electroporation, it was 18.67 (SD ±6.34), with no statistically significant change (P=.065).

CONCLUSION

The short-term oncological results of irreversible electroporation treatment are promising, particularly for patients in the low- and intermediate-risk groups. Additionally, irreversible electroporation does not negatively impact the international index of erectile dysfunction; however, it may lead to a decrease in international prostate symptom scores.

Transperineal laser ablation (TPLA) with ultrasound/MRI fusion guidance in the treatment of localized radiotherapy-resistant prostate cancer

Objective

The objective of this study was to assess the technical feasibility, safety, and efficacy of transperineal laser ablation (TPLA) guided by ultrasound/magnetic resonance (MR) fusion as a salvage treatment for refractory focal prostate cancer.

Methods

A total of five patients who had undergone radiation therapy (RT) for prostate carcinoma and biochemical recurrence, confirmed by both prostate-specific antigen (PSA) levels and MRI (3T mpMRI), were enrolled in this study. Focal ablation was performed using a 1064 nm diode laser. Post-ablation follow-up was conducted for a duration of 18 months, which included regular PSA sampling, 3T mpMRI, and ultrasound/MR fusion-guided biopsies systematic and targeted at the site of the focal treatment.

Results

The focal ablation procedure was carried out in an outpatient setting regimen with optimal clinical and biochemical outcomes. No recurrence was detected throughout the follow-up period.

Conclusion

TPLA focal treatment effectively manages local recurrences of RT refractory prostate cancer without side-effects or complications. Preservation of quality of life and functional outcomes, along with a >70% reduction in PSA, were achieved.

Advances in knowledge

Our study investigated TPLA as a salvage treatment for low-risk recurrent prostate cancer after RT, demonstrating its tolerability, feasibility, and effectiveness.

Real-Time and Delayed Imaging of Tissue and Effects of Prostate Tissue Ablation

PURPOSE OF REVIEW

Prostate ablation is increasingly being utilized for the management of localized prostate cancer. There are several energy modalities with varying mechanism of actions which are currently used for prostate ablation. Prostate ablations, whether focal or whole gland, are performed under ultrasound and/or MRI guidance for appropriate treatment plan execution and monitoring. A familiarity with different intraoperative imaging findings and expected tissue response to these ablative modalities is paramount. In this review, we discuss the intraoperative, early, and delayed imaging findings in prostate from the effects of prostate ablation.

RECENT FINDINGS

The monitoring of ablation both during and after the therapy became increasingly important due to the precise targeting of the target tissue. Recent findings suggest that real-time imaging techniques such as MRI or ultrasound can provide anatomical and functional information, allowing for precise ablation of the targeted tissue and increasing the effectiveness and precision of prostate cancer treatment. While intraprocedural imaging findings are variable, the follow-up imaging demonstrates similar findings across various energy modalities. MRI and ultrasound are two of the frequently used imaging techniques for intraoperative monitoring and temperature mapping of important surrounding structures. Follow-up imaging can provide valuable information about ablated tissue, including the success of the ablation, presence of residual cancer or recurrence after the ablation. It is critical and helpful to understand the imaging findings during the procedure and at different follow-up time periods to evaluate the procedure and its outcome.

Prediction and Mapping of Intraprostatic Tumor Extent with Artificial Intelligence

Background

Magnetic resonance imaging (MRI) underestimation of prostate cancer extent complicates the definition of focal treatment margins.

Objective

To validate focal treatment margins produced by an artificial intelligence (AI) model.

Design setting and participants

Testing was conducted retrospectively in an independent dataset of 50 consecutive patients who had radical prostatectomy for intermediate-risk cancer. An AI deep learning model incorporated multimodal imaging and biopsy data to produce three-dimensional cancer estimation maps and margins. AI margins were compared with conventional MRI regions of interest (ROIs), 10-mm margins around ROIs, and hemigland margins. The AI model also furnished predictions of negative surgical margin probability, which were assessed for accuracy.

Outcome measurements and statistical analysis

Comparing AI with conventional margins, sensitivity was evaluated using Wilcoxon signed-rank tests and negative margin rates using chi-square tests. Predicted versus observed negative margin probability was assessed using linear regression. Clinically significant prostate cancer (International Society of Urological Pathology grade ≥2) delineated on whole-mount histopathology served as ground truth.

Results and limitations

The mean sensitivity for cancer-bearing voxels was higher for AI margins (97%) than for conventional ROIs (37%, p < 0.001), 10-mm ROI margins (93%, p = 0.24), and hemigland margins (94%, p < 0.001). For index lesions, AI margins were more often negative (90%) than conventional ROIs (0%, p < 0.001), 10-mm ROI margins (82%, p = 0.24), and hemigland margins (66%, p = 0.004). Predicted and observed negative margin probabilities were strongly correlated (R2 = 0.98, median error = 4%). Limitations include a validation dataset derived from a single institution's prostatectomy population.

Conclusions

The AI model was accurate and effective in an independent test set. This approach could improve and standardize treatment margin definition, potentially reducing cancer recurrence rates. Furthermore, an accurate assessment of negative margin probability could facilitate informed decision-making for patients and physicians.

Patient summary

Artificial intelligence was used to predict the extent of tumors in surgically removed prostate specimens. It predicted tumor margins more accurately than conventional methods.

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.

Design and evaluation of an MRI-ready, self-propelled needle for prostate interventions

Prostate cancer diagnosis and focal laser ablation treatment both require the insertion of a needle for biopsy and optical fibre positioning. Needle insertion in soft tissues may cause tissue motion and deformation, which can, in turn, result in tissue damage and needle positioning errors. In this study, we present a prototype system making use of a wasp-inspired (bioinspired) self-propelled needle, which is able to move forward with zero external push force, thereby avoiding large tissue motion and deformation. Additionally, the actuation system solely consists of 3D printed parts and is therefore safe to use inside a magnetic resonance imaging (MRI) system. The needle consists of six parallel 0.25-mm diameter Nitinol rods driven by the actuation system. In the prototype, the self-propelled motion is achieved by advancing one needle segment while retracting the others. The advancing needle segment has to overcome a cutting and friction force while the retracting needle segments experience a friction force in the opposite direction. The needle self-propels through the tissue when the friction force of the five retracting needle segments overcomes the sum of the friction and cutting forces of the advancing needle segment. We tested the performance of the prototype in ex vivo human prostate tissue inside a preclinical MRI system in terms of the slip ratio of the needle with respect to the prostate tissue. The results showed that the needle was visible in MR images and that the needle was able to self-propel through the tissue with a slip ratio in the range of 0.78-0.95. The prototype is a step toward self-propelled needles for MRI-guided transperineal laser ablation as a method to treat prostate cancer.

Laser technology in urologic oncology

Laser technology has been used in Urology since the 80s with a lot of different applications in endoscopic and open surgery. With the developments of the technology and the introduction of new active medium and source of laser energy, this technology have become the gold standard not only in stone surgery but even in benign prostate enlargement (BPE) surgical treatment. Regarding urologic oncology, laser energy has now reached an important role in focal therapy and in conservative treatment. The possibility of having better functional outcomes without any relevant impact on oncological results led to an increased use of laser in penile surgery, with a significant mention in urological guidelines for this option. In urothelial cancers as well, both in conservative management of upper tract tumors that in the treatment of non muscle invasive bladder cancer, a clear role of these relatively new source of energy have been demonstrated. Finally, both in prostate that in renal cancer the strategy of focal therapy may take advantage from this precise and fine technology. In this review we analyzed and described the applications of laser energy in urological cancers with a specific focus on penile, urothelial and prostate cancer.

Alternatives to whole gland treatment for localized prostate cancer: a review of novel focal therapies

PURPOSE OF REVIEW

The mainstays of the management of clinically localized prostate cancer have historically rested upon active surveillance, radiation therapy, or radical prostatectomy. Although both radiation and surgical treatment of localized prostate cancer can achieve excellent oncologic outcomes, the subsequent potential adverse effects of urinary stress incontinence and erectile dysfunction are unappealing to patients. This has led to investigational studies centered upon focal treatment of the cancerous lesion, with the aim to improve quality-of-life outcomes. In this review, we describe numerous novel modalities, including nanoparticle ablation and irreversible electroporation, which are being utilized for the focal treatment of clinically localized prostate cancer.

RECENT FINDINGS

Although many of these novel therapies are in their investigational infancy, several have revealed very promising results both in their post-treatment pathologic outcomes as well as objective quality-of-life measures.

SUMMARY

Initial data regarding novel focal therapy for prostate cancer treatment show promising short-term outcomes in regards to oncologic and quality-of-life assessments. Further investigational studies are needed to determine inclusion criteria for the selection of optimal candidates.

Salvage robot-assisted radical prostatectomy following focal ablation with irreversible electroporation: feasibility, oncological and functional outcomes

Background

To report the feasibility, oncological and functional outcomes of salvage robot-assisted radical prostatectomy (sRARP) for recurrent prostate cancer (PCa) after irreversible electroporation (IRE).

Methods

This was a retrospective analysis of patients who underwent sRARP by a single high-volume surgeon after IRE treatment in our institution. Surgical complications, oncological and functional outcomes were assessed.

Results

15 patients with at least 12 months follow up were identified out of the 234 men who underwent primary IRE between 2013 and 2019. The median [IQR] age was 68 (62–70) years. The median [IQR] time from focal IRE to sRARP was 42 (21–57) months. There were no rectal, bladder or ureteric injuries. The T-stage was pT2 in 9 (60%) patients and pT3a in 6 (40%) patients. Only one (7%) patient had a positive surgical margin. At a median [IQR] follow up of 22 (16–32) months no patient had a biochemical recurrence (PSA > 0.2). All 15 patients were continent (pad-free) by 6 months and 9 (60%) patients had erections sufficient for intercourse with or without PDE5 inhibitors. No predisposing factors were identified for predicting erectile dysfunction after sRARP.

Conclusions

In patients with recurrent or residual significant PCa after focal IRE ablation it is feasible to obtain good functional and oncological outcomes with sRARP. Our results demonstrate that good outcomes can be achieved with sRARP, when respecting close monitoring post-IRE, good patient selection and surgical experience. The limitations of this study are that it is a small series, with short follow up and a lack of standardised quality of life instruments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-00978-w.

The Use of High-Intensity Focused Ultrasound (HIFU) Plus 150mg Bicalutamide as First Line Salvage Therapy for Local Recurrent Prostate Cancer

Patients with localized prostate cancer (PCa) are often treated with radical prostatectomy (RP). However, more than 30% of such patients have high risk of recurrence. Salvage radiotherapy (SRT), androgen deprivation therapy (ADT) and combination of radiotherapy and ADT are the standard care for recurrent PCa. Recently, high intensity focused ultrasound (HIFU) has gradually applied in the treatment of recurrent PCa. Here, we proposed a hypothesis that combined HIFU and bicalutamide 150mg as first line salvage therapy to treat patients with local recurrent PCa with visible lesions due to the following advantages: (1) HIFU is effective in reducing local tumor load, and bicalutamide 150mg is a feasible and safety option to combine with HIFU. (2) Compared with radiotherapy, HIFU plus 150mg bicalutamide is minimal invasiveness with fewer adverse effects and better quality of life(QOL); (3) Radiotherapy can be preserved as the second-line salvage method in the cases who are failure to HIFU and 150mg bicalutamide combination. More clinical trials are warranted to confirm this hypothesis in treatment with recurrent PCa.

Evolution of Focal Therapy in Prostate Cancer: Past, Present, and Future

Organ sparing approaches for the management of localized prostate cancer were developed in part to overcome the morbidity associated with standard, whole gland treatment options. The first description of focal therapy was now over two decades ago and since that time much has changed. The evolution of patient selection, the approach to ablation, and surveillance after focal therapy have mirrored the technologic advancements in the field as well as the improved understanding of the biology of low-grade, low-risk prostate cancer. This review presents the evidence for the basis of focal therapy from the past to the present and future endeavors.

Future perspective of focal therapy for localized prostate cancer

Objective

To summarize the recent literature discussing focal therapy for localized prostate cancer.

Methods

A thorough literature review was performed using PubMed to identify recent studies involving focal therapy for the treatment of localized prostate cancer.

Results

In an effort to decrease the morbidity associated with prostate cancer treatment, many urologists are turning to focal therapy as an alternative treatment option. With this approach, the cancer bearing portion of the prostate is targeted while leaving the benign tissue untouched. Multiparametric magnetic resonance imaging remains the gold standard for visualization during focal therapy, but new imaging modalities such as prostate specific membrane antigen/positron emission tomography and contrast enhanced ultrasound are being investigated. Furthermore, several biomarkers, such as prostate cancer antigen 3 and prostate health index, are used in conjunction with imaging to improve risk stratification prior to focal therapy. Lastly, there are several novel technologies such as nanoparticles and transurethral devices that are under investigation for use in focal therapy.

Conclusion

Focal therapy is proving to be a promising option for the treatment of localized prostate cancer. However, further study is needed to determine the true efficacy of these exciting new technologies.

Photodynamic therapy of prostate cancer using porphyrinic formulations

Prostate cancer (PCa) is the second most frequent cancer diagnosed in men worldwide. Among the common treatment options, photodynamic therapy (PDT) is being considered a promising local therapy to treat this cancer. Although PDT is an established treatment modality approved for several types of cancer, the low solubility, the reduced tumor selectivity, the absorption in the therapeutic window and the poor clearance from the body of the currently approved photosensitizers (PS) hampers its wide clinical application. In this regard, herein we synthesized three fluorinated porphyrinoid derivatives and entrapped them into polyvinylpyrrolidone (PVP) to prevent their aggregation and preserve their desirable photophysical properties under the physiological environment. In vitro studies revealed the negligible dark cytotoxicity of all PVP formulations (PS1@PVP, PS2@PVP and PS3@PVP) at the tested concentrations (5.0 to 20 μM), but also confirmed the significant photodynamic effect of PS2@PVP and PS3@PVP towards the PCa cell line PC-3, upon red light irradiation at an irradiance of 17.6 mW.cm^-2. To provide insight into the underlying mechanisms of cell death under PDT treatment induced by PS2@PVP and PS3@PVP, their intracellular localization in PC-3 cells was firstly investigated by confocal microscopy. Since both PS2@PVP and PS3@PVP nanoparticles were mainly localized in mitochondria, the involvement of this organelle in PDT-induced apoptosis mediated by both formulations was further explored. Western blot analysis revealed that PDT treatment of PC-3 cells with either PS2@PVP or PS3@PVP resulted in the reduction of the expression level of the anti-apoptotic protein Bcl-2. As the photodamage to Bcl-2 after PDT with PS2@PVP and PS3@PVP was accompanied by the further activation of pro-caspase-3, we assumed that upon irradiation the photogenerated reactive oxygen species (ROS) were able to activate a caspase-dependent apoptotic response as a consequence of a post-mitochondrial event. Taken together, these findings demonstrate that among the tested fluorinated porphyrinoids, PS2@PVP and, particularly, PS3@PVP, are significantly more effective in overall PC-3 cell killing than PS1@PVP, thus highlighting their great potential as therapeutic agents for PCa.

Focal therapy for localized cancer: a patent review

INTRODUCTION

Conventional cancer treatments such as radical surgery and systemic therapy targeting the organ or organ system might have side effects because of damage to the surrounding tissue. For this reason, there is a need for new instruments that focally treat cancer.

AREAS COVERED

This review provides a comprehensive overview of the patent literature on minimally and noninvasive focal therapy instruments to treat localized cancer. The medical section of the Google Patents database was scanned, and 128 patents on focal therapy instruments published in the last two decades (2000-2021) were retrieved and classified. The classification is based on the treatment target (cancer cell or network of cancer cells), treatment purpose (destroy the cancerous structure or disable its function), and treatment means (energy, matter, or a combination of both).

EXPERT OPINION

We found patents describing instruments for all groups, except for the instruments that destroy a cancer cell network structure by applying matter (e.g. particles) to the network. The description of the different treatment types may serve as a source of inspiration for new focal therapy instruments to treat localized cancer.

Perceptions of partial gland ablation for prostate cancer among men on active surveillance: A qualitative study

OBJECTIVES –

Partial gland ablation (PGA) therapy is an emerging treatment modality that targets specific areas of biopsy proven prostate cancer (PCa) to minimize treatment-related morbidity by sparing benign prostate. This qualitative study aims to explore and characterize perceptions and attitudes toward PGA in men with very-low-risk, low-risk, and favorable intermediate-risk PCa on active surveillance (AS).

DESIGN –

92 men diagnosed with very-low-risk, low-risk, and favorable intermediate-risk PCa on AS were invited to participate in semi-structured telephone interviews on PGA.

SETTING –

Single tertiary care center located in New York City.

PARTICIPANTS –

20 men with very-low-risk, low-risk, and favorable intermediate-risk PCa on AS participated in the interviews.

MAIN OUTCOME MEASURES –

Emerging themes on perceptions and attitudes toward PGA were developed from transcripts inductively coded and analyzed under standardized methodology.

RESULTS –

Four themes were derived from twenty interviews that represent the primary considerations in treatment decision-making: (1) the feeling of psychological safety associated with low-risk disease; (2) preference for minimally invasive treatments; (3) the central role of the physician; (4) and the pursuit of treatment options that align with disease severity. Eleven men (55%) expressed interest in pursuing PGA only if their cancer were to progress, while 9 men (45%) expressed interest at the current moment.

CONCLUSIONS –

Though an emerging treatment modality, patients were broadly accepting of PGA for PCa with men primarily debating the risks versus benefits of proactively treating low-risk disease. Additional research on men's preferences and attitudes toward PGA will further guide counseling and shared decision-making for PGA.

Does the type of cryoprobe affect oncological and functional outcomes in men with clinically localized prostate cancer treated with primary whole gland prostate cryoablation?

Background

This study aimed to compare the oncological and functional outcomes of primary whole gland cryoablation of the prostate using the variable ice cryoprobe (V-Probe^®) and the conventional fixed-size ice probe.

Materials and methods

We reviewed the Cryo On-Line Data Registry for men who were treated with primary whole gland prostate cryoablation from 2000 through 2017. A multivariate Cox proportional hazards model was used to compare timing to biochemical recurrence between the V-Probe^® and fixed-size ice probe after adjusting for preoperative prostate-specific antigen (PSA), neoadjuvant androgen deprivation therapy, preoperative Gleason score, and preoperative T stage.

Results

A total of 1124 men were included. Median age, Gleason score, and pretreatment PSA were 70 years (interquartile range [IQR]: 65-74 years), 7 (IQR: 6-7) and 5.9 ng/mL (IQR: 4.6-8.1 ng/mL), respectively. The median follow-up time was 25.0 months (IQR: 11.2-48.6 months). V-Probes^® were used in 269 (23.9%) cases and fixed-size ice probes in 858 (76.1%) cases. After adjusting for clinical T stage, PSA, neoadjuvant androgen deprivation therapy and preoperative Gleason score, on the multivariate Cox regression model, we found that there was no significant difference between the type of probe and timing to biochemical recurrence (p = 0.35). On multivariate logistic regression, using the V-Probe^® was associated with a 91% increase in postoperative urinary retention compared to the fixed-size ice probe (p = 0.003).

Conclusions

The use of the V-Probe^® versus conventional fixed-size ice probe was not associated with a difference in biochemical recurrence in patients undergoing primary cryoablation of the prostate.

Investigation of the use of microwave ablation with and without cooling urethral perfusion for thermal ablation of the prostate gland in canine cadavers

OBJECTIVE

To investigate the use of microwave ablation (MWA) with cooling urethral perfusion and with no perfusion (MWA-UP and MWA-NP, respectively) for prostate gland ablation in canine cadavers.

ANIMALS

Cadavers of 18 sexually intact male dogs.

PROCEDURES

After technique refinement in 2 cadavers, laparotomy with ultrasound-guided MWA-UP (n = 8) or MWA-NP (8) of the prostate gland was performed in 16 cadavers. Normograde cystourethroscopy was performed before and after treatment; recorded images were reviewed in a blinded manner for scoring of urethral mucosal discoloration and loss of integrity. Difficulty with cystoscope insertion was recorded if present. Excised prostate glands were fixed for serial sectioning, gross measurements, and calculation of percentage ablation. Percentages of prostate tissue necrosis from MWA, denuded urethral mucosa, and depth of epithelial surface loss in an adjacent section of the colon were estimated histologically. Variables of interest were statistically analyzed.

RESULTS

Difficulty with cystoscope insertion after treatment was significantly more common and scores for urethral mucosal discoloration and loss of integrity were significantly higher (indicating more severe lesions) for the MWA-NP group than for the MWA-UP group. The histologically assessed percentage of denuded urethral mucosa was also greater for the MWA-NP group. Overall median percentage prostate gland ablation was 73%; this result was not associated with prostate gland volume or chronological order of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

MWA-UP induced subtotal thermal necrosis of prostate glands in canine cadavers while limiting urethral mucosal injury. Further study is required to optimize the technique and evaluate its safety and efficacy in vivo as a future curative-intent treatment for prostatic tumors in dogs.

Does prior surgical interventional therapy for BPH affect the oncological or functional outcomes after primary whole-gland prostate cryoablation for localized prostate cancer?

BACKGROUND

To assess whether prior interventional treatment for benign prostatic hyperplasia (BPH) influences oncologic or functional outcomes following primary whole-gland prostate cryoablation.

METHODS

Among 3831 men with prostate cancer who underwent primary whole-gland prostate cryoablation, we identified 160 with a history of prior BPH interventional therapy including transurethral needle ablation (n = 6), transurethral microwave thermotherapy (n = 9), or transurethral resection of the prostate (n = 145). Patients with a history of medically treated or unspecified BPH therapy were excluded from the study. Oncological and functional outcomes were compared between men with and without prior BPH interventional therapy.

RESULTS

In unadjusted analyses, prior interventional BPH therapy was associated with higher risks of postoperative urinary retention (17.5% vs. 9.6%, p = 0.001) and new-onset urinary incontinence (39.9% vs. 19.4%, p > 0.001) compared with no prior therapy. Interventional BPH therapy was not correlated with the risk of developing a rectourethral fistula (p = 0.84) or new-onset erectile dysfunction (ED) at 12 months (p = 0.08) following surgery. On multivariable regression, prior interventional BPH therapy was associated with increased risk of urinary retention (OR 1.9, 95%, p = 0.015) and new-onset urinary incontinence (OR 2.13, p < 0.001). The estimated 5 years Kaplan-Meier survival analysis showed no statistically significant difference (p = 0.3) in biochemical progression free survival between those who underwent interventional BPH therapy compared with those who did not. Local disease recurrence assessed by post cryoablation positive for-cause prostate biopsy showed no significant difference between the two groups (25.4% vs. 28.7%, p = 0.59).

CONCLUSIONS

Prior interventional BPH therapy did not affect the oncologic outcomes nor did it increase the risk of rectourethral fistula or ED in sexually performing patients prior to cryosurgery. Prior interventional BPH therapy was associated with increased risk of urinary retention and incontinence after primary whole-gland prostate cryoablation for prostate cancer.

Ablative options for prostate cancer management

This review provides an overview of the available ablative options for prostate cancer (PCa) management. It contemplates the ablative concepts and the role of prostate ablation in different settings, from primary treatment to repeat ablation, and as an alternative to radiorecurrent disease. Improvements in prostate imaging have allowed us to ablate prostate lesions through thermal, mechanical, and vascular-targeted sources of energy. Partial gland ablation (PGA) has an emerging role in the management of localized PCa because toxicity outcomes have been proven less harmful compared with whole-gland treatments. Although long-term oncological outcomes are yet to be consolidated in comparative studies, recent large series and prospective studies in PGA have reported encouraging results. A second ablation after disease recurrence has demonstrated low toxicity, and future studies must define its potential to avoid radical treatments. PGA is an attractive option for PCa management in different scenarios because of its low-toxicity profile. As expected, recurrence rates are higher than those seen in whole-gland procedures. Long-term oncological outcomes of primary and salvage options are required to endorse it among the standard treatments.

Histotripsy: The Next Generation of High-Intensity Focused Ultrasound for Focal Prostate Cancer Therapy

This article reviews the most current methods and technological aspects of high-intensity focused ultrasound (HIFU), which is termed histotripsy. The rationale for focal therapy for prostate carcinoma rather than prostatectomy, which is being used extensively throughout Europe and Asia, is presented, and an argument for why HIFU is the modality of choice for primary therapy and recurrent disease is offered. The article presents a review of the technical advances including higher ultrasound beam energy than current thermal HIFU which allows for more accurate tissue targeting, less collateral tissue damage, and faster treatment times. Finally, the article presents a discussion about the advantage of ultrasound guidance for histotripsy in preference to magnetic resonance imaging guidance primarily based on cost, ease of application, and portability.

Current state of image-guided focal therapy for prostate cancer

PURPOSE

To review the current evidence regarding protocols and outcomes of image-guided focal therapy (FT) for prostate cancer (PCa).

METHODS

A literature search of the latest published studies assessing primary FT for PCa was carried out in Medline and Cochrane library databases followed by a critical review. FT modalities, follow-up strategies, and oncological and toxicity outcomes were summarized and discussed in this review.

RESULTS

Twenty-four studies with six different sources of energy met the inclusion criteria. A heterogeneity of patient selection, energy sources, treatment templates, and definitions of failure was found among the studies. While a third of patients may be found to have additional cancer burden over 3-5 years following FT, most patients will remain free of a radical procedure. The vast majority of patients maintain urinary continence and good erectile function after FT. Acute urinary retention is the most common complication, whilst severe complications remain rare.

CONCLUSION

An increasing number of prospective studies with longer follow-up have been recently published. Acceptable cancer control and low treatment toxicity after FT have been consistently reported. Follow-up imaging and routine biopsy must be encouraged post-FT. While there is no reliable PSA threshold to predict failure after FT, reporting post-FT positive biopsies and retreatment rates appear to be standard when assessing treatment efficacy.

Prostate cancer "super-active surveillance" era opened by vascular targeted photodynamic therapy

The "super-active surveillance" concept denotes any active surveillance optimization that allows longer surveillance periods, with the main intention of avoiding overtreatment, by safely eliminating or postponing radical treatment. Super-active surveillance might add to the oncological control with minimal functional impact and similar quality of life compared to active surveillance, which has proved to be safe in well-selected patients. Vascular targeted photodynamic therapy has pioneering shown to significantly reduce the upgrade on subsequent biopsies, resulting in fewer cases converted to radical therapy, and any energy source can be applied to the super-active surveillance concept allowing more men to consider a tissue-preserving therapy for prostate cancer.