Surveillance after prostate focal therapy

Evaluation of functional and oncological outcomes of localized prostate cancer after different minimally invasive therapeutic methods: A single center experience

OBJECTIVES

To study the functional and oncological results of minimally invasive treatment methods: cryoablation, brachytherapy, and high-intensity focused ultrasound (HIFU) therapy of localized prostate cancer in a single hospital.

METHODS

One hundred sixty patients with localized prostate cancer were treated with minimally invasive methods (53, 52, 55 patients with cryoablation, brachytherapy and HIFU therapy, respectively). Prostate-specific antigen and evaluation of post-procedure biopsies were used as an assessment. The review of functional indicators and quality of life was made with International Index of Erectile Function (IIEF-5), International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), quality of life (QoL) questionnaires.

RESULTS

Patients after cryoablation showed worse results of oncological control according to positive repeat biopsies, best indicators were observed after brachytherapy. When considering the IPSS results, there were statistically significantly worse scores in the brachytherapy group in the early postoperative period, these differences do not reach statistical significance in the late period in the brachytherapy and cryoablation groups. Patients in the cryoablation group showed worse indicators of IIEF-5; in the early postoperative period; in the late follow-up period, the indicators of erectile function in patients in the cryoablation group did not statistically significantly differ from those in patients after brachytherapy. Patients after HIFU therapy showed fewer cases of de novo erectile dysfunction during the follow-up period of 3 years, higher average IIEF-5 scores, lower IPSS scores and better QoL results.

CONCLUSION

The recurrence of prostate cancer was statistically significantly higher in the International Society of Urological Pathology (ISUP) 3 grade group. HIFU therapy had better urination indicators compared to other groups, that can be associated with the laser enucleation of prostatic hyperplasia. The advantage was noted in patients after HIFU therapy when comparing the parameters to the IIEF-5 thus, HIFU treatment had a better impact on patients' QoL with localized prostate cancer.

The Transatlantic Recommendations for Prostate Gland Evaluation with Magnetic Resonance Imaging After Focal Therapy (TARGET): A Systematic Review and International Consensus Recommendations

BACKGROUND AND OBJECTIVE

Magnetic resonance imaging (MRI) can detect recurrences after focal therapy for prostate cancer but there is no robust guidance regarding its use. Our objective was to produce consensus recommendations on MRI acquisition, interpretation, and reporting after focal therapy.

METHODS

A systematic review was performed in July 2022 to develop consensus statements. A two-round consensus exercise was then performed, with a consensus meeting in January 2023, during which 329 statements were scored by 23 panellists from Europe and North America spanning urology, radiology, and pathology with experience across eight focal therapy modalities. Using RAND Corporation/University of California-Los Angeles methodology, the Transatlantic Recommendations for Prostate Gland Evaluation with MRI after Focal Therapy (TARGET) were based on consensus for statements scored with agreement or disagreement.

KEY FINDINGS AND LIMITATIONS

In total, 73 studies were included in the review. All 20 studies (100%) reporting suspicious imaging features cited focal contrast enhancement as suspicious for cancer recurrence. Of 31 studies reporting MRI assessment criteria, the Prostate Imaging-Reporting and Data System (PI-RADS) score was the scheme used most often (20 studies; 65%), followed by a 5-point Likert score (six studies; 19%). For the consensus exercise, consensus for statements scored with agreement or disagreement increased from 227 of 295 statements (76.9%) in round one to 270 of 329 statements (82.1%) in round two. Key recommendations include performing routine MRI at 12 mo using a multiparametric protocol compliant with PI-RADS version 2.1 standards. PI-RADS category scores for assessing recurrence within the ablation zone should be avoided. An alternative 5-point scoring system is presented that includes a major dynamic contrast enhancement (DCE) sequence and joint minor diffusion-weighted imaging and T2-weighted sequences. For the DCE sequence, focal nodular strong early enhancement was the most suspicious imaging finding. A structured minimum reporting data set and minimum reporting standards for studies detailing MRI data after focal therapy are presented.

CONCLUSIONS AND CLINICAL IMPLICATIONS

The TARGET consensus recommendations may improve MRI acquisition, interpretation, and reporting after focal therapy for prostate cancer and provide minimum standards for study reporting.

PATIENT SUMMARY

Magnetic resonance imaging (MRI) scans can detect recurrent of prostate cancer after focal treatments, but there is a lack of guidance on MRI use for this purpose. We report new expert recommendations that may improve practice.

Evaluating Diagnostic Accuracy and Inter-reader Agreement of the Prostate Imaging After Focal Ablation Scoring System

Background and objective

Focal therapy (FT) is increasingly recognized as a promising approach for managing localized prostate cancer (PCa), notably reducing treatment-related morbidities. However, post-treatment anatomical changes present significant challenges for surveillance using current imaging techniques. This study aimed to evaluate the inter-reader agreement and efficacy of the Prostate Imaging after Focal Ablation (PI-FAB) scoring system in detecting clinically significant prostate cancer (csPCa) on post-FT multiparametric magnetic resonance imaging (mpMRI).

Methods

A retrospective cohort study was conducted involving patients who underwent primary FT for localized csPCa between 2013 and 2023, followed by post-FT mpMRI and a prostate biopsy. Two expert genitourinary radiologists retrospectively evaluated post-FT mpMRI using PI-FAB. The key measures included inter-reader agreement of PI-FAB scores, assessed by quadratic weighted Cohen's kappa (κ), and the system's efficacy in predicting in-field recurrence of csPCa, with a PI-FAB score cutoff of 3. Additional diagnostic metrics including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were also evaluated.

Key findings and limitations

Scans from 38 patients were analyzed, revealing a moderate level of agreement in PI-FAB scoring (κ = 0.56). Both radiologists achieved sensitivity of 93% in detecting csPCa, although specificity, PPVs, NPVs, and accuracy varied.

Conclusions and clinical implications

The PI-FAB scoring system exhibited high sensitivity with moderate inter-reader agreement in detecting in-field recurrence of csPCa. Despite promising results, its low specificity and PPV necessitate further refinement. These findings underscore the need for larger studies to validate the clinical utility of PI-FAB, potentially aiding in standardizing post-treatment surveillance.

Patient summary

Focal therapy has emerged as a promising approach for managing localized prostate cancer, but limitations in current imaging techniques present significant challenges for post-treatment surveillance. The Prostate Imaging after Focal Ablation (PI-FAB) scoring system showed high sensitivity for detecting in-field recurrence of clinically significant prostate cancer. However, its low specificity and positive predictive value necessitate further refinement. Larger, more comprehensive studies are needed to fully validate its clinical utility.

Combination of DNA methylation biomarkers with multiparametric magnetic resonance and ultrasound imaging fusion biopsy to detect the local spread of prostate cancer

BACKGROUND

This study aimed to investigate the extent of field cancerization adjacent to index lesions in prostate cancer (PCa) by measuring DNA methylation of selected tumor suppressor genes in the perifocal tissue of PCa not visible on multiparametric magnetic resonanse imaging (mpMRI) for the safe zone of focal therapy identification.

METHODS

A total of 272 patients were enrolled in this study, 44 patients' tissue biosamples were included in the field cancerization research, and 272 urine samples were included in the urine-based test development. Targeted biopsies were performed using the mpMRI/ultrasoundimage fusion system.

RESULTS

Quantitative analysis revealed significantly higher DNA methylation levels of RARB, RASSF1, GSTP1 & APC genes in the index lesion compared with perifocal tissue samples 10 mm away from it (p < 0.0001). Notably, the RARB, GSTP1 & APC and RARB, RASSF1, GSTP1 & APC biomarker combinations exhibited the highest sensitivity and specificity comparing the extent of DNA methylation in index lesions and noncancerous prostate tissues 20 mm away (both area under the curve [AUC] = 0.98; p < 0.0001). The analysis of the potential urinary biomarkers showed that the combination of all four DNA methylation biomarkers with prostate-specific antigen (PSA) or PSA density (PSAD) in the blood significantly improves the detection of clinically significant PCa (csPCa). The combination of the four-biomarker test with PSAD allowed the identification of csPCa with ≥90% sensitivity and specificity.

CONCLUSION

Thus, this study suggests that for focal therapy by region target hemi-ablation, the safe distance from the index lesion is no less than 10 mm. Noninvasive urine DNA methylation tests in combination with PSAD could be used for further follow-up of the patients, but larger prospective studies with external validation are needed.

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.

Surveillance one year post focal cryotherapy for clinically significant prostate cancer using mpMRI and PIRADS v2.1: An initial experience from a prospective phase II mandatory biopsy study

Objectives

Multiparametric magnetic resonance imaging (mpMRI) surveillance post focal cryotherapy (FT) of prostate cancer is challenging as post treatment artefacts alter mpMRI findings. In this initial experience, we assessed diagnostic performance of mpMRI in detecting clinically significant prostate cancer (csPCa) after FT.

Materials and methods

This single-centre phase II prospective clinical trial recruited 28 men with localized csPCa for FT between October 2019 and April 2021. 12-months post FT mpMRI were performed prior to biopsy and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of all mpMRI positive subjects were analysed. Chi square goodness of fit test correlated biopsy positive PIRADS3 (P3) and PIRADS4/5 lesions with histology grade group. One way ANOVA test assessed performance of ADC values in differentiating csPCa, non csPCa and benign lesions.

Results

Sensitivity, specificity, PPV and NPV of mpMRI were 100%, 14.28%, 53.84% and 100% for subjects with histologically proven cancer. Correlation of PIRADS v2.1 scores with histologically proven prostate cancer was statistically significant (p < 0.5). Correlation of P3 lesions with non-csPCa was statistically significant (p < 0.02535). Higher ADC value was associated with benign histology (adjusted odds ratio OR 0.97, 95% confidence interval: 0.94, 0.99) (p = 0.008). Among the malignant lesions, higher ADC value was associated with non-csPCa (adjusted OR: 0.97; 95% CI: 0.95, 0.99) (p = 0.032).

Conclusion

mpMRI is highly sensitive in detecting residual cancer. ADC values and PIRADS scores may be of value in differentiating csPCa from non-csPCa with a potential for risk stratification of men requiring re-biopsy versus non-invasive surveillance of remnant prostate.

Image-Guided Prostate Cryoablation: State-of-the-Art

Image-guided focal therapy has increased in popularity as a treatment option for patients with primary and locally recurrent prostate cancer. This review will cover the basic indications, evaluation, treatment algorithm, and follow-up for patients undergoing image-guided ablation of the prostate. Additionally, this paper will serve as an overview of some technical approaches to cases so that physicians can familiarize themselves with working in this space. While the focus of this paper is prostate cryoablation, readers will obtain a basic literature overview of some of the additional available image-guided treatment modalities for focal prostate therapy.

Treatment of localized prostate cancer in elderly patients: the role of partial cryoablation

PURPOSE

To evaluate oncological outcomes of partial gland cryoablation (PGC) for localized prostate cancer (PCa) in a cohort of elderly patients who required an active treatment.

METHODS

Data from 110 consecutive patients treated with PGC for localized PCa were collected. All patients underwent the same standardized follow-up with serum-PSA level and digital rectal examination. Prostate MRI and eventual re-biopsy were performed at twelve months after cryotherapy or in case of suspicion of recurrence. Biochemical recurrence was defined according to Phoenix criteria (PSA nadir + 2 ng/ml). Kaplan-Meier curves and Multivariable Cox Regression analyses were used to predict disease progression, biochemical recurrence- (BCS) and additional treatment-free survival (TFS).

RESULTS

Median age was 75 years (IQR 70-79). PGC was performed in 54 (49.1%) patients with low-risk PCa, 42 (38.1%) with intermediate risk and 14 (12.8%) high risk. At a median follow-up of 36 months, we recorded a BCS and TFS of 75 and 81%, respectively. At 5 years, BCS was 68.5% and CRS 71.5%. High-risk prostate cancer was associated with lower TFS and BCS curves when compared with low-risk group (all p values < .03). A PSA reduction < 50% between preoperative level and nadir resulted as an independent failure predictor for all outcomes evaluated (all p values < .01). Age was not associated with worse outcomes.

CONCLUSIONS

PGC could be a valid treatment for low- to intermediate PCa in elderly patients, when a curative approach is suitable in terms of life expectancy and quality of life.

Guidelines of guidelines: focal therapy for prostate cancer, is it time for consensus?

OBJECTIVE

To provide a summary and discussion of international guidelines, position statements and consensus statements in relation to focal therapy (FT) for prostate cancer (PCa).

METHODS

The European Association of Urology-European Association of Nuclear Medicine-European Society for Radiotherapy and Oncology-European Society of Urogential Radiology-International Society of Urological Pathology-International Society of Geriatric Oncology and American Urological Association-American Society for Radiation Oncology-Society of Urologic Oncology guidelines were interrogated for recommendations for FT. PubMed and Ovid Medline were searched for consensus statements. Only studies in English since 2015 were included. Reference lists of the included articles were also interrogated and a manual search for studies was also performed.

RESULTS

Our results showed a lack of long-term randomised data for FT. International Urological guidelines emphasised the need for more high-quality clinical trials with robust oncological and toxicity outcomes. Consensus and positions statements were heterogenous.

CONCLUSION

A globally accepted guideline for FT planning, technique and follow-up are still yet to be determined. Well-designed studies with long-term follow-up and robust clinical and toxicity endpoints are needed to improve our understanding of FT and create uniform guidelines to streamline management and follow-up.

Partial Gland Ablation of Prostate Cancer: Effects of Repeat Treatment

OBJECTIVE

To evaluate the near-term clinical and pathological effects of repeat partial gland ablation (PGA) in men with intermediate-risk prostate cancer (PCa).

MATERIALS AND METHODS

One hundred seventy men with focal lesions of PCa (all GG2 or GG3) underwent PGA with high-intensity focused ultrasound (HIFU) or cryotherapy (CRYO) in prospective trials. Residual PCa in or near the ablation zone was found in 37 men after a first PGA; 30 went on to receive a second PGA and were the subjects of study. At 3 timepoints, baseline and 6 months after first and second ablations, quality-of-life (QOL) questionnaires (IIEF, IPSS) and MRI-guided biopsies (MRGB) were performed. Biopsies were targeted and systematic at baseline and in follow-up, comprehensively about the ablation zone.

RESULTS

All 30 patients completed QOL questionnaires and 26 had MRGB at the 3 timepoints. Mean QOL scores were not significantly different from the baseline after the first or second PGA. No operative complications were encountered; and "decisional regret" was reported in only 2/29 men after the repeat ablation. A decrease in semen volume was reported by 25% of patients. Repeat ablation was successful (absence of csPCa on MRGB) in 14/26 (53%) of men. PSA levels decreased and MRI lesions resolved after ablations, but neither was a reliable predictor of biopsy outcomes.

CONCLUSION

When initial PGA fails, repeat PGA is a reasonable consideration, because in near-term follow-up, secondary procedures appear to be safe, causing only minimal detriment to urinary and sexual function, with csPCa becoming undetectable by MRGB in approximately half the patients.

Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging to Detect Residual Prostate Cancer Following Irreversible Electroporation-A Multicenter Validation Study

BACKGROUND

Accurate monitoring following focal treatment of prostate cancer (PCa) is paramount for timely salvage treatment or retreatment.

OBJECTIVE

To evaluate the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) to detect residual PCa in the short-term follow-up of focal treatment with irreversible electroporation (IRE) using transperineal or transrectal template ± targeted biopsies.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective international multicenter study of men with biopsy-proven PCa, treated with focal IRE, and followed by mpMRI (index-test) and template biopsies (reference-test) between February 2013 and January 2021, was conducted.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mpMRI were calculated for in- and outfield residual disease based on two definitions of significant PCa: University College London (UCL) 1-International Society of Urological Pathology (ISUP) ≥3 or ISUP ≥1 with maximum cancer core length (MCCL) ≥6 mm, and UCL2-ISUP ≥2 or ISUP ≥1 with MCCL ≥4 mm.

RESULTS AND LIMITATIONS

A total of 303 patients from five focal therapy centers were treated with primary IRE. The final analysis was performed on 217 men (median age 67, median prostate-specific antigen 6.2, 81% ISUP 2/3) who underwent both mpMRI and template biopsies. Multiparametric MRI missed 38/57 (67%) positive biopsy locations (UCL1) in 22 patients. Sensitivity, specificity, PPV, and NPV of mpMRI to detect whole gland residual disease (UCL1) were 43.6% (95% confidence interval [CI]: 28-59), 80.9% (95% CI: 75-86), 33.3% (95% CI: 21-47), and 86.7% (95% CI: 81-91), respectively. Based on UCL2, sensitivity, specificity, PPV, and NPV were 35.8% (95% CI: 25-48), 82.0% (95% CI: 75-88), 47.1% (95% CI: 34-61), and 74.1% (95% CI: 67-80), respectively. Limitations are the retrospective nature and short follow-up.

CONCLUSIONS

The diagnostic accuracy of mpMRI to detect residual clinically significant PCa following IRE was low. Follow-up template biopsies should be performed, regardless of mpMRI results.

PATIENT SUMMARY

We investigated the accuracy of magnetic resonance imaging (MRI) to detect residual prostate cancer after treatment with irreversible electroporation. The accuracy of MRI is insufficient, and we emphasize the importance of confirmatory prostate biopsies.

Is hemi-gland focal LDR brachytherapy as effective as whole-gland treatment for unilateral prostate cancer?

PURPOSE

The Hemi-Ablative Prostate Brachytherapy (HAPpy) trial evaluated hemi-gland (HG) low-dose-rate prostate brachytherapy (LDR-PB) as a focal approach to control unilateral localized prostate cancer and reduce treatment-related toxicity at 2-years postimplant. Herewith we present further outcomes with a minimum of 5 years post-implant follow-up.

METHODS AND MATERIALS

Outcomes of 30 HG implants and 362 whole-gland (WG) brachytherapy controls were monitored with IPSS, urinary Quality-of-Life (QoLU), GI component of EORTC-PR25 (QoLB), and IIEF-5 instruments, and PSA values. The median (range) follow-up for HG and WG cases was 72 (60-96) months and 84 (24-144) months respectively.

RESULTS

The IPSS was significantly reduced in HG relative to WG patients and trends indicating improved bowel QoL and erectile function were observed. The mean of change in PSA from baseline to last follow-up was -5.6 and -6.5 in HG and WG respectively (p = 0.1). The mean time to nadir was 4.2 and 4.8 years in HG and WG respectively (p = 0.06). Over time PSA in HG patients mirrored the sustained decline observed in WG cases but levels were higher by an average 0.5 ng/ml over WG controls (p < 0.001). Treatment failure occurred in 2 (6.7%) HG patients and in 20 (5.5%) WG cases. Five-year relapse-free survival was 97% in both groups (p = 0.7).

CONCLUSIONS

At 5 years postimplant HG LDR-PB was as effective as WG treatment for control of unilateral localized prostate cancer with moderate improvement in treatment-related symptoms. Importantly, PSA is a valuable marker to assess disease control in this form of focal therapy.

Assessment after focal therapy: what is the latest?

PURPOSE OF REVIEW

To review assessment after focal therapy (FT) in the context of developments from the past two years.

RECENT FINDINGS

With a paucity of high-quality studies, recent findings are primarily reliant on results from institutional-based cohorts and reports of expert consensus. Notably, oncologic treatment failure should be further stratified into recurrence in the in-field or out-of-field ablation zone, and both regions should be surveilled postoperatively. Monitoring primarily consists of periodic evaluations of prostate-specific antigen (PSA) testing and magnetic resonance imaging, with histologic sampling needed to confirm suspicion of recurrence. Recent investigations into PSA derivatives, contrast-enhanced ultrasound, and prostate-specific membrane antigen imaging have shown preliminary promise. Although postablation functional outcomes are generally accepted to be excellent, they are limited by the wide range of patient-reported measures, variability in individual practice, and low questionnaire completion rates.

SUMMARY

There is still a need for high-level, long-term data to inform exact standardized protocols to manage patients after FT. A multifaceted approach is required to surveil patients and identify those at risk of recurrence. Embracing shared responsibility between the patient and clinician to fastidiously monitor the infield and out-of-field ablation zones postoperatively is critical to maximize oncologic outcomes.

Applications of Focused Ultrasound in the Treatment of Genitourinary Cancers

Simple Summary

Cancer is a prevalent disease globally, and conventional treatment options have been associated with substantial morbidity for patients. The unique acoustic properties and biological effects of focused ultrasound have been investigated for use as an alternative treatment option for various forms of cancer with lower associated morbidity than standard treatments. The objective of our review was to assess the current state and various applications of focused ultrasound for the treatment of genitourinary cancers, including prostate, kidney, bladder, penile, and testicular malignancies. Current research demonstrates that focused ultrasound-based focal therapy shows promise for the treatment of localized prostate and kidney cancer, and the effect of ultrasound on cell membranes may increase the efficacy of chemotherapeutics and radiotherapy. Focused ultrasound-based treatment modalities should continue to be investigated as an alternative or complementary treatment option for cancer patients.

Abstract

Traditional cancer treatments have been associated with substantial morbidity for patients. Focused ultrasound offers a novel modality for the treatment of various forms of cancer which may offer effective oncological control and low morbidity. We performed a review of PubMed articles assessing the current applications of focused ultrasound in the treatment of genitourinary cancers, including prostate, kidney, bladder, penile, and testicular cancer. Current research indicates that high-intensity focused ultrasound (HIFU) focal therapy offers effective short-term oncologic control of localized prostate and kidney cancer with lower associated morbidity than radical surgery. In addition, studies in mice have demonstrated that focused ultrasound treatment increases the accuracy of chemotherapeutic drug delivery, the efficacy of drug uptake, and cytotoxic effects within targeted cancer cells. Ultrasound-based therapy shows promise for the treatment of genitourinary cancers. Further research should continue to investigate focused ultrasound as an alternative cancer treatment option or as a complement to increase the efficacy of conventional treatments such as chemotherapy and radiotherapy.

Role of multiparametric MRI in long-term surveillance following focal laser ablation of prostate cancer

OBJECTIVE

Determine the multiparametric magnetic resonance imaging (mpMRI) appearance of the prostate following focal laser ablation (FLA) for PCa and to identify imaging characteristics associated with recurrent disease.

METHODS

Retrospective analysis of patients who underwent FLA for low-intermediate risk PCa between 2010 and 2014 was performed. Early (median 4 months) and late mpMRI (median 49 months) follow-up were qualitatively assessed for T₂-weighted, dynamic contrast enhanced (DCE) and diffusion weighted imaging (DWI) appearances and also compared to corresponding PSA values and biopsy results.

RESULTS

55 cancers were treated in 54 men (mean age 61.0 years). Early mpMRI was performed in 30 (54.5%) patients while late follow-up mpMRI in 42 (84%). Ill-defined scarring with and without atrophy at the treatment site were the most common appearances. In patients with paired MRI and biopsy, one of four patients with clinically significant PCa on biopsy (≥GG2 or≥6 mm GG1) showed hyperenhancement or restricted diffusion at early follow-up. At late follow-up, positive biopsies were seen in 5/8 (63%) cases with hyperenhancement and 5/6 (83%) cases with restricted diffusion at the treatment site. PSA change was not associated with biopsy results at either time point.

CONCLUSION

mpMRI is able to document the morphological and temporal changes following focal therapy. It has limited ability to detect recurrent disease in early months following treatment. Late-term mpMRI is sensitive at identifying patients with recurrent disease. Small sample size is, however, a limitation of the study.

ADVANCES IN KNOWLEDGE

Implementing MRI in follow-up after FT may be useful in predicting residual or recurrent PCa and therefore provide reliable outcome data.

Preclinical evaluation of a clinical prototype transrectal diffuse optical tomography system for monitoring photothermal therapy of focal prostate cancer

SIGNIFICANCE

Our work demonstrates in preclinical models that continuous-wave transrectal diffuse optical tomography (TRDOT) can be used to accurately monitor photothermal therapy (PTT) and, in particular, the progression of the photocoagulation boundary toward the rectum. When used in patients, this should prevent rectal damage during PTT, thereby achieving maximum treatment efficacy while ensuring safety, using a technology platform suitable for wide dissemination.

AIM

We aim to validate that TRDOT measurements analyzed using a shape-based image-reconstruction algorithm (SBDOT) allow localization of the photocoagulation boundary during PTT within ±1  mm toward the rectum in the transverse plane.

APPROACH

TRDOT measurements were performed in tissue-simulating phantoms, ex vivo tissues, and an in vivo canine prostate model. The accuracy and sensitivity of reconstructing the size and location of the coagulation zone were determined, based on changes in the tissue absorption and reduced scattering coefficients upon photocoagulation. The reconstruction also yields the native and coagulated tissue optical properties.

RESULTS

The TRDOT measurements and SBDOT reconstruction algorithm were confirmed to perform sufficiently well for clinical translation in PTT monitoring, recovering the location of the coagulation boundary within ±1  mm compared to the true value as determined by direct visualization postexcision and/or MRI.

CONCLUSIONS

Implementing previously described TRDOT instrumentation and SBDOT image reconstruction in different tissue models confirms the potential for clinincal translation, including required refinements of the system and reconstruction algorithm.

Reducing the number of systematic biopsy cores in the era of MRI targeted biopsy-implications on clinically-significant prostate cancer detection and relevance to focal therapy planning

BACKGROUND

The optimal number of systematic biopsy cores in the era of multi-parametric MRI targeted biopsy remains unclear, especially on its impact of focal therapy planning. Our objective is to investigate the impact of reducing the number of systematic cores on prostate cancer detection in the era of MRI-US fusion targeted biopsy and as well as its relevance in template planning for focal therapy.

MATERIALS AND METHODS

A retrospective analysis of 398 consecutive men who underwent both systematic saturation (~24 cores) and MRI-US fusion targeted biopsy was performed. Four reduced-core systematic biopsy strategies (two-thirds, half, one-third and one-quarter systematic cores) were modelled and the detection rates of clinically-significant prostate cancer (csPCa defined as grade group ≥2) were compared to that of a full systematic biopsy using McNemar's test. Focal therapy treatment plans were made based on positive cores on combined (targeted and systematic) biopsy and the various reduced-cores strategies to compare the proportion who had a change in treatment plan.

RESULTS

csPCa was detected in 42% (168/398) of this patient cohort. Non-targeted systematic saturation biopsy had a 21% (83/398) csPCa detection rate. Our four strategies reduced the mean number of non-targeted systematic cores from 21.8 to 14.5, 10.9, 7.3 and 5.4 cores and their csPCa detection rates were significantly decreased to 16%, 13%, 9% and 8% respectively (all p < 0.05). Compared to the reduced-core strategies, a full systematic saturation biopsy resulted in change to the focal therapy treatment plan in 12% (2/3 cores), 19% (1/2 cores), 24% (1/3 cores) and 29% (1/4 cores) of the time (p = 0.0434).

CONCLUSIONS

Reducing the number of systematic biopsies when performing an MRI-targeted biopsy leads to reduced detection of csPCa and alter the treatment plans for focal therapy, possibly limiting its oncological efficacy.

Minimally Invasive Procedures in the Diagnosis and Treatment of Localized Prostate Cancer: an Interventional Radiologist's Perspective

PURPOSE OF REVIEW

Minimal invasive procedures, including targeted biopsy (TB) and focal therapy (FT), are increasingly used in diagnosis and treatment of localized prostate cancer. Here, we review the current role of these procedures, from a perspective of an interventional radiologist.

RECENT FINDINGS

TB is an established part of current guidelines for diagnosis of PCa. Several modalities of FT are gaining prevalence in recent years, as a tissue-preserving alternative for definitive treatment of localized PCa. FT is currently at early research stages, offered to selected patients in clinical trials settings. TB and FT are minimally invasive procedures used by multidisciplinary teams for diagnosis and treatment of localized PCa.

Acute and subacute prostate MRI findings after MRI-guided transurethral ultrasound ablation of prostate cancer

BACKGROUND

Magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (TULSA) is an emerging method for treatment of localized prostate cancer (PCa). TULSA-related subacute MRI findings have not been previously characterized.

PURPOSE

To evaluate acute and subacute MRI findings after TULSA treatment in a treat-and-resect setting.

MATERIAL AND METHODS

Six men with newly diagnosed MRI-visible and biopsy-concordant clinically significant PCa were enrolled and completed the study. Eight lesions classified as PI-RADS 3-5 were focally ablated using TULSA. One- and three-week follow-up MRI scans were performed between TULSA and robot-assisted laparoscopic prostatectomy.

RESULTS

TULSA-related hemorrhage was detected as a subtle T1 hyperintensity and more apparent T2 hypointensity in the MRI. Both prostate volume and non-perfused volume (NPV) markedly increased after TULSA at one week and three weeks after treatment, respectively. Lesion apparent diffusion coefficient values increased one week after treatment and decreased nearing the baseline values at the three-week MRI follow-up.

CONCLUSION

The optimal timing of MRI follow-up seems to be at the earliest at three weeks after treatment, when the post-procedural edema has decreased and the NPV has matured. Diffusion-weighted imaging has little or no added diagnostic value in the subacute setting.

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.

Oncological and Functional Outcomes of Patients Undergoing Individualized Partial Gland Cryoablation of the Prostate: A Single-Institution Experience

Objectives: We aim at reporting the functional and oncological outcomes in men with localized prostate cancer who underwent individualized partial gland cryoablation of the prostate by using validated quality-of-life instruments. Methods: We retrospectively reviewed our cryosurgery database between July 2003 and September 2019 for men who were treated with individualized partial gland cryoablation of the prostate at our tertiary care center. Baseline and periodic urinary and sexual function surveys were administered throughout the post-treatment period. Results: A total of 82 men were included in the study. Median follow-up was 28 months (interquartile range: 10.5-59.3 months). A total of 71 men underwent primary individualized partial gland cryoablation, whereas 11 men underwent salvage partial gland ablation. Failure-free survival at 1 to 5 years was 98%, 89%, 84%, 75%, and 75% in the primary therapy group, and 100%, 80%, and 40% in the salvage group at 1 to 3 years, respectively. In the primary therapy group, all 71 patients remained free of pads at 3 months and throughout the follow-up period. Men who had undergone primary focal cryoablation had a higher post-treatment International Index of Erectile Function (IIEF) score, followed by men treated with primary hemi-cryoablation and primary subtotal cryoablation. The American Urological Association (AUA) symptom scores decreased regardless of the type of partial gland ablation performed, with subtotal ablation having the lowest score compared with hemiablation and focal cryoablation. No patient developed a fistula in the primary group, and 1 (9%) patient developed a fistula in the salvage group. Conclusion: Individualized partial gland cryoablation of the prostate is able to achieve excellent oncological and functional outcomes in select men with localized prostate cancer.

Prostate minimally invasive procedures: complications and normal vs. abnormal findings on multiparametric magnetic resonance imaging (mpMRI)

Minimally invasive alternatives to traditional prostate surgery are increasingly utilized to treat benign prostatic hyperplasia and localized prostate cancer in select patients. Advantages of these treatments over prostatectomy include lower risk of complication, shorter length of hospital stay, and a more favorable safety profile. Multiparametric magnetic resonance imaging (mpMRI) has become a widely accepted imaging modality for evaluation of the prostate gland and provides both anatomical and functional information. As prostate mpMRI and minimally invasive prostate procedure volumes increase, it is important for radiologists to be familiar with normal post-procedure imaging findings and potential complications. This paper reviews the indications, procedural concepts, common post-procedure imaging findings, and potential complications of prostatic artery embolization, prostatic urethral lift, irreversible electroporation, photodynamic therapy, high-intensity focused ultrasound, focal cryotherapy, and focal laser ablation.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Conventional radical versus focal treatment for localised prostate cancer: a propensity score weighted comparison of 6-year tumour control

BACKGROUND

For localised prostate cancer, focal therapy offers an organ-sparing alternative to radical treatments (radiotherapy or prostatectomy). Currently, there is no randomised comparative effectiveness data evaluating cancer control of both strategies.

METHODS

Following the eligibility criteria PSA < 20 ng/mL, Gleason score ≤ 7 and T-stage ≤ T2c, we included 830 radical (440 radiotherapy, 390 prostatectomy) and 530 focal therapy (cryotherapy, high-intensity focused ultrasound or high-dose-rate brachytherapy) patients treated between 2005 and 2018 from multicentre registries in the Netherlands and the UK. A propensity score weighted (PSW) analysis was performed to compare failure-free survival (FFS), with failure defined as salvage treatment, metastatic disease, systemic treatment (androgen deprivation therapy or chemotherapy), or progression to watchful waiting. The secondary outcome was overall survival (OS). Median (IQR) follow-up in each cohort was 55 (28-83) and 62 (42-83) months, respectively.

RESULTS

At baseline, radical patients had higher PSA (10.3 versus 7.9) and higher-grade disease (31% ISUP 3 versus 11%) compared to focal patients. After PSW, all covariates were balanced (SMD < 0.1). 6-year weighted FFS was higher after radical therapy (80.3%, 95% CI 73.9-87.3) than after focal therapy (72.8%, 95% CI 66.8-79.8) although not statistically significant (p = 0.1). 6-year weighted OS was significantly lower after radical therapy (93.4%, 95% CI 90.1-95.2 versus 97.5%, 95% CI 94-99.9; p = 0.02). When compared in a three-way analysis, focal and LRP patients had a higher risk of treatment failure than EBRT patients (p < 0.001), but EBRT patients had a higher risk of mortality than focal patients (p = 0.008).

CONCLUSIONS

Within the limitations of a cohort-based analysis in which residual confounders are likely to exist, we found no clinically relevant difference in cancer control conferred by focal therapy compared to radical therapy at 6 years.

Triggers and oncologic outcome of salvage radical prostatectomy, salvage radiotherapy and active surveillance after focal therapy of prostate cancer

PURPOSE

Due to the tissue preserving approach of focal therapy (FT), local cancer relapse can occur. Uncertainty exists regarding triggers and outcome of salvage strategies.

METHODS

Patients with biopsy-proven prostate cancer (PCa) after FT for localized PCa from 2011 to 2020 at eight tertiary referral hospitals in Germany that underwent salvage radical prostatectomy (S-RP), salvage radiotherapy (S-RT) or active surveillance (AS) were reported. Prostate specific antigen (PSA) changes, suspicious lesions on mpMRI and histopathological findings on biopsy were analyzed. A multivariable regression model was created for adverse pathological findings (APF) at S-RP specimen. Kaplan-Meier curves were generated to determine oncological outcomes.

RESULTS

A total of 90 men were included. Cancer relapse after FT was detected at a median of 12 months (IQR 9-16). Of 50 men initially under AS 13 received S-RP or S-RT. In total, 44 men underwent S-RP and 13 S-RT. At cancer relapse 17 men (38.6%) in the S-RP group [S-RT n = 4 (30.8%); AS n = 3 (6%)] had ISUP > 2. APF (pT ≥ 3, ISUP ≥ 3, pN + or R1) were observed in 23 men (52.3%). A higher ISUP on biopsy was associated with APF [p = 0.006 (HR 2.32, 97.5% CI 1.35-4.59)] on univariable analysis. Progression-free survival was 80.4% after S-RP and 100% after S-RT at 3 years. Secondary therapy-free survival was 41.7% at 3 years in men undergoing AS. Metastasis-free survival was 80% at 5 years for the whole cohort.

CONCLUSION

With early detection of cancer relapse after FT S-RP and S-RT provide sufficient oncologic control at short to intermediate follow-up. After AS, a high secondary-therapy rate was observed.

Defining prostate cancer size and treatment margin for focal therapy: does intralesional heterogeneity impact the performance of multiparametric MRI?

OBJECTIVES

To evaluate the impact of intralesional heterogeneity on the performance of multiparametric magnetic resonance imaging (mpMRI) in determining cancer extent and treatment margins for focal therapy (FT) of prostate cancer.

PATIENTS AND METHODS

We identified men who underwent primary radical prostatectomy for organ- confined prostate cancer over a 3-year period. Cancer foci on whole-mount histology were marked out, coding low-grade (LG; Gleason 3) and high-grade (HG; Gleason 4-5) components separately. Measurements of entire tumours were grouped according to intralesional proportion of HG cancer: 0%, <50% and ≥50%; the readings were corrected for specimen shrinkage and correlated with matching lesions on mpMRI. Separate measurements were also taken of HG cancer components only, and correlated against entire lesions on mpMRI. Size discrepancies were used to derive the optimal tumour size and treatment margins for FT.

RESULTS

There were 122 MRI-detected cancer lesions in 70 men. The mean linear specimen shrinkage was 8.4%. The overall correlation between histology and MRI dimensions was r = 0.79 (P < 0.001). Size correlation was superior for tumours with high burden (≥50%) compared to low burden (<50%) of HG cancer (r = 0.84 vs r = 0.63; P = 0.007). Size underestimation by mpMRI was more likely for larger tumours (51% for >12 mm vs 26% for ≤12 mm) and those containing HG cancer (44%, vs 20% for LG only). Size discrepancy analysis suggests an optimal tumour size of ≤12 mm and treatment margins of 5-6 mm for FT. For tumours ≤12 mm in diameter, applying 5- and 6-mm treatment margins would achieve 98.6% and 100% complete tumour ablation, respectively. For tumours of all sizes, using the same margins would ablate >95% of the HG cancer components.

CONCLUSIONS

Multiparametric MRI performance in estimating prostate cancer size, and consequently the treatment margin for FT, is impacted by tumour size and the intralesional heterogeneity of cancer grades.

Utilization of focal therapy for patients discontinuing active surveillance of prostate cancer: Recommendations of an international Delphi consensus

BACKGROUND

With the advancement of imaging technology, focal therapy (FT) has been gaining acceptance for the treatment of select patients with localized prostate cancer (CaP). We aim to provide details of a formal physician consensus on the utilization of FT for patients with CaP who are discontinuing active surveillance (AS).

METHODS

A 3-stage Delphi consensus on CaP and FT was conducted. Consensus was defined as agreement by ≥80% of physicians. An in-person meeting was attended by 17 panelists to formulate the consensus statement.

RESULTS

Fifty-six respondents participated in this interdisciplinary consensus study (82% urologist, 16% radiologist, 2% radiation oncology). The participants confirmed that there is a role for FT in men discontinuing AS (48% strongly agree, 39% agree). The benefit of FT over radical therapy for men coming off AS is: less invasive (91%), has a greater likelihood to preserve erectile function (91%), has a greater likelihood to preserve urinary continence (91%), has fewer side effects (86%), and has early recovery post-treatment (80%). Patients will need to undergo mpMRI of the prostate and/or a saturation biopsy to determine if they are potential candidates for FT. Our limitations include respondent's biases and that the participants of this consensus may not represent the larger medical community.

CONCLUSIONS

FT can be offered to men coming off AS between the age of 60 to 80 with grade group 2 localized cancer. This consensus from a multidisciplinary, multi-institutional, international expert panel provides a contemporary insight utilizing FT for CaP in select patients who are discontinuing AS.

The role of prostate-specific antigen in light of new scientific evidence: An update in 2020

OBJECTIVE

To review and update the latest scientific evidence gathered in recent years regarding prostate-specific antigen (PSA) for better implementation into routine clinical practice.

EVIDENCE ACQUISITION

Analysis of the available evidence on the current role of PSA, based on the experience of an expert panel in the subject under analysis.

EVIDENCE SYNTHESIS

Currently, PSA cannot be considered only as a guide for the presence or absence of prostate cancer. This determination can also help the urologist to decide on the most convenient treatment for a patient with benign prostatic hypertrophy (BPH) as a criterion for disease progression, and it can also suggest the suspicious existence of a prostatic tumor when there is PSA rise of>0.3 ng/ml over the level reached 6 months after having initiated treatment with 5-alpha-reductase inhibitor. However, the limits of this PSA rise with derivatives of alternative 5-alpha-reductase (5-ARI) inhibitors to dutasteride are controversial. Moreover, PSA is a key factor for the follow-up of patients with prostate adenocarcinoma at any stage who have received treatment (surgery, radiotherapy or focal therapies, hormone therapy), it acts as a guide to identify biochemical recurrence, to suspect the existence of local or distant recurrence, as well as to propose or discard adjuvant treatments. Finally, the role of PSA as a screening tool has been recently reinforced, demonstrating increased mortality rates or the existence of more aggressive cases of prostate cancer in those countries where the use of this tool has declined.

CONCLUSIONS

We present new data about the current role of PSA in the management of patients treated for BPH and/or prostate cancer that should be implemented into routine clinical practice, with special emphasis on the relevant role of this biomarker in the screening and follow-up of prostate cancer, as well as in the progression of BPH in dutasteride treatment.

PI-RADS Version 2.1: A Critical Review, From the AJR Special Series on Radiology Reporting and Data Systems

PI-RADS version 2.1 updates the technical parameters for multiparametric MRI (mpMRI) of the prostate and revises the imaging interpretation criteria while maintaining the framework introduced in version 2. These changes have been considered an improvement, although some issues remain unresolved, and new issues have emerged. Areas for improvement discussed in this review include the need for more detailed mpMRI protocols with optimization for 1.5-T and 3-T systems; lack of validation of revised transition zone interpretation criteria and need for clarifications of the revised DWI and dynamic contrast-enhanced imaging criteria and central zone (CZ) assessment; the need for systematic evaluation and reporting of background changes in signal intensity in the prostate that can negatively affect cancer detection; creation of a new category for lesions that do not fit into the PI-RADS assessment categories (i.e., PI-RADS M category); inclusion of quantitative parameters beyond size to evaluate lesion aggressiveness; adjustments to the structured report template, including standardized assessment of the risk of extraprostatic extension; development of parameters for image quality and performance control; and suggestions for expansion of the system to other indications (e.g., active surveillance and recurrence).

Acceptance, Indications and Chances of Focal Therapy in Localized Prostate Cancer: A Real-World Perspective of Urologists in Germany

Purpose: Focal therapy (FT) became a frequently discussed treatment strategy of localized prostate cancer (PCa), but the acceptance and evaluation of FT by practicing urologists are still unclear. Methods: A 25-item anonymized online questionnaire (SurveyMonkey^®) was compiled by the German Society of Residents in Urology Academics Prostate Cancer Working Group and sent to the members of the German association of Urology. Logistic regression analysis was performed to determine parameters for suggestion FT. Results: Two hundred ten urologists (median age 49 years) participated, from which 72% stated PCa as their main treatment focus. Ninety-nine percent of urologists were aware of and 54% wanted to improve their knowledge about FT. Sixty-five percent do not treat PCa with FT. FT is seen as an alternative to active surveillance and radiotherapy/radical prostatectomy by 66% and 37%, respectively. Regarding FT treatment strategies, 35% and 45% would treat all or all significant PCa foci, respectively, whereas 19% would treat mainly the index foci. Currently, 27% believe that FT will be an option as standard treatment in future, but 48% would not suggest FT to their patients, owing to an absence of evidence and insufficient diagnostic tools for proper patient selection today. Suggesting FT to patients is associated with self-performing FT (odds ratio [OR] 2.88, 95% confidence interval [CI] 1.31-6.31) and believing in FT as a standard treatment in future (OR 9.05, 95% CI 6.68-22.30) (both p < 0.01). Conclusion: FT has currently no wide acceptance in German practicing urologists, mainly attributable to an absence of evidence for FT superiority compared to standard treatments.

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.

Standardized Nomenclature and Surveillance Methodologies After Focal Therapy and Partial Gland Ablation for Localized Prostate Cancer: An International Multidisciplinary Consensus

BACKGROUND

Focal therapy (FT) and partial gland ablation (PGA) are quickly adopted by urologists and radiologists as an option for the management of localized prostate cancer.

OBJECTIVE

To find consensus on a standardized nomenclature and to define a follow-up guideline after FT and PGA for localized prostate cancer in clinical practice.

DESIGN, SETTING, AND PARTICIPANTS

A review of the literature identified controversial topics in the field of FT. Online questionnaires were distributed to experts during three rounds, with the goal to achieve consensus on debated topics. The consensus project was concluded with a face-to-face meeting in which final conclusions were formulated.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Controlled feedback of responses of previous rounds were summarized and returned to the participants allowing them to re-evaluate their decisions. The level of agreement to achieve consensus on a topic was set at 80%.

RESULTS AND LIMITATIONS

Sixty-five experts participated in this interdisciplinary consensus study (72% urologists; 28% radiologists). The experts propose the use of the herein standardized nomenclature for ablative procedures. After FT/PGA, the following tests should be performed to assess treatment outcomes: prostate-specific antigen (PSA), imaging, biopsies, and functional outcome assessment. Although not a reliable marker for treatment failure, PSA should be measured every 3 mo in the 1st year and every 6 mo thereafter. Magnetic resonance imaging is the preferred image modality and should be performed at 6 and 18 mo after treatment. A systematic 12-core transrectal ultrasound-guided biopsy combined with a targeted biopsy of the treated area should be performed 6-12 mo after treatment. Functional outcomes should be obtained 3-6 mo after treatment for the first time and until stability is attained.

CONCLUSIONS

The panel recommends the use of the proposed nomenclature and follow-up protocols to generate reliable data supporting a broader implementation of FT as a standard of care for select patients with localized prostate cancer.

PATIENT SUMMARY

In this report, we present expert opinion on the use of a standardized nomenclature, and surveillance methodologies after focal therapy and partial gland ablation for localized prostate cancer.

Focal therapy, time to join the multi-disciplinary team discussion?

Organ preserving management is common place in renal cancer, breast cancer and many other solid organ tumours. Current strategies in managing intermediate risk prostate cancer include either whole gland treatment, in the form of radical radiotherapy or radical prostatectomy, or active surveillance. The former is associated with significant post-treatment functional morbidity, whilst the latter associated with the burden of surveillance activity and patient anxiety. Focal therapy would logically fit as a middle ground for suitable patients in whom treatment would be recommended, but where much better functional outcomes may be possible. Ideally this comes without restricting the successful prevention of harm from the cancer. Historically limitations in developing tissue preserving focal therapy strategies in prostate cancer, were due to inaccuracies in tumour characterisation prior to treatment and during follow up. Consequently for example many patients undergoing an active surveillance strategy were being upgraded and upstaged within a short period. Recently high level evidence supporting the use of MRI and targeted biopsies, in particular the PROMIS and PRECISION trials have strengthened clinician confidence in accurate disease characterisation, thus making focal therapy to become a more feasible management option. With improved diagnostic strategies and the publication of reassuring medium term oncological and functional outcomes after focal therapy for intermediate risk prostate cancer, has the time come to require consideration of focal therapy within our multi-disciplinary team (MDT) meetings and with patients? In this review we will consider patient selection and the evidence for the various focal ablation options as well as the surveillance of these patients after treatment. The forthcoming trials to determine comparative effectiveness will be discussed.

Early oncological control following partial gland cryo-ablation: a prospective experience specifying reflex MRI guided biopsy of the ablation zone

BACKGROUND

Several consensus statements recommend serial serum prostate-specific antigen (PSA), multi parametric magnetic resonance imaging (mpMRI), and prostate biopsy following partial gland ablation. We determined the rate of persistent in-field disease following primary partial gland cryo-ablation and whether PSA or mpMRI are reliable predictors of in-field disease persistence.

METHODS

Between March 2017 and July 2019, subjects meeting eligibility criteria for partial gland cryoablation were enrolled into an IRB approved outcomes registry. PSA, mpMRI, and prostate biopsy (four cores targeting the ablation zone + six ipsilateral systematic cores) were performed per protocol 6 months following intervention. Binary logistic regression was employed to calculate odds ratio (OR) of PSA decrease, and suspicious mpMRI effect on cancer persistence. The performance of mpMRI for predicting in-field persistence of PCa was evaluated by area under the receiver operation characteristics curve (AUC).

RESULTS

Of the 83 eligible men undergoing partial gland cryoablation, 70 (84.3%) underwent 6-month protocol prostate biopsy. Five (7.1%) biopsies exhibited any in-field disease persistence. Only one (1.4%) of these cancers was Gleason grade > 1. Neither PSA decrease or suspicious mpMRI reliably predicted cancer persistence, with OR of 1.6 (0.25-8.6) and 1.5 (0.02-1.3), respectively. AUC of mpMRI for predicting in-field disease persistence was 0.554.

CONCLUSIONS

In this cohort of patients undergoing partial gland cryo-ablation, the incidence of persistent disease was low. PSA and mpMRI were not reliable predictors of in-field disease persistence. Based on these data, consideration may be given to deferring early follow-up biopsy in appropriate patients.

Making a case "against" focal therapy for intermediate-risk prostate cancer

INTRODUCTION

Focal therapy (FT) for localized prostate cancer (PCa) is a promising treatment strategy. Although, according to guidelines, it should be regarded as an experimental option, its introduction into clinical practice has occurred at an accelerated speed. It is, thus, crucial for Urologists to understand FT limitations and potential drawbacks that may derive from its use.

METHODS

We performed a literature search of peer-reviewed English language articles using Pubmed and the words "focal therapy" AND "prostate cancer" to identify relevant articles. Web search was complemented by manual search.

RESULTS

From a biological perspective, in contrast with the index lesion theory, which still needs to be better supported, PCa is a multifocal and multiclonal entity. Also, the effects of FT on PCa microenvironment are unclear. From a clinical perspective, patient selection is still not precisely defined. Even when all variables potentially decreasing mpMRI and biopsy accuracy are optimized, up to one out of two men may be incorrectly selected for FT, leaving a significant proportion of clinically significant PCa (csPCa) untreated. Underestimation of PCa volume and variant histologies are other additional mpMRI potential limitations. No RCTs have been performed against the standard of care to support FT. There is absence of long-term results and FT series reaching medium-term follow-up have non-optimal oncological control with significant re-treatment needs. When PCa recurs/persists after FT, little is known about the appropriate management strategies and their outcomes. Finally, the optimal follow-up scheme post-FT remains unclear.

CONCLUSIONS

Several arguments are present against the use of FT for localized PCa. Studies are needed to overcome current limitations and support FT before it can be included as part of the standard management of prostate cancer.

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.

Whole and hemi-gland cryoablation for primary localized prostate cancer: Short and medium-term oncological and functional outcomes

INTRODUCTION

To compare oncological, functional and post-operative outcomes of hemi (HC) vs. whole gland (WGC) cryoablation as first line treatment of localized prostate cancer.

MATERIAL AND METHOD

Sixty-six consecutive patients undertaking whole-gland cryoablation (WGC=40) or hemi-cryoablation (HC=26) in a tertiary referral centre between 2010 and 2018 were included. All patients had a low-intermediate risk prostate cancer according to D'Amico risk classification. Hemi-ablation was proposed in case of biopsy and prostate MRI proven unilateral prostate cancer. Primary endpoint was Cryotherapy Failure for which 3 definitions were considered and compared: 1) biochemical failure (> PSA nadir+≥ 2 ng/mL), 2) positive prostate re-biopsy with Gleason score ≥ 7, 3) initiation of further prostate cancer treatment.

RESULTS

Median patients age at treatment was 74 [42-81] vs. 76 [71-80] years in WGC vs. HC group, respectively (p=.08). Low and intermediate D'Amico risk group were 15% and 85% vs. 23% and 77% (p=.75), respectively. Median follow- up time was 41 [1.5-99.0] vs. 27 [0.9-93] months (p=.03). Four-years cryotherapy failure free survival in WGC vs. HC were 69% vs. 53% with definition 1 (p=.24), 82% vs. 80% with definition 2 (p=.95), 83% vs. 77% with definition 3 (p=.73). Early and 1-year urinary continence were 60% and 83% in WGC vs. 72% and 83% in HC (p=.26). De novo impotency after cryotherapy was 75% vs. 46% (p=.33) in WGC vs. HC.

CONCLUSIONS

In our cohort of highly selected patients with unilateral low/intermediate risk PCa, hemi-cryoablation may provide similar oncological outcomes and less early complications compared to whole-gland cryoablation.

Histopathological evaluation of prostate specimens after thermal ablation may be confounded by the presence of thermally-fixed cells

Purpose: Prostate cancer can be eradicated with heat exposure. However, high and rapid temperature elevations may cause thermofixation giving the appearance of viable tissue. The purpose was to characterize the immunoprofile and evaluate the viability of prostate regions with suspected thermofixation. Methods and materials: A prospective, ethics-approved and registered study (NCT03350529) enrolled six patients with MRI-visible, biopsy-concordant prostate cancer to undergo lesion-targeted MRI-guided transurethral ultrasound ablation (TULSA) followed by radical prostatectomy at 3 weeks, to evaluate the accuracy and efficacy of TULSA with whole-mount histology as a reference standard. If ambiguity about complete necrosis within the ablated region remained after hematoxylin-eosin staining, viability was assessed by immunohistochemistry. Treatment day MRI-thermometry and 3-week contrast-enhanced MRI post-TULSA were examined to assess ablation success and correlation with histopathology. Results: One patient presented with an apparently viable subregion inside the ablated area, surrounded by necrosis on H&E staining, located where temperature was highest on MRI-thermometry and tissues completely devascularized on MRI. Immunoprofile of the apparently viable tissue revealed changes in staining patterns suggesting thermofixation; the most significant evidence was the negative cytokeratin 8 staining detected with Cam5.2 antibody. A comprehensive literature review supports these observations of thermofixation with similar findings in prostate and other tissues. Conclusion: Thermally-fixed cells can sustain morphology on H&E staining. Misinterpretation of treatment failure may occur, if this phenomenon is not recognized and immunohistochemistry performed. Based on the previous literature and the current study, Cam5.2 staining for cytokeratin 8 appears to be a practical and reliable tool for distinguishing thermally-fixed from viable cells.

Prostate Multiparametric Magnetic Resonance Imaging Features Following Partial Gland Cryoablation

OBJECTIVE

To assess the qualitative and quantitative changes on prostate multiparametric magnetic resonance imaging (mpMRI) following partial gland ablation (PGA) with cryotherapy and correlate with histopathology.

METHODS

We used 3D Slicer to generate prostate models and segment ipsilateral (treated) and contralateral peripheral and transition zones in 10 men who underwent MRI/transrectal ultrasound fusion-guided PGA during 2017-2018. Pre- and post-PGA volumes of prostate segments were compared. Post-PGA mpMRI were categorized according to PI-RADS v2 and treatment response on mpMRI was assessed in a manner similar to the radiology evaluation framework following liver lesion ablation.

RESULTS

Median volume of ipsilateral peripheral and transition zones decreased from 10.9 mL and 13.0 mL to 7.2 mL and 10.8 mL (P = .005), respectively. Median volume of contralateral peripheral and transition zones also decreased from 12.1 mL and 12.5 mL to 9.9 mL to 10.4 mL (P = .005), respectively. Five men had clinically significant disease (Grade group ≥2) on post-PGA biopsy (3 within treatment field and 2 outside). Of the men with clinically significant prostate cancer, mpMRI revealed PI-RADS 3 lesions in 2. However, the treatment response framework did not detect residual disease.

CONCLUSION

PGA results in asymmetrical and significant reductions in prostate volume. Our results highlight the need for a separate assessment framework to enable standardization of the interpretation and reporting of post-PGA surveillance mpMRI. Moreover, our findings have significant implications for MRI-targeted surveillance biopsy following PGA with cryotherapy.

Gold nanoshell-localized photothermal ablation of prostate tumors in a clinical pilot device study

Biocompatible gold nanoparticles designed to absorb light at wavelengths of high tissue transparency have been of particular interest for biomedical applications. The ability of such nanoparticles to convert absorbed near-infrared light to heat and induce highly localized hyperthermia has been shown to be highly effective for photothermal cancer therapy, resulting in cell death and tumor remission in a multitude of preclinical animal models. Here we report the initial results of a clinical trial in which laser-excited gold-silica nanoshells (GSNs) were used in combination with magnetic resonance-ultrasound fusion imaging to focally ablate low-intermediate-grade tumors within the prostate. The overall goal is to provide highly localized regional control of prostate cancer that also results in greatly reduced patient morbidity and improved functional outcomes. This pilot device study reports feasibility and safety data from 16 cases of patients diagnosed with low- or intermediate-risk localized prostate cancer. After GSN infusion and high-precision laser ablation, patients underwent multiparametric MRI of the prostate at 48 to 72 h, followed by postprocedure mpMRI/ultrasound targeted fusion biopsies at 3 and 12 mo, as well as a standard 12-core systematic biopsy at 12 mo. GSN-mediated focal laser ablation was successfully achieved in 94% (15/16) of patients, with no significant difference in International Prostate Symptom Score or Sexual Health Inventory for Men observed after treatment. This treatment protocol appears to be feasible and safe in men with low- or intermediate-risk localized prostate cancer without serious complications or deleterious changes in genitourinary function.

Do contemporary imaging and biopsy techniques reliably identify unilateral prostate cancer? Implications for hemiablation patient selection

BACKGROUND

Hemiablation is a less morbid treatment alternative for appropriately selected patients with unilateral prostate cancer (PCa). However, to the authors' knowledge, traditional diagnostic techniques inadequately identify appropriate candidates. In the current study, the authors quantified the accuracy for identifying hemiablation candidates using contemporary diagnostic techniques, including multiparametric magnetic resonance imaging (mpMRI) and MRI-fusion with complete systematic template biopsy.

METHODS

A retrospective analysis of patients undergoing MRI and MRI-fusion prostate biopsy, including full systematic template biopsy, prior to radical prostatectomy in a single tertiary academic institution between June 2010 and February 2018 was performed. Hemiablation candidates had unilateral intermediate-risk PCa (Gleason score [GS] of 3+4 or 4+3, clinical T classification ≤T2, and prostate-specific antigen level <20 ng/dL) on MRI-fusion biopsy and 2) no contralateral highly or very highly suspicious Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) MRI lesions. Hemiablation candidates were inappropriately selected if pathologists identified contralateral GS ≥3+4 or high-risk ipsilateral PCa on prostatectomy. The authors tested a range of hemiablation inclusion criteria and performed multivariable analysis of preoperative predictors of undetected contralateral disease.

RESULTS

Of 665 patients, 92 met primary hemiablation criteria. Of these 92 patients, 44 (48%) were incorrectly identified due to ipsilateral GS ≥3+4 tumors crossing the midline (21 patients), undetected distinct contralateral GS ≥3+4 tumors (20 patients), and/or ipsilateral high-risk PCa (3 patients) on prostatectomy. The rate of undetected contralateral disease ranged from 41% to 48% depending on inclusion criteria. On multivariable analysis, men with anterior index tumors were found to be 2.4 times more likely to harbor undetected contralateral GS ≥3+4 PCa compared with men with posterior lesions (P < .05).

CONCLUSIONS

Clinicians and patients must weigh the risk of inadequate oncologic treatment against the functional benefits of hemiablation. Further investigation into methods for improving patient selection for hemiablation is necessary.

Use of MRI-Guided Biopsy for Selection and Follow-up of Men Undergoing Hemi-gland Cryoablation of Prostate Cancer

OBJECTIVE

To investigate safety, efficacy, and quality of life impact of hemi-gland cryotherapy for clinically-significant prostate cancer (CaP), when patient selection and follow-up includes MRI-guided biopsy.

METHODS

Twenty-nine men with unilateral CaP (all clinically significant with prostate volume <60 cc) were enrolled in a prospective observational trial of hemi-gland cryotherapy. Mean patient age was 68.7 years. Median prostate-specific antigen (PSA) was 6.6 ng/mL. MRI-guided biopsy (3T-MRI, Artemis US fusion) was used for diagnosis and repeated at 6-month follow-up in all men. Treatment was under general anesthesia using the BTG/Galil system. Validated questionnaires were used to determine effects of treatment on urinary and sexual function and quality of life.

RESULTS

Cryotherapy was completed satisfactorily in all 29 cases in <60 minutes with no intraoperative complications. Significant decreases in PSA (median decrease 5.6 ng/mL) and PSA density (median decrease 0.14 ng/mL/cc) were observed (P < .01). At 6 months, 23 patients (79%) demonstrated no residual cancer on follow-up MRI-guided biopsy of the treated side. Three patients (10%) revealed micro-residual disease. Three patients (10%) had residual cancer and underwent further treatment. Ipsilateral MRI lesions were present before treatment in 26 patients and after treatment in only 2, reflecting the gross ablative effect; however, MRI showed disappearance of lesions in 4 patients with residual tumor on biopsy. The single complication was 1 case of transient urinary retention; 85% of men who were sexually active continued without change after treatment. Voiding function was unchanged.

CONCLUSION

Hemi-gland cryoablation for clinically-significant CaP is well-tolerated, and when patients are selected and followed by MRI/US fusion biopsy, cancer control appears promising at 6 months.