Long-term Outcomes of Focal Cryotherapy for Low- to Intermediate-risk Prostate Cancer: Results and Matched Pair Analysis with Active Surveillance

Oncological results and cancer control definition in focal therapy for Prostate Cancer: a systematic review

INTRODUCTION

Focal therapy (FT) is a promising alternative to whole-gland treatments for Localized Prostate Cancer. Ten different FT modalities have been described in literature. However, FT is not yet recommended by the International Guidelines, due to the lack of robust data on Oncological Outcomes. The objective of our Narrative Review is to evaluate the oncological profile of the available FT modalities and to offer a comprehensive overview of the definitions of Cancer Control for FT.

MATERIAL AND METHODS

Literature search was performed on 21^st February 2023 using PubMed, EMBASE, and Scopus, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA). Articles reporting whole gland-treatments were excluded. All articles reporting oncological outcomes were included.

RESULTS

One-hundred-twenty-four studies, reporting data on more than 8000 patients treated with FT, were included. Overall, 40 papers were on High Intensity Focal Ultrasound (HIFU), 24 on Focal Cryotherapy, 13 on Irreversible Electroporation (IRE), 11 on Focal brachytherapy, 10 on Focal Laser Ablation (FLA), 8 on Photo-Dynamic Therapy (PDT), 3 on Microwave ablation, 3 on Robotic Partial Prostatectomy, 2 on bipolar Radio Frequency Ablation (bRFA), 1 on Prostatic Artery Embolization (PAE) and 9 comparative papers. Overall, the Biochemical Recurrence (BCR) rate ranged from 0% (Focal Brachytherapy) to 67.5% (HIFU); the Salvage treatment rate ranged from 1% (IRE) to 54% (HIFU) considering re-treatment with FT and from 0% (Focal Brachytherapy) to 66.7% considering standard Radical Treatments. There is no univocal definition of Cancer Control, however the "Phoenix criteria" for BCR were the most commonly used.

CONCLUSIONS

FT is a promising alternative treatment for localized prostate cancer in terms of Oncological Outcomes, however there is a wide heterogeneity in the definition of cancer control, the reporting of oncological outcomes and a lack of high-quality clinical trials. Solid comparative studies with standard treatments and an unambiguous consensus on how to describe Cancer Control in the field of Focal Therapy are needed.

Cryotherapy for partial gland ablation of prostate cancer: Oncologic and safety outcomes

BACKGROUND

Partial gland ablation (PGA) is a new option for treatment of prostate cancer (PCa). Cryotherapy, an early method of PGA, has had favorable evaluations, but few studies have employed a strict protocol using biopsy endpoints in men with clinically significant prostate cancer (csPCa).

METHODS

143 men with unilateral csPCa were enrolled in a prospective, observational trial of outpatient PGA-cryotherapy. Treatment was a 2-cycle freeze of the affected prostate part. Participants were evaluated with MRI-guided biopsy (MRGB) at baseline and at 6 months and 18 months after treatment. Absence of csPCa upon MRGB was the primary endpoint; quality-of-life at baseline and at 6 months after treatment was assessed by EPIC-CP questionnaires in the domains of urinary and sexual function.

RESULTS

Of the 143 participants, 136 (95%) completed MRGB at 6 months after treatment. In 103/136 (76%), the biopsy revealed no csPCa. Of the 103, 71 subsequently had an 18-month comprehensive biopsy; of the 71 with 18-month biopsies, 46 (65%) were found to have no csPCa. MRI lesions became undetectable in 96/130 (74%); declines in median serum PSA levels (6.9 to 2.5 ng/mL), PSA density (0.15 to 0.07), and prostate volume (42 to 34cc) were observed (all p < 0.01). Neither lesion disappearance on MRI nor PSA decline correlated with biopsy outcome. Urinary function was affected only slightly and sexual function moderately.

CONCLUSION

In the near to intermediate term, partial gland ablation with cryotherapy was found to be a safe and moderately effective treatment of intermediate-risk prostate cancer. Eradication of cancer was better determined by MRI-guided biopsy than by MRI or PSA.

Focal High-Intensity Focused Ultrasound vs. Active Surveillance for ISUP Grade 1 Prostate Cancer: Medium-Term Results of a Matched-Pair Comparison

INTRODUCTION/BACKGROUND

Only 1 randomized controlled trial has compared focal therapy and active surveillance (AS) for the low-risk prostate cancer (PCa). We investigated whether focal HIFU (fHIFU) yields oncologic advantages over AS for low-risk PCa.

MATERIALS AND METHODS

We included 2 non-randomized prospective series of 132 (fHIFU) and 421 (AS) consecutive patients diagnosed with ISUP 1 PCa between 2008 and 2018. A matched pair analysis was performed to decrease potential bias. Study main outcomes were freedom from radical treatment (RT) or androgen-deprivation therapy (ADT), treatment-free survival (TFS), time to metastasis, and overall survival (OS).

RESULTS

Median fHIFU follow-up was 50 months (interquartile range, 29-84 months). Among matched variables, no major differences were recorded except for AS having more suspicious digital rectal examination findings (P = .0074) and recent enrollment year (P = .0005). Five-year intervention-free survival from RT or ADT was higher for the fHIFU cohort (67.4% vs. 53.8%; P = .0158). Time to treatment was approximately 10 months shorter for AS than for fHIFU (time to RT, P = .0363; time to RT or ADT, P = .0156; time to any treatment, P = .0319). No differences were found in any-TFS (fHIFU, 61.4% vs. AS, 53.8%; P = .2635), OS (fHIFU, 97% vs. AS, 97%; P = .9237), or metastasis (n = 0 in fHIFU and n = 2 in AS; P = .4981). Major complications (≥ Clavien 3) were rare (n = 4), although 36.4% of men experienced complications. No relevant changes were noted in continence (P = .3949).

CONCLUSION

At a 4-year median follow-up, fHIFU for mainly low-risk PCa (ISUP grade 1) is safe, may decrease the need for radical treatment or ADT and may allow longer time to treatment compared to AS. Nonetheless, no advantages are seen in PCa progression and/or death (OS).

Focal Therapy for Prostate Cancer: The Impact on Sexual Function

Focal therapy (FT) has emerged as a potential treatment for localized prostate cancer (PCa) with encouraging functional outcomes. According to the compelling evidence based on meta-analyses and recent trials, erectile function (EF) is mostly retained at 6 and 12 months after FT when compared to baseline. These findings are consistent across different energy sources reported to date. However, overall, quality of life, including impotence, was not the endpoint for most studies. Additionally, impotency has not been consistently reported in most of the recent literature. Furthermore, confounding factors such as baseline potency and usage of phosphodiesterase 5 inhibitors (PDE5-I) were also frequently undisclosed. Long-term functional outcomes are awaited. To fully comprehend how FT affects EF, more extensive long-term randomized clinical trials using EF as a primary outcome are needed.

The use of advanced imaging in guiding the further investigation and treatment of primary prostate cancer

In the era of precision medicine, oncological imaging techniques are advancing at a rapid pace, particularly molecular imaging with promising new targets for prostate cancer (PC) such as gastrin releasing peptide receptors (GRPR) along the established and indispensable prostate specific membrane antigen (PSMA). As PC is characterized by heterogenous tumor biology ranging from indolent to aggressive disease, distinguishing clinically significant tumors from indolent disease is critical. Multiparametric MRI- and PET-targeted prostate biopsies mitigate the shortcomings and risks of standard systematic template biopsy by identifying more significant cancers.Focal treatment for localized disease is a minimally invasive approach that targets the index tumor - the lesion of the highest grade - while sparing the surrounding healthy tissue. Real-time MRI-guidance and thermal control with MR-thermometry, improves treatment accuracy and results in lower rates of functional side effects. PET imaging could be an useful tool to assess response to treatment compared to invasive prostate biopsies.In this comprehensive review, we focus on the image-guided detection and treatment of localized primary prostate cancer, its current status and future perspectives.

Systematic Review of Focal and Salvage Cryotherapy for Prostate Cancer

Cryotherapy is one of the recognised ablative modalities for both primary and salvage therapy for prostate cancer. It presents an alternative, less invasive treatment for an organ-confined disease, improved preservation of surrounding tissue and a more suitable option for patients who are unfit for radical prostatectomy. Nevertheless, the currently available literature is relatively too scarce to provide definite conclusions regarding the treatment outcomes in cryotherapy. The present study aimed to review current oncological and survival outcomes in cryotherapy for primary and recurrent prostate cancer. Furthermore, this study aimed to establish the complications and functional outcomes of cryotherapy for prostate cancer. A literature search was performed on the PubMed, Cochrane and Google Scholar databases. Current guidelines and recommendations from the European Association of Urology were also reviewed. The search keywords used included ‘Cryotherapy, Prostate Cancer’, ‘Cryoablation, Prostate Cancer’ and ’Cryosurgery, Focal Prostate Cancer’. Truncations and Boolean operators were used with the keywords. All relevant studies from after 2015, including abstracts and non-English research assessing oncological and functional outcomes and complications, were included. Twenty-six studies consisting of 11,228 patients were reviewed. Fifteen studies assessed the outcomes of primary cryotherapy, whereas 11 studies reported the outcomes in salvage therapy. The patient's age ranged 55-85 years, and the pre-procedural prostate-specific antigen (PSA) ranged 0.01-49.33 ng/mL. A total of 2031 patients were classified to be at low risk, 2,995 were at moderate risk and 253 were at high risk on the D’Amico prostate cancer risk classification system. Follow-ups ranged from 9.0 to 297.6 months. The disease-specific survival rate was 65.5%-100.0%, overall survival was 61.3%-99.1%, the PSA nadir was 0.01-2.63 ng/mL and the overall biochemical recurrence rate was 15.4%-62.0%. The complications included erectile dysfunction (3.7%-88.0%), urinary retention (2.13%-25.30%) and bladder neck stricture/stenosis (3.0%-16.7%). The functional assessment showed a mixture of improved, unchanged or worsened post-procedural outcomes in primary therapy. This systematic review did not find significant differences in the cancer-specific, overall and biochemical-free survival rate between the primary and salvage cryotherapy cohorts. The most common complications encountered in both cohorts were erectile dysfunction, urinary incontinence, lower urinary tract/bladder neck stricture and infection. More prospective and double-arm studies are critically needed to provide guidance on the careful selection of patient cohorts for cryotherapy, whether for curative or salvage intent.

The SAFE Pilot Trial—SAlvage Focal Irreversible Electroporation—For Recurrent Localized Prostate Cancer: Rationale and Study Protocol

Introduction

Currently, the majority of prostate cancer (PCa) recurrences after non-surgical first-line treatment are managed with androgen-deprivation therapy (ADT). Salvage radical prostatectomy (sRP) is a curative alternative to ADT but yields significant morbidity. Preliminary evidence from focal salvage treatments shows similar oncological control but lower morbidity compared to sRP. Among available ablative focal energies, irreversible electroporation (IRE) is a treatment modality that proved promising, especially in treating apical lesions, where PCa most often recurs. Our aim is to test the safety of salvage IRE for recurrent PCa.

Methods

We performed a single-arm pilot feasibility study (IDEAL stage 2a): SAFE, SAlvage Focal irreversible Electroporation for recurrent localized PCa. Twenty patients with biopsy-proven PCa recurrence after primary non-surgical (radiation or ablation) treatment were included. All men will undergo mpMRI ± targeted biopsies, pre-operative PSMA-PET staging before inclusion and sIRE. Outcomes will be evaluated through internationally validated questionnaires and morbidity scales. All men will undergo a control biopsy at one year.

Results

Primary objectives were the evaluation of the safety of sIRE (and patients’ quality of life) after treatment. Secondary objectives were the evaluation of functional outcomes, namely, continence and erectile function changes and evaluation of short-term oncological efficacy.

Conclusions

SAFE is the second pilot study to evaluate sIRE and the first one performed according to the most recent diagnostic and staging imaging standards. sIRE may provide a curative option for recurrent PCa together with lower comorbidities compared to sRP.

Clinical and pathologic characteristics to select patients for focal therapy or partial gland ablation of nonmetastatic prostate cancer

PURPOSE OF REVIEW

Focal therapy or partial gland ablation for nonmetastatic prostate cancer is gaining popularity not just as an alternative to active surveillance, but as an acceptable alternative to whole gland therapy in appropriate cases. This review summarizes recent evidence to help select patients for optimal outcomes.

RECENT FINDINGS

Recommendations by expert panels have become less conservative with each meeting. As experience with older modalities for focal therapy grows, newer modalities continue to be introduced. We are now in a position to offer personalized treatment pathway considering nuances of each focal therapy modality.

SUMMARY

The ideal case for focal therapy should be an MRI visible significant lesion (PIRADS score ≥ 3), with a positive biopsy for significant cancer (Gleason grade group 2-3) in the corresponding targeted biopsy area, and insignificant or absent disease in the nontarget random biopsy areas. Multifocal disease can also be selectively treated. Salvage focal ablation is an attractive treatment option for radio-recurrent or index focal therapy failure cases.

Focal prostate cancer therapy in the era of multiparametric MRI: a review of options and outcomes

BACKGROUND

The goal of prostate cancer focal therapy is to achieve oncologic control while reducing the rate of adverse events associated with whole-gland treatments. Numerous focal therapy modalities are currently available with early data demonstrating highly variable rates of cancer control and preservation of sexual/urinary function.

METHODS

All English language clinical trial publications evaluating various focal therapies for localized prostate cancer were reviewed. The literature search was limited to studies from the modern era of MRI-guided treatment, as MRI is hypothesized to improve tumor localization and targeting. Primary outcomes were post-treatment cancer-free rates, in-field/out-of-field recurrence rates, and rates of conversion to radical therapy. Secondary outcomes were related to functional status and adverse events.

RESULTS

Numerous focal therapies were identified with clinical data including high-intensity focused ultrasound, transurethral ultrasound ablation, focal laser ablation, focal cryotherapy, irreversible electroporation, and photodynamic therapy. Recurrence rates among all technologies were low to moderate (0-51%) and rates of freedom from radical treatment were highly variable (46-98%). Rates of erectile dysfunction and incontinence generally ranged from 0 to 44% and 0 to 12%, respectively, with variability between focal therapy modalities. Caution should be exercised when comparing studies as outcomes are strongly associated with patient selection. No individual focal therapy is currently recommended by society guidelines. Randomized controlled trials are ongoing in search of a standard of care.

CONCLUSION

For localized MRI-visible prostate cancer, early clinical trial data demonstrate that focal therapy can provide good to moderate cancer control while having preferable side effect profiles compared to whole-gland treatments. While current studies do not make head-to-head comparisons between technologies, early data suggest a potential for these technologies to provide adequate cancer control in a well-selected patient population. The oncologic outcomes of some focal therapies appear promising; however, longer-term follow-up data are needed to assess the durability of early outcomes.

Oral administration of E-type prostanoid (EP) 1 receptor antagonist suppresses carcinogenesis and development of prostate cancer via upregulation of apoptosis in an animal model

Prostaglandin E2 plays an important role in carcinogenesis and malignant potential of prostate cancer (PC) cells by binding to its specific receptors, E-type prostanoid (EP) receptors. However, anti-carcinogenic effects of the EP receptor antagonist are unclear. In this study, we used a mouse model of PC. The mice were provided standard feed (control) or feed containing the EP1 receptor antagonist and were sacrificed at 10, 15, 30, and 52 weeks of age. Apoptosis was evaluated by immunohistochemical analysis using a cleaved caspase-3 assay. The incidence of cancer in the experimental group was significantly lower than that in the control group at 15, 30, and 52 weeks of age. The percentage of poorly differentiated PC cells was significantly lower in the experimental group than in the control group at 30 and 52 weeks of age. The percentage of apoptotic cells in the experimental group was significantly higher than that in the control group at 15, 30, and 52 weeks of age. These findings indicate that feeding with the addition of EP1 receptor antagonist delayed PC progression via the upregulation of apoptosis. We suggest that the EP1 receptor antagonist may be a novel chemopreventive agent for PC.