Evaluation of post-ablation mpMRI as a predictor of residual prostate cancer after focal high intensity focused ultrasound (HIFU) ablation

Combining Percentage Prostate-Specific Antigen Reduction and Multiparametric Magnetic Resonance Imaging to Reduce Unnecessary Biopsy After Focal Therapy With High-Intensity Focused Ultrasound for Prostate Cancer

OBJECTIVES

To test the feasibility of combining percentage prostate-specific antigen (PSA) reduction and multiparametric magnetic resonance imaging (mpMRI) to determine the clinical scenario in which follow-up biopsy could be avoided after focal therapy (FT) with high-intensity focused ultrasound (HIFU) for prostate cancer.

METHODS

We reviewed 90 men treated with FT. Percentage PSA reduction was calculated by PSA nadir within postoperative 6 months. mpMRI was arranged at postoperative 6 months, followed by routine biopsy. Logistic regression analyses were performed to identify predictors for clinically significant prostate cancer (csPC) on follow-up biopsy. Receiver operating characteristic curve analysis was done to assess the area under the curve (AUC). The diagnostic performance of percentage PSA reduction and mpMRI to predict csPC was also calculated.

RESULTS

Eight patients had csPC recurrence. Percentage PSA reduction and Prostate Imaging-Reporting and Data System (PI-RADS) ≥ 3 at postoperative 6 months were predictors for csPC (p = 0.033 and p = 0.02, respectively). The AUC of mpMRI, percentage PSA reduction, and their combination were 0.95, 0.816, and 0.982, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of PSA reduction < 70% and PI-RADS ≥ 3 to predict csPC were 87.5%, 69.5%, 21.9%, 98.3%, and 87.5%, 96.3%, 70%, 98.8%, respectively. Using the criteria of PSA reduction < 70% or PI-RADS ≥ 3 to determine biopsy candidates could avoid 60% of biopsies, without missing csPC.

CONCLUSION

For patients whose PSA reduction > 70% and PI-RADS < 3, we suggested avoiding routine biopsy at 6 months after FT with HIFU.

The Use of PI-FAB Score in Evaluating mpMRI After Focal Ablation of Prostate Cancer: Is It Reliable? Inter-Reader Agreement in a Tertiary Care Referral University Hospital

BACKGROUND/PURPOSE

to assess the inter-reader agreement of the PIFAB (Prostate Imaging after Focal Ablation) score, a new MRI-based standardized system for evaluating post-focal therapy prostate mpMRI, among radiologists in a single large cohort of patients treated with focal therapy (HIFU) in a tertiary care referral University Hospital.

METHODS

In total, 68 consecutive patients who underwent HIFU were included in this single-center retrospective observational study. A total of 109 post-HIFU follow-up mpMRIs were evaluated by three radiologists with varying levels of experience (12, 8, and 3 years, respectively). All patients underwent their first follow-up mpMRI at 6 months post-treatment, with 30 patients receiving additional evaluations at 18 months and 11 at 30 months.

RESULTS

The patients had a mean age of 70.6 ± 8.31 years, a mean pre-treatment PSA (prostate-specific antigen) of 7.85 ± 1.21 ng/mL, and a mean post-treatment PSA of 4.64 ± 4.2 ng/mL. The inter-reader agreement for PI-FAB among the three radiologists showed a Gwet's AC2 value of 0.941 (95% confidence interval: 0.904-0.978, p < 0.0001). For the most experienced radiologist, at the 6-month follow-up 64 (94.14%) patients were scored as PI-FAB 1, 1 (1.47%) as PI-FAB 2, and 3 (4.41%) as PI-FAB 3. At the 18-month and 30-month follow-ups all patients were scored as PI-FAB 1 (no suspicion of recurrence).

CONCLUSIONS

Our study demonstrates excellent inter-reader agreement among radiologists with varying levels of experience, confirming that the PI-FAB score is highly reproducible when evaluating post-treatment mpMRI scans. The low rate of PI-FAB 2 and PI-FAB 3 lesions observed at the first follow-up, coupled with the absence of significant recurrence in subsequent evaluations, suggests that HIFU is a reliable technique for prostate cancer treatment in selected patients.

The role of the radiologist in the prostate cancer multidisciplinary conference

The broad range of disease aggressiveness together with imperfect screening, diagnostic, and treatment options in prostate cancer (PCa) makes medical decision-making complex. The primary goal of a multidisciplinary conference is to improve patient outcomes by combining evidence-based data and expert opinion to discuss optimal management, including for those patients with challenging presentations. The primary purpose of the genitourinary imaging specialist in the prostate cancer multidisciplinary conference is to use imaging findings to reduce uncertainty by answering clinical questions. In this review, we discuss the role and the opportunities for an imaging specialist to add value in the care of men with prostate cancer discussed at multidisciplinary conferences.

Surveillance after Focal Therapy - a Comprehensive Review

BACKGROUND

to date, no standardized, evidence-based follow-up schemes exist for the monitoring of patients who underwent focal therapy (FT) and expert centers rely mainly on their own experience and/or institutional protocols. We aimed to perform a comprehensive review of the most advantageous follow-up strategies and their rationale after FT for prostate cancer (PCa).

METHODS

a narrative review of the literature was conducted to investigate different follow-up protocols of FT for PCa. Outcomes of interest were post-ablation oncological and functional outcomes and complications.

RESULTS

Oncological success after FT was generally defined as the biopsy-confirmed absence of clinically significant PCa in the treated zone. De novo PCa in the untreated area usually reflects an inaccurate patient selection and should be treated as primary PCa. During follow-up, oncological outcomes should be evaluated with periodic PSA, multiparametric MRI and prostate biopsy. The use of PSA derivatives and new biomarkers is still controversial and therefore not recommended. The first MRI after FT should be performed between 6-12 months to avoid ablation-related artifacts and diagnostic delay in case of FT failure. Other imaging modalities, such as PSMA PET/CT scan, are promising but still need to be validated in the post-FT setting. A 12-month "for-protocol" prostate biopsy, including targeted and systematic biopsy, was generally considered the preferred biopsy method to rule out tumor persistence/recurrence. Subsequent mpMRIs and biopsies should follow a risk-adapted approach depending on the clinical scenario. Functional outcomes should be periodically assessed using validated questionnaires within the first year, when typically recover to a new baseline. Complications, despite uncommon, should be strictly monitored mainly in the first month.

CONCLUSIONS

FT follow-up is a multifaceted process involving clinical, radiological, and histological assessment. Studies evaluating the impact of different follow-up strategies and ideal timings are needed to produce standardized protocols following FT.

MRI accuracy for recurrence after partial gland ablation with HIFU for localized prostate cancer. A systematic review and meta-analysis

BACKGROUND

Prostate cancer remains the most frequently diagnosed cancer among men. High-Intensity Focused Ultrasound (HIFU) has emerged as a thermal ablative technique for partial-gland-ablation (PGA), aiming to minimize collateral damage while maximizing tumor control. Monitoring after HIFU PGA relies on serial PSA testing, multiparametric-MRI, and biopsies. The diagnostic accuracy of MRI for clinically-significant cancer(csPCa) recurrence is challenging.

OBJECTIVE

This systematic review and meta-analysis aim to evaluate the accuracy of MRI in detecting early recurrence of localized prostate cancer following HIFU PGA.

METHODS

Adhering to PRISMA guidelines, a comprehensive literature search was conducted until May 8th 2024 using MEDLINE and Scopus. The inclusion criteria encompassed randomized controlled trials and cohort studies involving men diagnosed with localized prostate cancer who had as primary treatment HIFU PGA. The primary outcome measures included the sensitivity, specificity, positive-predictive value (PPV), and negative-predictive value (NPV) of MRI for csPCa(ISUP ≥ 2) based on biopsy results. We pooled data from studies with sufficient csPCa and csPCa-free patients (≥5) post HIFU for statistical analysis.

RESULTS

Fifteen studies meet the inclusion criteria, encompassing 1093 patients and 12 studies were eligible for meta-analysis. MRI sensitivity in detecting clinically-significant prostate cancer (csPCa) recurrence post HIFU PGA varied widely (0-89%), with a pooled sensitivity of 0.52 (95% CI:0.36-0.68). Specificity ranged from 44% to 100%, with a pooled specificity of 0.81 (95% CI:0.68-0.91). The pooled NPV was 0.82 (95% CI:0.72-0.90), and the pooled PPV was 0.50 (95% CI:0.35-0.65). Three studies reported in-field diagnostic performance with sensitivities ranging from 0.42 to 0.80 and specificities from 0.45 to 0.97.

CONCLUSION

MRI accuracy for clinically-significant recurrence after partial gland ablation with HIFU for localized prostate cancer shows low diagnostic performance in the treated lobe with pooled sensitivity of 0.52 (95% CI:0.36-0.68) and specificity of 0.81 (95% CI:0.68-0.91). Limits of this review include the low number of studies reporting about site of recurrence in or out of the treated lobe.

Comparative Effectiveness of Partial Gland Cryoablation Versus Robotic Radical Prostatectomy for Cancer Control

BACKGROUND AND OBJECTIVE

There is an absence of high-level evidence comparing oncologic endpoints for partial gland ablation, and most series use prostate-specific antigen (PSA) rather than biopsy endpoints. Our aim was to compare oncologic outcomes between partial gland cryoablation (PGC) and radical prostatectomy (RP) for prostate cancer.

METHODS

This was a retrospective, single-center analysis of subjects treated with PGC (n = 98) or RP (n = 536) between January 2017 and December 2022 as primary treatment for intermediate-risk (Gleason grade group [GG] 2-3) prostate cancer. Oncologic endpoints included surveillance biopsies per protocol after PGC in comparison to serial PSA testing after RP. The primary outcome was treatment failure, defined as a need for any salvage treatment or development of metastatic disease. Treatment failure and survival analyses were conducted using Cox proportional-hazard regression and Kaplan Meier survival curves.

KEY FINDINGS AND LIMITATIONS

After applying the inclusion/exclusion criteria, the PGC (n = 75) and RP (n = 298) groups were compared. PGC patients were significantly older (71 vs 64 yr; p < 0.001), but there were no differences in PSA, biopsy GG, or treatment year between the groups. The PGC group had higher rates of treatment failures at 24 mo (33% vs 11%; p < 0.001) and 48 mo (43% vs 14%; p < 0.001). One PGC patient (2.1%) and one RP patient (0.7%) developed metastases by 48-mo follow-up (p = 0.4). On adjusted analysis, PGC was associated with a higher risk of treatment failure (hazard ratio 4.6, 95% confidence interval 2.7-7.9; p < 0.001). Limitations include observational biases associated with the retrospective study design.

CONCLUSIONS

This is the first comparative effectiveness study of cancer control outcomes for PGC versus RP. The results demonstrate an almost fivefold higher risk of treatment failure with PGC during short-term follow-up.

PATIENT SUMMARY

We compared cancer control outcomes for patients with intermediate-risk prostate cancer treated with partial gland cryoablation versus radical prostatectomy. We found that partial gland cryoablation had an almost fivefold higher risk of treatment failure. Men with prostate cancer should be counseled regarding this difference in treatment failure.

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.

Focal therapy with high-intensity focused ultrasound for prostate cancer: 3-year outcomes from a prospective trial

OBJECTIVE

To assess the oncological and functional outcomes of focal high-intensity focused ultrasound (HIFU) in treating localised prostate cancer (PCa), a 3-year prospective study was undertaken using periodic post-ablation saturation biopsies.

PATIENTS AND METHODS

Men with two or fewer lesions of grade group (GG) ≤3 PCa were eligible for participation. Additional criteria included a prostate-specific antigen (PSA) level of ≤15 ng/mL, clinical T1c-T2, and a life expectancy of ≥10 years. The primary endpoint was failure-free survival (FFS), defined as absence of clinically significant PCa (csPCa) in- or out-of-field on protocol-mandated saturation biopsy, no whole-gland or systemic salvage treatment, PCa metastasis, or PCa-related death. Results are reported using two distinct definitions of csPCa: (i) the presence of any GG ≥2 and (ii) any GG ≥3 or core involvement of ≥6 mm. Secondary endpoints were functional patient-reported outcome measures addressing urinary, sexual, and bowel function.

RESULTS

A total of 91 patients were included: six (7%) with GG1 and 85 (93%) with GG ≥2. In all, 83 (91%) underwent at least one follow-up biopsy. Biopsy attendance at 6, 12, and 36 months was 84%, 67%, and 51%, respectively. The FFS at these time points for any GG ≥2 PCa was 79% (95% confidence interval [CI] 80-88%), 57% (95% CI 48-69%) and 44% (95% CI 34-56%), respectively. Using the second definition, FFS were 88% (95% CI 81-95%), 70% (95% CI 61-81%) and 65% (95% CI 55-77%), respectively. The 3-year cancer-specific survival was 100%, and freedom from metastasis was 99%. Magnetic resonance imaging (MRI) (negative predictive value of up to 89%, 95% CI 84-93%) and relative decrease of PSA values (P = 0.4) performed poorly in detecting residual disease. Urinary and bowel assessment returned to baseline questionnaire scores within 3 months. In all, 17 (21%) patients reported meaningful worsening in erectile function. A significant decrease of PCa related anxiety was observed.

CONCLUSIONS

Focal HIFU treatment for localised PCa shows excellent functional outcomes with half of the patients remaining cancer-free after 3 years. Whole-gland treatment was avoided in 81%. Early follow-up biopsies are crucial to change or continue the treatment modality at the right time, while the use of MRI and PSA in detecting PCa recurrence is uncertain.

High-intensity focused ultrasound with visually directed power adjustment for focal treatment of localized prostate cancer: systematic review and meta-analysis

PURPOSE

To characterize patient outcomes following visually directed high-intensity focused ultrasound (HIFU) for focal treatment of localized prostate cancer.

METHODS

We performed a systematic review of cancer-control outcomes and complication rates among men with localized prostate cancer treated with visually directed focal HIFU. Study outcomes were calculated using a random-effects meta-analysis model.

RESULTS

A total of 8 observational studies with 1,819 patients (median age 67 years; prostate-specific antigen 7.1 mg/ml; prostate volume 36 ml) followed over a median of 24 months were included. The mean prostate-specific antigen nadir following visually directed focal HIFU was 2.2 ng/ml (95% CI 0.9-3.5 ng/ml), achieved after a median of 6 months post-treatment. A clinically significant positive biopsy was identified in 19.8% (95% CI 12.4-28.3%) of cases. Salvage treatment rates were 16.2% (95% CI 9.7-23.8%) for focal- or whole-gland treatment, and 8.6% (95% CI 6.1-11.5%) for whole-gland treatment. Complication rates were 16.7% (95% CI 9.9-24.6%) for de novo erectile dysfunction, 6.2% (95% CI 0.0-19.0%) for urinary retention, 3.0% (95% CI 2.1-3.9%) for urinary tract infection, 1.9% (95% CI 0.1-5.3%) for urinary incontinence, and 0.1% (95% CI 0.0-1.4%) for bowel injury.

CONCLUSION

Limited evidence from eight observational studies demonstrated that visually directed HIFU for focal treatment of localized prostate cancer was associated with a relatively low risk of complications and acceptable cancer control over medium-term follow-up. Comparative, long-term safety and effectiveness results with visually directed focal HIFU are lacking.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

The Association of Tissue Change and Treatment Success During High-intensity Focused Ultrasound Focal Therapy for Prostate Cancer

BACKGROUND

Tissue preservation strategies have been increasingly used for the management of localized prostate cancer. Focal ablation using ultrasound-guided high-intensity focused ultrasound (HIFU) has demonstrated promising short and medium-term oncological outcomes. Advancements in HIFU therapy such as the introduction of tissue change monitoring (TCM) aim to further improve treatment efficacy.

OBJECTIVE

To evaluate the association between intraoperative TCM during HIFU focal therapy for localized prostate cancer and oncological outcomes 12 mo afterward.

DESIGN, SETTING, AND PARTICIPANTS

Seventy consecutive men at a single institution with prostate cancer were prospectively enrolled. Men with prior treatment, metastases, or pelvic radiation were excluded to obtain a final cohort of 55 men.

INTERVENTION

All men underwent HIFU focal therapy followed by magnetic resonance (MR)-fusion biopsy 12 mo later. Tissue change was quantified intraoperatively by measuring the backscatter of ultrasound waves during ablation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Gleason grade group (GG) ≥2 cancer on postablation biopsy was the primary outcome. Secondary outcomes included GG ≥1 cancer, Prostate Imaging Reporting and Data System (PI-RADS) scores ≥3, and evidence of tissue destruction on post-treatment magnetic resonance imaging (MRI). A Student's t - test analysis was performed to evaluate the mean TCM scores and efficacy of ablation measured by histopathology. Multivariate logistic regression was also performed to identify the odds of residual cancer for each unit increase in the TCM score.

RESULTS AND LIMITATIONS

A lower mean TCM score within the region of the tumor (0.70 vs 0.97, p = 0.02) was associated with the presence of persistent GG ≥2 cancer after HIFU treatment. Adjusting for initial prostate-specific antigen, PI-RADS score, Gleason GG, positive cores, and age, each incremental increase of TCM was associated with an 89% reduction in the odds (odds ratio: 0.11, confidence interval: 0.01-0.97) of having residual GG ≥2 cancer on postablation biopsy. Men with higher mean TCM scores (0.99 vs 0.72, p = 0.02) at the time of treatment were less likely to have abnormal MRI (PI-RADS ≥3) at 12 mo postoperatively. Cases with high TCM scores also had greater tissue destruction measured on MRI and fewer visible lesions on postablation MRI.

CONCLUSIONS

Tissue change measured using TCM values during focal HIFU of the prostate was associated with histopathology and radiological outcomes 12 mo after the procedure.

PATIENT SUMMARY

In this report, we looked at how well ultrasound changes of the prostate during focal high-intensity focused ultrasound (HIFU) therapy for the treatment of prostate cancer predict patient outcomes. We found that greater tissue change measured by the HIFU device was associated with less residual cancer at 1 yr. This tool should be used to ensure optimal ablation of the cancer and may improve focal therapy outcomes in the future.