Cryosurgery would be An Effective Option for Clinically Localized Prostate Cancer: A Meta-analysis and Systematic Review

Epigenetics as a Key Factor in Prostate Cancer

Nowadays, prostate cancer is one of the most common forms of malignant neoplasms in men all over the world. Against the background of increasing incidence, there is a high mortality rate from prostate cancer, which is associated with an inadequate treatment strategy. Such a high prevalence of prostate cancer requires the development of methods that can ensure early detection of the disease, improve the effectiveness of treatment, and predict the therapeutic effect. Under these circumstances, it becomes crucial to focus on the development of effective diagnostic and therapeutic approaches. Due to the development of molecular genetic methods, a large number of studies have been accumulated on the role of epigenetic regulation of gene activity in cancer development, since it is epigenetic changes that can be detected at the earliest stages of cancer development. The presence of epigenetic aberrations in tumor tissue and correlations with drug resistance suggest new therapeutic approaches. Detection of epigenetic alterations such as CpG island methylation, histone modification, and microRNAs as biomarkers will improve the diagnosis of the disease, and the use of these strategies as targets for therapy will allow for greater personalization of prostate cancer treatment.

Novel Combinatorial Approaches to Tackle the Immunosuppressive Microenvironment of Prostate Cancer

Prostate cancer (PCa) is the second-most common cancer in men worldwide and treatment options for patients with advanced or aggressive prostate cancer or recurrent disease continue to be of limited success and are rarely curative. Despite immune checkpoint blockade (ICB) efficacy in some melanoma, lung, kidney and breast cancers, immunotherapy efforts have been remarkably unsuccessful in PCa. One hypothesis behind this lack of efficacy is the generation of a distinctly immunosuppressive prostate tumor microenvironment (TME) by regulatory T cells, MDSCs, and type 2 macrophages which have been implicated in a variety of pathological conditions including solid cancers. In PCa, Tregs and MDSCs are attracted to TME by low-grade chronic inflammatory signals, while tissue-resident type 2 macrophages are induced by cytokines such as IL4, IL10, IL13, transforming growth factor beta (TGFβ) or prostaglandin E2 (PGE2) produced by Th2 cells. These then drive tumor progression, therapy resistance and the generation of castration resistance, ultimately conferring a poor prognosis. The biology of MDSC and Treg is highly complex and the development, proliferation, maturation or function can each be pharmacologically mediated to counteract the immunosuppressive effects of these cells. Herein, we present a critical review of Treg, MDSC and M2 involvement in PCa progression but also investigate a newly recognized type of immune suppression induced by the chronic stimulation of the sympathetic adrenergic signaling pathway and propose targeted strategies to be used in a combinatorial modality with immunotherapy interventions such as ICB, Sipuleucel-T or antitumor vaccines for an enhanced anti-PCa tumor immune response. We conclude that a strategic sequence of therapeutic interventions in combination with additional holistic measures will be necessary to achieve maximum benefit for PCa patients.

A Novel, Efficient, Unit Circle-Based, Method for Positioning and Operating Cryo-Surgical Probes in Convex Target Areas

A novel method for positioning and operating needle-like cryo-surgical probes in 2D convex target areas is presented. The method is based on the recorded dynamic performance of a single probe, termed "unit circle," (UC) embedded in a semi-infinite, tissue-like medium. Up to 15 cryo-probes, inserted into the same depth, are operated uniformly for 2-5 min. A predetermined number of probes are rearranged inside the target area until a "tight configuration" is obtained. The probes are initially arranged inside the target area such that the "lethal temperature" circles produced by them are tangent to its contour and to both adjacent lethal temperature circles. Subsequently, all probes are repositioned inwardly, each at a specific distance that depends on the local radius of curvature of the target area. Resulting total "defect areas"-internal and external-for a number of demonstrated cases, amounted to between 2.5% and 7.6% of the target area. The lower values of the defect areas were obtained with increasing numbers of inserted probes coupled with shorter operating times. Possible freezing damages to regions beyond the target area were reduced by up to about 30% for these cases. Similar results were obtained for a case of combined convex-concave target area, treated with additional, externally inserted, heating probes.

Cryoablation, high-intensity focused ultrasound, irreversible electroporation, and vascular-targeted photodynamic therapy for prostate cancer: a systemic review and meta-analysis

Cryoablation (CA), high-intensity focused ultrasound (HIFU), irreversible electroporation (IRE), and vascular-targeted photodynamic therapy (VTP) have been evaluated as novel strategies for selected patients with prostate cancer (PCa). We aim to determine the current status of literature regarding the clinical outcomes among these minimally invasive therapies. A systematic search of PubMed, EMBASE, and the Cochrane Library for all English literature published from January 2001 to December 2019 was conducted to identify studies evaluating outcomes of CA, HIFU, IRE or VTP on PCa. Proportionality with 95% confidence intervals (CIs) was performed using STATA version 14.0. 56 studies consisting of 7383 participants were found to report data of interest and fulfilled the inclusion criteria in the final meta-analysis. The pooled proportions of positive biopsy after procedure were 20.0%, 24.3%, 24.2%, and 36.2% in CA, HIFU, IRE and VTP, respectively. The pooled proportions of BRFS were 75.7% for CA and 74.4% for HIFU. The pooled proportions of CSS were 96.1%, 98.2%, and 97.9% for CA, HIFU, and IRE, respectively. The pooled proportions of OS were 92.8% for CA and 85.2% for HIFU. The pooled proportions of FFS were 64.7%, 90.4%, and 76.7% for CA, IRE and VTP, respectively. The pooled proportions of MFS were 92.8% for HIFU and 99.1% for IRE. This meta-analysis shows that CA, HIFU, IRE, and VTP are promising therapies for PCa patients with similar clinical outcomes. However, further larger, well-designed randomized controlled trials are required to confirm this assertion.

Percutaneous MR-guided prostate cancer cryoablation technical updates and literature review

Prostate cancer (PCa) is the most common malignant tumor in males. The benefits in terms of overall reduction in specific mortality due to the widespread use of Prostate Specific Antigen (PSA) screening and the advancements in the curative treatments (radical prostatectomy or radiotherapy) appear to have reached a plateau. There remains, however, the questions of overdiagnosis and overtreatment of such patients. Currently, the main challenge in the treatment of patients with clinically organ-confined PCa is to offer an oncologically efficient treatment with as little morbidity as possible. Amongst the arising novel curative techniques for PCa, cryoablation (CA) is the most established one, which is also included in the NICE and AUA guidelines. CA is commonly performed under ultrasound guidance with the inherent limitations associated with this technique. The recent advancements in MRI have significantly improved the accuracy of detecting and characterizing a clinically significant PCa. This, alongside the development of wide bore interventional MR scanners, has opened the pathway for in bore PCa treatment. Under MRI guidance, PCa CA can be used either as a standard whole gland treatment or as a tumor targeted one. With MR-fluoroscopy, needle guidance capability, multiplanar and real-time visualization of the iceball, MRI eliminates the inherent limitations of ultrasound guidance and can potentially lead to a lower rate of local complications. The aim of this review article is to provide an overview about PCa CA with a more specific insight on MR guided PCa CA; the limitations, challenges and applications of this novel technique will be discussed.

Percutaneous MR-guided whole-gland prostate cancer cryoablation: safety considerations and oncologic results in 30 consecutive patients

OBJECTIVE

To assess the safety and oncological efficacy of percutaneous MR-guided whole-gland prostate cancer (PCa) cryoablation (CA).

METHODS AND MATERIALS

Between July 2009 and January 2018, 30 patients (mean age 72.9 ± 5.13 years) with histologically proven, organ-confined (≤ T2cN0M0), predominantly low/intermediate-risk PCa (median Gleason score 7; mean prostate specific antigen 6.05 ± 3.74 ng ml^-1 ) underwent MR-guided whole-gland CA. Patients were selected on the basis of prior pelvic radiotherapy (n = 16; 12 for previous PCa), or contra indication/refusal of surgery or radiotherapy. Complications, local progression-free survival (LPFS) and overall survival (OS) were retrospectively investigated.

RESULTS

Eighteen [60%] patients reported procedure-related complications: 5/18 [28%] needed surgical/interventional treatments and 13 [72%] conservative or pharmacological treatment. Eleven [73%] complications were noted in the first 15 patients and 7 [47%] in the last 15 patients (p = 0.26). Mean nadir prostate specific antigen was 0.24 ± 1.5 ng ml^-1 (mean follow-up 3.8 years; range: 2 - 2915 days). Seven [23%] patients developed histologically proven local progression (mean time to recurrence 775 days, range: 172 - 2014). Mean clinical follow-up was 3.8 years (range 1-2915 days). LPFS was 92.0, 75.7 and 69.4 % at 1-, 3- and 5 year follow-up, respectively. For patients in salvage treatment, LPFS was 100%, 75%, and 75% at 1-, 3- and 5 year follow-up. OS was 100%, 94.4 and 88.5 % at 1-, 3- and 5 year follow-up respectively, with no patients dying from PCa.

CONCLUSION

Whole-gland PCa CA offers good oncological efficacy, particularly in post-radiotherapy cases. Although the complication rate is significant, the majority is minor and is managed with conservative or pharmacologic management.

ADVANCES IN KNOWLEDGE

MRI-guided whole-gland prostate cancer cryoablation offers good oncological efficacy, particularly in post-radiotherapy cases with a contained complication rate.

Functional results in the treatment of localized prostate cancer. An updated literature review

Prostate cancer is the second most frequently diagnosed cancer in men. The initial diagnosis is made in increasingly younger patients, so it seems to be essential to guarantee optimal functional results. We carried out a systematic search to define the functional results of each of the therapeutic options for localized prostate cancer. Radical prostatectomy generates a greater negative effect on urinary continence and erectile function compared to active surveillance and radiotherapy. Robotic surgery seems to offer better functional results, especially at the level of erectile function. Urinary and bowel symptoms are more pronounced after radiotherapy compared to other options. Patients must be warned of the possible functional results prior to choice of treatment.

Comparative Effectiveness of Conservative Management Compared to Cryotherapy in Localized Prostate Cancer Patients

The high frequency of treatment-related side effects for men with localized prostate cancer creates uncertainty for treatment outcomes. This study assessed the comparative effectiveness of treatment-related side effects associated with conservative management and cryotherapy in patients with localized prostate cancer. A retrospective longitudinal cohort study was conducted, using the linked data of the Surveillance, Epidemiology, and End Results and Medicare, which included patients diagnosed from 2000 through year 2013, and their Medicare claims information from 2000 through 2014. To compare the differences in baseline characteristics and treatment-related side effects between the study cohorts, χ² tests were conducted. Multivariate logistic regression was used to assess the association between treatment selection and side effects. There were 7,998 and 3,051 patients in the conservative management and cryotherapy cohort, respectively. The likelihood of erectile dysfunction, lower urinary tract obstruction, urinary fistula, urinary incontinence, and hydronephrosis was reported to be significantly lower (53%, 35%, 69%, 65%, and 36%, respectively) in the conservative management cohort. Conservative management had a lower likelihood of treatment-related side effects compared to cryotherapy. However, further research is needed to compare other significant long-term outcomes such as costs associated with these treatment choices and quality of life.

Primary cryotherapy for localised or locally advanced prostate cancer

BACKGROUND

Traditionally, radical prostatectomy and radiotherapy with or without androgen deprivation therapy have been the main treatment options to attempt to cure men with localised or locally advanced prostate cancer. Cryotherapy is an alternative option for treatment of prostate cancer that involves freezing of the whole prostate (whole gland therapy) or only the cancer (focal therapy), but it is unclear how effective this is in comparison to other treatments.

OBJECTIVES

To assess the effects of cryotherapy (whole gland or focal) compared with other interventions for primary treatment of clinically localised (cT1-T2) or locally-advanced (cT3) non-metastatic prostate cancer.

SEARCH METHODS

We updated a previously published Cochrane Review by performing a comprehensive search of multiple databases (CENTRAL, MEDLINE, EMBASE), clinical trial registries (ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform) and a grey literature repository (Grey Literature Report) up to 6 March 2018. We also searched the reference lists of other relevant publications and conference proceedings. We applied no language restrictions.

SELECTION CRITERIA

We included randomised or quasi-randomised trials comparing cryotherapy to other interventions for the primary treatment of prostate cancer.

DATA COLLECTION AND ANALYSIS

Two independent reviewers screened the literature, extracted data, and assessed risk of bias. We performed statistical analyses using a random-effects model and interpreted them according to the Cochrane Handbook for Systematic Reviews of Interventions. We rated the quality of evidence (QoE) according to the GRADE approach.

MAIN RESULTS

We included only one comparison of whole gland cryotherapy versus external beam radiotherapy, which was informed by two trials with a total of 307 randomised participants. The median age of the included studies was around 70 years. The median follow-up of included studies ranged from 100 to 105 months.Primary outcomes: we are uncertain about the effect of whole gland cryotherapy compared to radiation therapy on time to death from prostate cancer; hazard ratio (HR) of 1.00 (95% confidence interval (CI) 0.11 to 9.45; 2 trials, 293 participants; very low QoE); this would correspond to zero fewer death from prostate cancer per 1000 men (95% CI 85 fewer to 520 more). We are equally uncertain about the effect of quality of life-related urinary function and bowel function (QoL) at 36 months using the UCLA-Prostate Cancer Index score for which higher values (range: 0 to 100) reflect better quality of life using minimal clinically important differences (MCID) of 8 and 7 points, respectively; mean difference (MD) of 4.4 (95% CI -6.5 to 15.3) and 4.0 (95% CI -73.96 to 81.96), respectively (1 trial, 195 participants; very low QoE). We are also uncertain about sexual function-related QoL using a MCID of 8 points; MD of -20.7 (95% CI -36.29 to -5.11; 1 trial, 195 participants; very low QoE). Lastly, we are uncertain of the risk for major adverse events; risk ratio (RR): 0.91 (95% CI 0.47 to 1.78; 2 trials, 293 participants; very low QoE); this corresponds to 10 fewer major adverse events per 1000 men (95% CI 58 fewer to 86 more).

SECONDARY OUTCOMES

we are very uncertain about the effects of cryotherapy on time to death from any cause (HR 0.99, 95% CI 0.05 to 18.79; 2 trials, 293 participants; very low QoE), and time to biochemical failure (HR 2.15, 95% CI 0.07 to 62.12; 2 trials, 293 participants; very low QoE). Rates of secondary interventions for treatment failure and minor adverse events were either not reported in the trials, or the data could not be used for analyses.We found no trials that compared whole gland cryotherapy or focal cryotherapy to other treatment forms such as radical surgery, active surveillance, watchful waiting or other forms of radiotherapy.

AUTHORS' CONCLUSIONS

Based on very low quality evidence, primary whole gland cryotherapy has uncertain effects on oncologic outcomes, QoL, and major adverse events compared to external beam radiotherapy. Reasons for downgrading the QoE included serious study limitations, indirectness due to the use of lower doses of radiation in the comparison group than currently recommended, and serious or very serious imprecision.

The prostate cancer focal therapy

Despite prostate cancer (PCa) is the leading form of non-cutaneous cancer in men, most patients with PCa die with disease rather than of the disease. Therefore, the risk of overtreatment should be considered by clinicians who have to distinguish between patients with high risk PCa (who would benefit from radical treatment) and patients who may be managed more conservatively, such as through active surveillance or emerging focal therapy (FT). The aim of FT is to eradicate clinically significant disease while protecting key genito-urinary structures and function from injury. While effectiveness studies comparing FT with conventional care options are still lacking, the rationale supporting FT relies on evidence-based advances such as the understanding of the index lesion's central role in the natural history of the PCa and the improvement of multiparametric magnetic resonance imaging (mpMRI) in the detection and risk stratification of PCa. In this literature review, we want to highlight the rationale for FT in PCa management and the current evidence on patient eligibility. Furthermore, we summarize the best imaging modalities to localize the target lesion, describe the current FT techniques in PCa, provide an update on their oncological outcomes and highlight trends for future research.

Effects of Focal vs Total Cryotherapy and Minimum Tumor Temperature on Patient-reported Quality of Life Compared With Active Surveillance in Patients With Prostate Cancer

OBJECTIVE

To investigate the effects of focal (hemiablation) or total cryotherapy and minimum tumor temperature on patient-reported quality of life (QoL) in patients with prostate cancer.

METHODS

An Institutional Review Board-approved database was reviewed for patients who underwent cryotherapy or active surveillance (AS). QoL questionnaire responses were collected and scores were analyzed for differences between focal and total cryotherapy and between very cold (<-76°C) and moderate-cold (≥-76°C) minimum tumor temperatures.

RESULTS

A total of 197 patients responded to a total of 547 questionnaires. Focal and total cryotherapy patients had initially lower sexual function scores relative to AS (year 1 mean difference focal: -31.7, P <.001; total: -48.1, P <.001). Focal cryotherapy was associated with a more rapid improvement in sexual function. Both focal and total cryotherapy sexual function scores were not statistically significantly different from the AS cohort by postprocedural year 4. Very cold and moderate-cold temperatures led to initially lower sexual function scores relative to AS (year 1 very cold: -38.1, P <.001; moderate-cold: -30.7, P <.001). Moderate-cold temperature scores improved more rapidly than those of very cold temperature. Neither very cold nor moderate-cold temperatures had a statistically significant difference in sexual function scores relative to AS by postprocedural year 4. Urinary function and bowel habits were not significantly different between focal and total cryotherapy and between very cold and moderate-cold temperature groups.

CONCLUSION

Focal cryotherapy and moderate-cold (≥-76°C) temperature were associated with favorable sexual function relative to total cryotherapy and very cold temperature, respectively. No significant differences in urinary function or bowel habits were observed between groups.

Trans-rectal Ultrasound-Guided Autologous Blood Injection in the Interprostatorectal Space Prior to Percutaneous MRI-Guided Cryoablation of the Prostate

OBJECTIVE

To report a novel technique of ultrasound-guided injection of autologous blood in the interprostatorectal space, in an attempt to facilitate ablative prostatic procedures by widening durably the space between the rectum and the prostate.

MATERIALS AND METHODS

Between April and November 2016, four consecutive patients underwent the haemoprotection injection technique. For each patient, we recorded the time to perform the technique, the amount of injected blood, the achieved distances between the rectum and the prostate post-injection at fixed defined points (apex, middle, and base of prostate at the midline, left, and right sides of the gland), the extension of the ice ball outside the prostate capsule at those fixed points, and whether any residual blood was present on 1-month follow-up MRI.

RESULTS

Mean time to perform haemoprotection injection was 54 min, with an average blood volume of 103 cc. Mean distance achieved at the apex, middle, and base of the prostate, respectively, was 12, 13, and 16 mm in the midline; 8, 10, and 13 mm on the left side; and 9, 10, and 13 mm on the right side. The mean extension distance of the ice ball beyond the capsule was 4, 6, and 6 mm in the midline; 4, 5, and 6 mm on the left side; and 1, 3, and 3 mm on the right side. No residual blood was present on 1-month follow-up MRI in all patients. No rectal fistula occurred.

CONCLUSION

Haemoprotection may create a safe and effective virtual space between the prostate and rectum.

Percutaneous image-guided cryoablation: current applications and results in the oncologic field

Percutaneous imaging-guided cryoablation (PICA) is a recently developed technique, which applies extreme hypothermia to destroy tumours under close imaging surveillance. It is minimally invasive, safe, repeatable, and does not interrupt or compromise other oncologic therapies. It presents several advantages over more established heat-based thermal ablation techniques (e.g. radiofrequency ablation; RFA) including intrinsic analgesic properties, superior monitoring capability on multi-modal imaging, ability to treat larger tumours, and preservation of tissue collagenous architecture. There has been a recent large increase in reports evaluating the utility of PICA in a wide range of patients and tumours, but systematic analysis of the literature is challenging due to the rapid pace of change and predominance of extensively heterogeneous level III studies. The precise onco-therapeutic role of PICA has not been established. This narrative review outlines the available evidence for PICA in a range of tumours. Current indications include curative therapy of small T1a renal tumours; curative/palliative therapy of small primary/secondary lung tumours where RFA is unsuitable; palliation of painful bone metastases; and urologic treatment of organ-confined prostate cancer. There is growing evidence to support its use for small hepatic tumours, and encouraging results have been obtained for breast tumours, extra-abdominal desmoid tumours, and management of higher-stage tumours and oligometastatic disease. However, the overall evidence base is weak, effectively restricting PICA to cases where standard therapy and RFA are unsuitable. As the technique and evidence continue to mature, the benefits of this emerging technique will hopefully become more widely available to cancer patients in the future.