Safety and Feasibility of Soractelite Transperineal Focal Laser Ablation for Prostate Cancer and Short-term Quality of Life Analysis from a Multicenter Pilot Study

Laser-focused ablative therapy for prostate cancer and benign prostatic hyperplasia: A review of current applications and future directions

Focal Laser ablation (FLA), or interstitial Laser thermotherapy, is a promising minimally invasive approach for the treatment of localized prostate cancer and benign prostatic hyperplasia. This technique is gaining popularity among patients due to its ability to preserve pre-treatment quality of life. The examination is performed under magnetic resonance imaging (in bore) or ultrasound guidance, via a percutaneous transrectal or transperineal route. Under transperineal ultrasound guidance, FLA can use up to four Laser fibers to create confluent zones of tissue ablation, enabling treatment of larger prostate- or tumor volumes. Primary indications for FLA include intermediate-risk localized prostate cancer and benign prostatic hyperplasia refractory to medical treatment due to ineffectiveness or side effects. The intervention is typically performed under light sedation or under locoregional anesthesia. FLA lasts approximately 10 min, with a total intervention time of < 60 min on an outpatient basis. Patients are often discharged with either a suprapubic or bladder catheter to prevent urinary retention, especially if the ablated area is close to the urethra. Minor complications are rare and limited to transient voiding dysfunction, urinary tract infection, or hematuria. Major complications, such as rectoprostatic fistula, are avoided by rectoprostatic hydrodissection. FLA is an effective, well-tolerated option in the minimally invasive treatment of prostate disease, offering rapid treatment times, low complication rates, and preservation of quality of life for appropriately selected patients. However, variability in recurrence rates following FLA for prostate cancer highlights the need for further investigation into optimal patient selection for this treatment.

New kids on the block: MRI guided transrectal focused US, TULSA, focal laser ablation, histotripsy - a comprehensive review

INTRODUCTION

Prostate cancer (PCa) management poses challenges due to treatment-related morbidities associated with conventional therapies. Focal therapy (FT) is emerging as a promising alternative for intermediate-risk PCa, aiming to selectively target localized cancerous lesions while preserving healthy tissue. This review explores emerging FT modalities for PCa treatment, focusing on transrectal MRI-guided focused ultrasound surgery (MRgFUS), transurethral ultrasound ablation (TULSA), focal laser ablation (FLA), and histotripsy.

METHODS

A comprehensive literature search was conducted to identify studies and clinical trials related to FT. Relevant articles were selected and data were synthesized to provide insights into the efficacy and feasibility of MRgFUS, TULSA, FLA, and histotripsy for FT.

RESULTS

MRgFUS utilizes transrectal high-intensity focused ultrasound under MRI guidance to selectively ablate cancerous tissue, demonstrating positive outcomes in oncologic control and preservation of urinary and sexual function. TULSA employs transurethral delivery of high-intensity ultrasound energy under MRI guidance, showing promising results for whole gland treatment. FLA benefits from precise ablation, indicating effectiveness in tumor destruction while preserving quality-of-life. Histotripsy, a mechanical ablation method, exhibits promise by inducing tissue fractionation through bubble activity, offering advantages such as tissue selectivity and real-time treatment monitoring.

CONCLUSION

Emerging FT modalities present promising alternatives for the management of localized PCa, offering personalized treatment. Further research and clinical trials are warranted to establish the long-term efficacy of these techniques in PCa management.

Transperineal MR Fusion Laser Ablation of Prostate Cancer in Office Setting: 1 Year Efficacy and Safety Outcomes in Intermediate-Risk Patients

Introduction: Focal therapy (FT) is an emerging option for intermediate-risk prostate cancer (IR-PCa). Transperineal MRI fusion laser ablation of PCa (TPFLA) is a novel FT technique with limited data reported. We conducted a phase I clinical trial evaluating the safety, feasibility, and 1-year oncologic results for patients with IR-PCa treated with TPFLA in an office setting. Materials and Methods: NCT05241236 aimed to evaluate TPFLA for the International Society of Urological Pathology-grade 2 (ISUP-2) tumors. All procedures were performed in the office using MR/US fusion imaging. The diode interstitial laser system fibers were applied through the perineum using local anesthesia. The primary outcome was safety and tolerability. Pain scores were recorded using analog scales. Thirty-day adverse events and 1-year prostate biopsy oncologic outcomes were noted. Functional outcomes at 3 months and 1 year were compared with baseline as well. Results: Thirty patients accrued had TPFLA safely in the office with no complications. TPFLA median pain score was 1. At 30 days, one man required a transurethral resection of the prostate (TURP). There were no imaging demonstrable cancers at 3 months and a significant improvement in urinary function (p = 0.001) was noted and sustained for the year. No patient experienced urinary incontinence. No changes in sexual function were observed (p = 0.7). At 1 year, 25/30 (83%) had no clinically significant cancer. However, 14 had PCa, in 5 (17%) solely in treated areas, all ISUP-1. Seven had PCa outside the treated areas. Two had infield and outfield recurrences, both were ISUP 2. At study closure, 16 patients were free from PCa, 3 were on active surveillance, 9 were treated focally with cryoablation, and 2 were converted to radical surgical procedure. Conclusions: TPFLA appears to be a safe and an effective focal therapy for IR-PCa, offering a potential alternative to more radical treatments with a minimal periprocedural impact. Longer follow-up and larger studies are needed to confirm these results.

Anatomic and Clinical Effects of Focal Laser Ablation of the Prostate on Symptomatic Benign Prostatic Hyperplasia

BACKGROUND/OBJECTIVES

Laser ablation is a promising technique for tissue-debulking in patients with symptomatic benign prostatic hyperplasia (BPH). This study evaluated the effects of focused laser ablation of the prostate (FLA) on urinary symptoms for patients with BPH.

METHODS

Since 2018, 62 patients had bilateral prostate FLA for prostate cancer and/or symptomatic BPH, defined as an international prostate symptom score (IPSS) ≥11, and have 6-month follow-up data. Urinary and sexual health were scored with standardized surveys while imaging defined prostate anatomy. FLA was performed as an outpatient procedure with either transrectal MRI-guided (n = 24) or transperineal ultrasound-guided (n = 38) laser fiber placement to debulk the prostate and/or ablate cancer foci plus margins. Enhanced prostate MRI was performed immediately or up to 2 days later to assess the treatment zones. Follow-up then consisted of PSA levels every 6 months and MRI at 6-12 months and then yearly combined with patient sexual/urinary surveys and clinical assessments.

RESULTS

All patients had technically successful FLA and 6-month clinical and imaging follow-up. At 6-month follow-up, mean IPSS was reduced by 43% relative to baseline (10.4 vs. 18.4), mean prostate volume was reduced by 30% (42.2 vs. 60.5 mL), and mean PSA was reduced by 58% (4.3 vs. 10.2 ng/mL). All of these changes were statistically significant (p ≤ 0.008). Compared with baseline, there was no significant change in the SHIM score at 6 months (16.0 vs. 16.8; p = 0.59). In a subset of patients for whom 12-month data were available, there were significant reductions in PSA (61%; 4.1 vs. 10.5 ng/mL; p < 0.002) and IPSS (45%; 9.9 vs. 17.9; p < 0.002), while the 12-month SHIM score was not significantly different from baseline (15.2 vs. 16.0; p = 0.27). Mean laser irradiation time was 19 min with a mean energy deposition of 13,562 J. The most frequent adverse events were prolonged urinary catheterization in 10 patients (16%) and urinary tract infection in 8 (13%).

CONCLUSIONS

FLA is a safe and effective tissue-debulking technique for patients with symptomatic BPH. This outpatient procedure requires minimal procedure time and can be performed without the need for operating rooms or cystoscopy. Our results are consistent with those of previous studies indicating that FLA preserves sexual function.

Focal Therapy for Prostate Cancer: Recent Advances and Insights

Focal therapy has emerged as a balanced middle ground aiming to reduce overtreatment and the risk of progression, as well as patients' distress and anxiety. Focal therapy and partial gland ablation prioritize the precise elimination of the index lesion and a surrounding safety margin to optimize treatment outcomes and lower the risk of residual disease. The paradigm of whole-gland ablation has shifted towards more targeted approaches. Several treatment templates ranging from subtotal and hemiablation to "hockey-stick", quadrant, and even focal lesion ablation have emerged. Many types of energy may be utilized during focal treatment. First, focal therapy can be grossly classified into thermal vs. non-thermal energy. The aim of this non-systematic review is to offer a comprehensive analysis of recently available evidence on focal therapy for PCa.

MRI-directed Micro-US-guided Transperineal Focal Laser Ablation for Localized Prostate Cancer: A 1-year Follow-up Study

Background MRI-guided focal laser ablation (FLA) is a promising treatment in localized prostate cancer (PCa). MRI-guided micro-US FLA shows potential for outpatient use, but its clinical application remains unexplored. Purpose To evaluate the safety, feasibility, and 12-month functional and oncologic outcomes of MRI-guided micro-US transperineal FLA in localized PCa and to assess the accuracy of micro-US in showing lesions depicted at MRI with Prostate Imaging Reporting and Data System (PI-RADS) score of 3 or higher. Materials and Methods This prospective, single-center observational study (July 2020 to June 2023) included participants with localized low- or intermediate-risk PCa and PI-RADS 3 or higher lesions (≤20 mm). Single- or multifiber FLA was performed at 1064 nm, guided by MRI-delineated image fusion. At 12 months, recurrence rates, complications, erectile function scores, and urinary symptom scores were assessed. Mann-Whitney U and Wilcoxon tests were used for comparisons. Results Fifty-five male participants (median age, 70 years; IQR, 62-74 years) with 58 lesions that were PI-RADS 3 or higher underwent transperineal FLA, with a 12-month follow-up for 33 participants. The median prostate-specific antigen level was 7.0 ng/mL (IQR, 5.6-9.0 ng/mL), 43 of 58 lesions (74%) had a Gleason score of 3 + 4, and 10 of 58 lesions (17%) had a Gleason score of 3 + 3. Single-fiber and multifiber FLA were used to treat 21 of 58 (36%) and 37 of 58 (64%) tumors, respectively. At micro-US, 53 of 58 (91%) tumors were successfully visualized. Multifiber FLA produced larger ablation volumes than did single-fiber treatment (median, 15 mL [IQR, 8-22 mL] vs 4.5 mL [IQR, 2.8-9.2 mL]; P < .001). At 12 months, biopsies in 35 treated tumors showed 17 recurrences (49%), including 13 in-field and four out-of-field recurrences. In-field recurrences occurred in 10 of 18 (56%) single-fiber and three of 17 (18%) multifiber cases. At 12 months, erectile function scores decreased compared with baseline (median International Index of Erectile Function score, 19 [IQR, 12-24] vs 21 [IQR, 15-24]; P < .001), whereas urinary function remained stable (median International Prostatic Symptom Score, 2 [IQR, 2-9] vs 6 [IQR, 3-11]; P = .72). One rectoprostatic fistula developed and required surgery. Conclusion Multifiber micro-US-guided FLA was safe and feasible, with 18% recurrence at 1-year follow-up. Clinical trial registration no. NCT05163197 © RSNA, 2024 Supplemental material is available for this article.

Outcomes of CEM43 in Predicting Thermal Damage Induced by Focal Laser Ablation in Controlled Ex Vivo Experiments: A Comparison to Histology and MRI

BACKGROUND

Focal laser ablation (FLA) serves as a targeted therapy for prostate cancer (PCa). Clinical studies have demonstrated significant variations in ablation volumes with consistent fiber configurations. Consequently, a prediction model is needed for the safe application of FLA in treating PCa.

OBJECTIVE

This study aimed to evaluate the reproducibility of FLA-induced temperature profiles in controlled ex vivo experiments using clinical laser treatment protocols. Additionally, it sought to examine the effectiveness of the CEM43 model in predicting the zone of irreversible damage (ZID) and to compare these findings with outcomes derived from the Arrhenius model.

METHODS

Freshly excised postmortem human prostate and porcine liver specimens were used for controlled ex vivo ablation. Tissues were secured in a Perspex sample holder for precise placement of the laser fiber and thermocouples. FLA was conducted with a 1064-nm Nd:YAG laser at 3 W in continuous-wave mode for 10 min. Pre- and post-FLA 3D T1-weighted 7 T MRI scans were obtained to assess the treatment area. Whole-mount hematoxylin and eosin histological slides were prepared and digitized. On histology, the ZID was defined as the total of vaporized, carbonized, and coagulated tissue. A 2D thermal development map was created from temperature data, using bi-cubic interpolation. The cumulative equivalent thermal isoeffect dose at 43°C in minutes (CEM43) model was applied to predict the ZID, with 240 equivalent minutes (240-CEM43) used as the damage threshold. Additionally, the Arrhenius thermal model was used for comparison of CEM43 results. Predicted ZIDs were compared to MRI and histology.

RESULTS

FLA treatment was performed on ex vivo human prostate samples (n = 2) and porcine liver specimens (n = 5). For human prostate tissue, FLA did not result in an identifiable ZID upon histological macroscopic examination or a lesion on MRI. Ex vivo porcine liver samples showed a clearly demarcated oval-shaped hyperintense lesion surrounding the laser fiber tip on post-FLA MRI. The MRI lesion (range 1.6-2.1 cm2) corresponded with the shape and location of the ZID on histology, but was smaller (median 1.7 vs. 3.2, p = 0.02). Histological examination of porcine liver samples revealed ZIDs ranging from 2.1 to 4.1 cm2, whereas 240-CEM43-predicted ZIDs ranged from 3.3 to 3.8 cm2. Although the median 240-CEM43-predicted ZID was not significantly larger than the histology ZID (3.8 vs. 3.2 cm2, p = 0.22), it tended to overpredict the histological results in most experiments. The median Arrhenius-predicted ZID was similar to the histological ZID (3.2 vs. 3.2 cm2, p = 0.56), but varied in size when comparing individual experiments (range 2.5-3.2 cm2).

CONCLUSION

FLA on ex vivo human prostate showed no thermal damage on histopathology or MRI. Ex vivo porcine liver FLA resulted in identifiable ZID on histology and lesions on MRI. 240-CEM43 generally overestimated the ZID and had less variability compared to histology. Results from the Arrhenius model were in better agreement with the histology findings, but still did not predict the individual FLA-induced histological thermal damage. Inter-experiment ZID variability underlines the need for developing a more comprehensive predictive dosimetry model for FLA in PCa treatment.

Transperineal Laser Ablation for Focal Therapy of Localized Prostate Cancer: 12-Month Follow-up Outcomes from a Single Prospective Cohort Study

INTRODUCTION AND OBJECTIVES

To evaluate the oncological and functional outcomes of transperineal laser ablation (TPLA) as the focal therapy for localized prostate cancer (PCa) after a 12-month follow-up.

MATERIALS AND METHODS

Patients with low- and intermediate-risk localized PCa were prospectively treated with focal TPLA between July 2021 and December 2022. The inclusion criteria were the following: clinical stage < T2b; PSA < 20 ng/mL; International Society of Urological Pathology (ISUP) grade ≤ 2; MRI-fusion biopsy-confirmed lesion classified as PI-RADS v2.1 ≥ 3. Intra-, peri-, and post-operative data were collected. Variables including age, PSA, prostate volume (PVol), Charlson's Comorbidity Index (CCI), International Prostate Symptom Score (IPSS) with QoL score, International Index of Erectile Function (IIEF-5), International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), and Male Sexual Health Questionnaire-Ejaculatory Dysfunction Short Form (MSHQ-EjD) were collected at baseline and at 3, 6 and 12 months after TPLA. Post-operative mpMRI was performed at 3 and 12 months. Finally, all patients underwent prostatic re-biopsy under fusion guidance at 12 months. The success of this technique was defined as no recurrence in the target treated lesion at the 12-month follow up.

RESULTS

Twenty-four patients underwent focal TPLA. Baseline features were age [median 67 years (IQR 12)], PSA [5.7 ng/mL (3.9)], PVol [49 mL (27)], CCI [0 (0)], IPSS [11 (9)], IPSS-QoL [2 (2)], IIEF-5 [21 (6)], ICIQ-SF [0 (7)], MSHQ-EjD ejaculation domain [14 (4)] and bother score [0 (2)]. Median operative time was 34 min (IQR 12). Median visual analogue scale (VAS) 6 h after TPLA was 0 (IQR 1). The post-operative course was regular for all patients, who were discharged on the second post-operative day and underwent catheter removal on the seventh post-operative day. No patient had incontinence at catheter removal. A significant reduction in PSA (p = 0.01) and an improvement in IPSS (p = 0.009), IPSS-QoL (p = 0.02) and ICIQ-SF scores (p = 0.04) compared to baseline were observed at the 3-month follow-up. Erectile and ejaculatory functions did not show any significant variation during the follow-up. No intra- and peri-operative complications were recorded. Three Clavien-Dindo post-operative complications were recorded (12%): grade 1 (two cases of urinary retention) and grade 2 (one case of urinary tract infection). At the 12-month follow-up, eight patients showed mpMRI images referable to suspicious recurrent disease (PIRADS v2.1 ≥ 3). After re-biopsy, 7/24 patients' (29%) results were histologically confirmed as PCa, 3 of which were recurrences in the treated lesion (12.5%). The success rate was 87.5%.

CONCLUSIONS

The focal TPLA oncological and functional results seemed to be encouraging. TPLA is a safe, painless, and effective technique with a good preservation of continence and sexual outcomes. Recurrence rate at 12 months was about 12.5%.

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.

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.

Transperineal laser ablation of the prostate as a treatment for benign prostatic hyperplasia and prostate cancer: The results of a Delphi consensus project

Objective

To evaluate transperineal laser ablation (TPLA) with Echolaser® (Echolaser® TPLA, Elesta S.p.A., Calenzano, Italy) as a treatment for benign prostatic hyperplasia (BPH) and prostate cancer (PCa) using the Delphi consensus method.

Methods

Italian and international experts on BPH and PCa participated in a collaborative consensus project. During two rounds, they expressed their opinions on Echolaser® TPLA for the treatment of BPH and PCa answering online questionnaires on indications, methodology, and potential complications of this technology. Level of agreement or disagreement to reach consensus was set at 75%. If the consensus was not achieved, questions were modified after each round. A final round was performed during an online meeting, in which results were discussed and finalized.

Results

Thirty-two out of forty invited experts participated and consensus was reached on all topics. Agreement was achieved on recommending Echolaser® TPLA as a treatment of BPH in patients with ample range of prostate volume, from <40 mL (80%) to >80 mL (80%), comorbidities (100%), antiplatelet or anticoagulant treatment (96%), indwelling catheter (77%), and strong will of preserving ejaculatory function (100%). Majority of respondents agreed that Echolaser® TPLA is a potential option for the treatment of localized PCa (78%) and recommended it for low-risk PCa (90%). During the final round, experts concluded that it can be used for intermediate-risk PCa and it should be proposed as an effective alternative to radical prostatectomy for patients with strong will of avoiding urinary incontinence and sexual dysfunction. Almost all participants agreed that the transperineal approach of this organ-sparing technique is safer than transrectal and transurethral approaches typical of other techniques (97% of agreement among experts). Pre-procedural assessment, technical aspects, post-procedural catheterization, pharmacological therapy, and expected outcomes were discussed, leading to statements and recommendations.

Conclusion

Echolaser® TPLA is a safe and effective procedure that treats BPH and localized PCa with satisfactory functional and sexual outcomes.

Minimally invasive techniques in quest of Holy Grail of surgical management of enlarged prostates: a narrative review

PURPOSE

Past decade has seen a renewed interest in minimally invasive surgical techniques (MISTs) for management of enlarged prostate. This narrative review aims to explore newer MIST for benign prostatic hyperplasia (BPH) which are not yet integrated into established societal guidelines.

METHODS

We conducted a literature search across PubMed, Google Scholar, and FDA ClinicalTrials.gov databases on June 1st, 2023, to identify studies published within the past decade exploring various MISTs for BPH. Additionally, we gathered insights from abstracts presented in meetings of professional associations and corporate websites. We broadly classified these procedures into three distinct categories: energy-based, balloon dilation, and implant/stent treatments. We collected detail information about the device, procedure details, its inclusion and exclusion criteria, and outcome.

RESULTS

Our review reveals that newer energy-based MISTs include Transperineal Laser Ablation, Transurethral Ultrasound Ablation, and High-Intensity Focused Ultrasound. In the sphere of balloon dilation, Transurethral Columnar Balloon Dilation and the Optilume BPH Catheter System were gaining momentum. The noteworthy implants/stents that are on horizon include Butterfly Prostatic Retraction Device, Urocross Expander System, Zenflow Spring System, and ProVee Urethral Expander System.

CONCLUSION

The exploration of various MISTs reflects ongoing efforts to enhance patient care and address limitations of existing treatments. This review provides a bird-eye view and valuable insights for urologists and researchers seeking to navigate the dynamic landscape of MISTs in the quest for effective and minimally invasive solutions for enlarged prostates.

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.

Reliable Visualization of the Treatment Effect of Transperineal Focal Laser Ablation in Prostate Cancer Patients by Magnetic Resonance Imaging and Contrast-enhanced Ultrasound Imaging

Background

Transperineal focal laser ablation (TPLA) treatment for prostate cancer (PCa) is an experimental focal ablative therapy modality with low morbidity. However, a dosimetry model for TPLA is lacking.

Objective

To determine (1) the three-dimensional (3D) histologically defined ablation zone of single- and multifiber TPLA treatment for PCa correlated with magnetic resonance imaging (MRI) and contrast-enhanced ultrasound (CEUS) and (2) a reliable imaging modality of ablation zone volumetry.

Design setting and participants

This was a prospective, multicenter, and interventional phase I/II pilot study with an ablate-and-resect design. TPLA was performed in 12 patients with localized prostate cancer divided over four treatment regimens to evaluate potential variation in outcomes.

Intervention

TPLA was performed approximately 4 wk prior to robot-assisted radical prostatectomy (RARP) in a daycare setting using local anesthesia.

Outcome measurements and statistical analysis

Four weeks after TPLA, ablation zone volumetry was determined on prostate MRI and CEUS by delineation and segmentation into 3D models and correlated with whole-mount RARP histology using the Pearson correlation index.

Results and limitations

Twelve office-based TPLA procedures were performed successfully under continuous transrectal ultrasound guidance using local perineal anesthesia. No serious adverse events occurred. A qualitative analysis showed a clear demarcation of the ablation zone on T2-weighted MRI, dynamic contrast-enhanced MRI, and CEUS. On pathological evaluation, no remnant cancer was observed within the ablation zone. Ablation zone volumetry on CEUS and T2-weighted MRI compared with histology had a Pearson correlation index of r = 0.94 (95% confidence interval [CI] 0.74-0.99, p < 0.001) and r = 0.93 (95% CI 0.73-0.98, p < 0.001), respectively.

Conclusions

CEUS and prostate MRI could reliably visualize TPLA ablative effects after minimally invasive PCa treatment with a high concordance with histopathological findings and showed no remnant cancer.

Patient summary

The treatment effects of a novel minimally invasive ablation therapy device can reliably be visualized with radiological examinations. These results will improve planning and performance of future procedures.