Cryosurgical ablation of the prostate

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.

Issues Critical to the Successful Application of Cryosurgical Ablation of the Prostate

The techniques of present-day cryosurgery performed with multiprobe freezing apparatus and advanced imaging techniques yield predictable and encouraging results in the treatment of prostatic and renal cancers. Nevertheless, and not unique to cryosurgical treatment, the rates of persistent disease demonstrate the need for improvement in technique and emphasize the need for proper management of the therapeutic margin. The causes of persistent disease often relate to a range of factors including selection of patients, understanding of the extent of the tumor, limitations of the imaging techniques, and failure to freeze the tumor periphery in an efficacious manner. Of these diverse factors, the one most readily managed, but subject to therapeutic error, is the technique of freezing the tumor and appropriate margin to a lethal temperature [Baust, J. G., Gage, A. A. The Molecular Basis of Cryosurgery. BJU Int 95, 1187–1191 (2005)]. This article describes the recent experiments that examine the molecular basis of cryosurgery, clarifies the actions of the components of the freeze-thaw cycle, and defines the resultant effect on the cryogenic lesion from a clinical perspective. Further, this review addresses the important issue of management of the margin of the tumor through adjunctive therapy. Accordingly, a goal of this review is to identify the technical and future adjunctive therapeutic practices that should improve the efficacy of cryoablative techniques for the treatment of malignant lesions.

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

Cryosurgery (CS) has been used on patients with clinically localized PCa for more than 10 years. However, clinical studies evaluating its effectiveness and safety have reported conflicting results. This systematic assessment was performed to obtain comprehensive evidence regarding the potential benefits and safety of CS compared with those of radiotherapy (RT) and radical prostatectomy (RP), respectively. All controlled trials comparing CS with RT or RP and single-arm studies reporting results of CS therapy were identified through comprehensive searches of PubMed, the Cochrane Library and Embase. Ten publications from seven trials, with totally 1252 patients, were included in the meta-analysis, which revealed no significant differences in comparisons of CS vs RT and CS vs RP for overall survival and disease specific survival. However, a significantly lower disease-free survival could be observed for CS than RP. Moreover, a systematic review of literature focusing on comparative data of databases and materials of single-arm trials revealed satisfactory survival results in both primary and salvage CS. Our results showed that cryosurgery would be a relatively effective method for clinically localized prostate cancer with survival results comparable to radiotherapy and radical prostatectomy. However, the large percentage of complications caused by cryosurgery should be carefully monitored.

Gleason score and tumor laterality in radical prostatectomy and transrectal ultrasound-guided biopsy of the prostate: a comparative study

We aimed to compare Gleason score and tumor laterality between transrectal ultrasound-guided biopsy of the prostate (TRUSBX) and radical prostatectomy (RP). Some factors that could cause a discrepancy in results between these two procedures were also evaluated. Among the 318 cases reviewed, 191 cases were selected for inclusion in this comparative study. We divided the patients into two groups using the Gleason score: an intermediate/high-grade group (≥7) and a low-grade group (<6). Exploratory analyses were conducted for comparisons between groups. We also performed comparisons between TRUSBX and RP for tumor laterality. TRUSBX overestimated 6% and underestimated 24% cases in comparison with RP for Gleason score, and overestimated 2.6% and underestimated 46% cases compared with RP for tumor laterality. Biopsy specimens were slightly smaller in TRUSBX cases with underestimated tumor laterality (P < 0.05), and no relationship between the biopsy specimen size and underestimated Gleason score in TRUSBX was found. Prostatic volume showed no statistical correlation with the likelihood of under or overestimation (P > 0.05). Thus, our study showed that TRUSBX has a high likelihood of underestimating both the Gleason score and tumor laterality in prostate cancer (PCa). The size of the fragment appears to be an important factor influencing the likelihood of laterality underestimation and Gleason score overestimation via TRUSBX. Due to the high likelihood of underestimation of the Gleason score and tumor laterality by 12-core prostate biopsy, we conclude that this type of biopsy should not be used alone to guide therapy in PCa.

The feasibility and safety of repeat cryosurgical ablation of localized prostate cancer

BACKGROUND

The aim of the study was to assess the morbidity and efficacy of repeat cryoablation (CA) in the treatment of localized prostate cancer.

METHODS

Twenty-seven patients with median age of 71 years (range 48-80) who underwent repeat CA between April 2003 and April 2011 at a single institution were included. The median initial prostate-specific antigens (PSA) and Gleason values were 6.2 ng/ml (range 4-23.6) and 7 (range 6-9), respectively. Twenty-four patients underwent two CA treatments, and three patients underwent three CA treatments. Pre- and perioperative parameters and oncological and functional outcomes were evaluated.

RESULTS

No intraoperative complications occurred. After the first CA, PSA was undetectable in 10 patients, and the median nadir PSA value was 0.65 ng/ml (range 0.1-4.9). After the second CA, 4 patients had undetectable PSA, and the median nadir PSA value was 1.25 ng/ml (range 0.2-7.9). For patients who underwent a third CA treatment, no patients had undetectable PSA, and the subsequent median nadir PSA value was 1.6 ng/ml (range 0.4-4.5). Two patients had incontinence (1 pad per day) following repeat CA. One patient had urinary retention after the third CA treatment, and one had urethral stricture. The mean hospitalization and follow-up periods were 1 day (range 0-2) and 51.5 months (range 11-96), respectively.

CONCLUSIONS

Repeat CA successfully reduced PSA levels, and complications were modest. We conclude that repeat CA is a feasible, safe, and effective treatment option for localized prostate cancer.

A pretreatment nomogram for prediction of biochemical failure after primary cryoablation of the prostate

BACKGROUND

To create a predictive nomogram for biochemical failure following primary whole-gland cryoablation of the prostate for localized prostate cancer (LPCa).

METHODS

We retrospectively analyzed 2,242 patients from the Cryo On-Line Database (COLD) who were treatment naive and had undergone primary whole gland cryoablation of the prostate for biopsy-confirmed LPCa. Kaplan-Meier (KM) curves estimating 5 year biochemical progression-free survival (bPFS) were generated. Multivariable Cox proportional hazards analysis (CoxPH) was performed in order to construct the nomogram. The nomogram was internally validated using the bootstrap technique.

RESULTS

Overall, the KM estimated 5 year bPFS was 72.8%. Stratified by D'Amico risk, The KM estimated 5 year bPFS was 82.6%, 71.1%, and 57.8% for low-, intermediate-, and high-risk groups, respectively. Statistically significant predictors of biochemical outcomes from CoxPH analysis were pre-treatment prostate specific antigen (PTPSA) (P < 0.001), total prostate volume (P = 0.004), clinical stage (P = 0.034), and Gleason score (0.004). A nomogram for predicted 5 year biochemical progression free probability was constructed with a concordance index of 0.652. An online risk calculator was also generated.

CONCLUSIONS

To the best of our knowledge, this is the first predictive nomogram for biochemical outcomes after primary whole gland cryoablation of the prostate using socio-demographic, pretreatment, clinical, and prostate biopsy data. Our nomogram and online risk calculator can guide both patients and urologists for shared decision making regarding definitive treatment options.

Predictors of prostate-specific antigen biochemical recurrence in patients undergoing primary whole-gland prostate cryoablation

PURPOSE

Cryoablation has been proven as a less invasive, safe, and effective treatment for localized prostate cancer. We attempted to identify the predictors of biochemical recurrence after prostate cryoablation for localized prostate cancer in this study.

METHODS

We reviewed 114 patients who underwent primary whole-gland prostate cryoablation for localized prostate cancer from October 2008 to March 2013. The perioperative parameters included age >70 years, initial prostate-specific antigen (PSA), preoperative prostate volume, Gleason score, T stage, D'Amico risk group, postoperative PSA nadir, time to PSA nadir, and PSA biochemical recurrence, defined by Phoenix definition (nadir plus 2 ng/mL). Receiver operating characteristic (ROC) analysis was used for the best cutoff value of PSA nadir for PSA biochemical recurrence. The parameters were analyzed in binary logistic regression and Kaplan-Meier analysis for PSA biochemical recurrence.

RESULTS

A total of 31.6 % (N = 36) patients had PSA biochemical recurrence during the median follow-up of 34.87 ± 16.49 months. ROC analysis revealed that the best cutoff value for biochemical recurrence prediction was when the PSA nadir = 0.3 ng/mL. On multivariate analysis and Kaplan-Meier analysis, the D'Amico high-risk group [hazard ratio (HR) 6.552; p = 0.014], PSA nadir >0.3 ng/mL (HR 34.062; p < 0.001), and time to PSA nadir <3 months (HR 4.144; p = 0.021) were statistically significant for PSA biochemical recurrence.

CONCLUSIONS

The D'Amico high-risk group, postoperative PSA nadir >0.3 ng/mL, and time to PSA nadir <3 months predict biochemical recurrence in primary whole-gland prostate cryoablation.

Cryotherapy in prostate cancer

Review objectives:

Cryotherapy use has increased due to technological advances. A review of the literature was performed to evaluate the efficacy and outcomes of whole gland, salvage and targeted focal cryotherapy in the management of prostate cancer.

Review findings:

Cryotherapy use has increased significantly over the last 10 years with a trend towards focal ablation. Whole gland cryotherapy, salvage cryotherapy and focal cryotherapy biochemical recurrence rates appear to be comparable to other treatment modalities for low risk disease, however biochemical failure remains difficult to compare across studies due to a lack of consensus regarding appropriate end points for evaluation of cryotherapy. Short-term focal cryotherapy outcomes are encouraging. Side effect profiles for cryotherapy have significantly improved with fourth generation systems while salvage cryotherapy continues to carry a slightly higher risk of incontinence than primary whole gland cryotherapy. The incidence of erectile dysfunction after focal cryotherapy is dramatically lower than that for whole gland ablation.

Conclusions:

Cryotherapy continues to have an active role in the primary and salvage treatment of prostate cancer. Targeted focal cryotherapy is a promising treatment with minimal morbidity. Further long-term data is needed to support targeted therapy in addition to direct comparison with other treatment modalities.

Surgical management of prostate cancer

Surgery remains a mainstay in the management of localized prostate cancer. This article addresses surgical aspects germane to the management of men with prostate cancer, including patient selection for surgery, nerve-sparing approaches, minimization of positive surgical margins, and indications for pelvic lymph node dissection. Outcomes for men with high-risk prostate cancer following surgery are reviewed, and the present role of neoadjuvant therapy before radical prostatectomy is discussed. In addition, there is a review of the published literature on surgical ablative therapies for prostate cancer.

Cryotherapy for primary treatment of prostate cancer: intermediate term results of a prospective study from a single institution

Purpose. Published data about cryotherapy for prostate cancer (PC) treatment are based on case series with a lack of clinical trials and the inexistence of a validated definition of biochemical failure. A prospective study with standardized followup protocol was conducted in our institution. Material and Methods. Prospective study of a series of cases including 108 patients diagnosed with localized PC at clinical stage T1c-T2c treated by primary cryoablation and median followup of 61 months. Criteria of biochemical recurrence were unified according to the American Society for Therapeutic Radiology and Oncology (ASTRO). End points were biochemical progression-free survival (BPFS), cancer-specific survival, and overall survival. Rate of complications was reported. Results. The BPFS for low-, medium-, and high-risk patients was 96.4%, 91.2%, and 62.2%, respectively. Cancer-specific survival was 98.1%. Overall survival reached 94.4%. Complications included incontinence in 5.6%, urinary tract obstruction in 1.9%, urethral sloughing in 5.6%, haematuria in 1.9%, perineal pain in 11.1%, and prostatorectal fistula in 0.9%. Erectile disfunction was found in 98.1%. Conclusions. Cryotherapy is an effective and minimally invasive treatment for primary PC in well-selected cases, with low surgical risk and good results in terms of BPFS, cancer-specific survival, and overall survival.

Primary cryosurgery for clinically localized prostate cancer--do perioperative tumor characteristics correlate with post-treatment biopsy results?

OBJECTIVE

To investigate the rate and predictive factors of positive post-treatment biopsy in men treated with primary cryosurgery for localized prostate cancer.

METHODS

A retrospective review was performed of all patients treated with primary cryosurgery at a single institution between 1999 and 2012. Perioperative prostate-specific antigen (PSA) levels, Gleason score, and number of positive preoperative biopsy cores were obtained and correlated with postoperative biopsy results. Patients were stratified according to the risk classification system of D'Amico to low-, intermediate-, or high-risk groups.

RESULTS

Sixty-five men were treated with primary cryosurgery, and 57 of 65 (88%) of them underwent postoperative biopsy on average 9 months after the treatment. Eleven of 57 patients (19%) were found to have persistent tumor on post-treatment biopsy. Men who had positive biopsy had significantly higher perioperative PSA levels than men who had negative biopsy (preoperative PSA 12.5 vs 6.2, P = .002; post-operative PSA nadir 4.3 vs 0.71, P = .005); however, no independent predictor was found on a multivariate analysis. Gleason score and number of positive preoperative biopsy cores did not predict tumor persistence. Positive biopsy results were found more often in the intermediate- and high-risk patients, although this was not statistically significant (low risk 9%, intermediate risk 20%, and high risk 27%).

CONCLUSION

Perioperative PSA levels, Gleason score, or number of positive pretreatment biopsy cores do not predict failure after primary cryosurgery for clinically localized prostate cancer. Our findings suggest that physicians, who offer primary cryosurgery to patients with localized prostate cancer, should consider offering post-treatment biopsy to patients to assure adequate cancer control.

Treatment profile and complications associated with cryotherapy for localized prostate cancer: a population-based study

The aim of this study was to assess the treatment patterns and 3-12-month complication rates associated with receiving prostate cryotherapy in a population-based study. Men >65 years diagnosed with incident localized prostate cancer in Surveillance Epidemiology End Results (SEER)-Medicare-linked database from 2004 to 2005 were identified. A total of 21,344 men were included in the study, of which 380 were treated initially with cryotherapy. Recipients of cryotherapy versus aggressive forms of prostate therapy (ie, radical prostatectomy or radiation therapy) were more likely to be older, have one co-morbidity, low income, live in the South and be diagnosed with indolent cancer. Complication rates increased from 3 to 12 months following cryotherapy. By the twelfth month, the rates for urinary incontinence, lower urinary tract obstruction, erectile dysfunction and bowel bleeding reached 9.8, 28.7, 20.1 and 3.3%, respectively. Diagnoses of hydronephrosis, urinary fistula or bowel fistula were not evident. The rates of corrective invasive procedures for lower urinary tract obstruction and erectile dysfunction were both <2.9% by the twelfth month. Overall, complications post-cryotherapy were modest; however, diagnoses for lower urinary tract obstruction and erectile dysfunction were common.

Primary full-gland prostate cryoablation in older men (> age of 75 years): results from 860 patients tracked with the COLD Registry

Study Type - Therapy (outcomes research).

LEVEL OF EVIDENCE

2c. What's known on the subject? and What does the study add? Most elderly patient with prostate cancer undergo radiation therapy, but cryoablation has gained popularity. This study demonstrates the safety and efficiency of this new approach.

OBJECTIVE

• To report on the largest data set regarding outcomes for whole gland prostate cryoablation as a primary treatment of prostate cancer in older men, which we empirically defined as age >75 years.

MATERIALS AND METHODS

• The COLD (Cryo On-Line Data) Registry consists of case report forms with pre- and post-treatment information obtained from patients undergoing prostate cryoablation. • A total of 860 patients were stratified into low-, intermediate- and high-risk groups (D'Amico 2003 risk definitions). • Biochemical disease-free survival (bDFS) was defined according to the traditional American Society for Therapeutic Radiology and Oncology definition (3 increases) and the newer (Phoenix) definition (nadir +2). • Biopsy was performed at physician discretion but most commonly for cause if a patient had an increasing or suspicious prostate-specific antigen level (PSA).

RESULTS

• The median age was 79 years (76-91) and the median follow-up was 16 months (4-60). • The 5-year [95% confidence interval (CI)] bDFS for the entire population using ASTRO and Phoenix definitions was 79% (4%) and 62.6% (8.3%), respectively. • Stratified by risk group, 5-year bDFS (ASTRO) was 82.4% (7.9%), 78.3% (5.8%) and 77.6% (7.7%) for low, moderate and high risk, respectively. • Using the Phoenix definition, 5-year bDFS was 74.9%± 15.3%, 61.4%± 13.2% and 58.0%± 11.9% for low-, moderate- and high-risk groups, respectively. • Incontinence was reported in eight patients (0.9%).

CONCLUSION

• Whole gland cryoablation in older men maintains oncological efficacy similar to that of younger men without increased morbidity.

Minimally invasive ablative therapies for definitive treatment of localized prostate cancer in the primary setting

Traditionally, the patient with a new diagnosis of localized prostate cancer faces either radical therapy, in the form of surgery or radiation, or active surveillance. A growing subset of these men may not be willing to accept the psychological burden of active surveillance nor the side effects of extirpative or radiation therapy. Local ablative therapies including cryotherapy, high-intensity focused ultrasound, and vascular-targeted photodynamic therapy have emerged as a means for minimally invasive definitive treatment. These treatments are well tolerated with decreased morbidity in association with improvements in technology; however, long-term oncologic efficacy remains to be determined.

Long-term cancer-specific and overall survival for men followed more than 10 years after primary and salvage cryoablation of the prostate

INTRODUCTION

Ten-year disease-specific survival for clinically localized prostate cancer after radiation is 93%, 88%, and 80% for low-, medium-, and high-risk groups, respectively. The objective of this study was to report long-term cancer survival outcomes for patients who had undergone prostate cryotherapy at our institution more than 10 years ago. To date, this is the longest reported follow-up after cryotherapy.

MATERIALS AND METHODS

A retrospective patient chart review, conducted of an Institutional Review Board (IRB)- approved cryotherapy database, identified 76 men who had undergone prostate cryotherapy before January 1999. Pre-, intra-, and posttreatment data were collected. Primary study endpoints were overall mortality and prostate-cancer-specific death. Secondary endpoints were disease recurrence and clinical progression.

RESULTS

Mean patient age was 69.2 (47.4-86.3) years; median preoperative prostate-specific antigen was 5.3 (0.2-208.0); mean Gleason score was 7. Forty of 76 (52.6%) were confirmed D'Amico high risk. Median follow-up was 10.1 (0.2-14.9) years; 25 patients underwent primary treatment; 51 postradiation. After 10 years of follow-up, 43 of 76 men (56.6%) were still alive; 33 men (43.4%) had died-10 (13.2%) from prostate cancer, 18 (22.4%) from noncancerous causes, and 5 (6.6%) unknown.

CONCLUSIONS

The long-term results of prostate cryotherapy in our series indicate an 87% overall 10-year prostate-cancer-specific survival, despite early cryotherapy technology and the majority of patients being D'Amico high risk.

The biochemical efficacy of primary cryoablation combined with prolonged total androgen suppression compared with radiotherapy on high-risk prostate cancer: a 3-year pilot study

To gain beneficial effects in the management of high-risk prostate cancer, an integrated approach that combines local therapy and androgen deprivation therapy (ADT) was used. We compared biochemical responses between primary cryosurgical ablation of the prostate (CSAP) combined with prolonged ADT and radiation combined with ADT, which is the established modality in high-risk disease. A total of 33 high-risk patients received CSAP combined with ADT for 3 months before and up to 24 months after treatment. This patient group was matched with another 33 patients who had undergone three-dimensional conformal radiation therapy (3D-CRT) with the same protocol for ADT. Biochemical recurrence (BCR) was assessed by the American Society for Therapeutic Radiation Oncology (ASTRO) definition, the Phoenix definition and a prostate-specific antigen (PSA) cutoff of 0.5 ng mL(-1). Median follow-up was 61.0 ± 11.9 months for the CSAP + ADT group and 86.0 ± 15.8 months for the 3D-CRT + ADT group. In the CSAP group, major complications including rectourethral fistula and incontinence were not noted. In the CSAP + ADT group, 57.0% had BCR using the ASTRO definition, 21.2% using the Phoenix definition and 54.5% using a PSA cutoff of 0.5 ng mL(-1). In the 3D-CRT + ADT group, 54.5%, 21.2% and 54.5% had BCR using the ASTRO, Phoenix and PSA definition, respectively. In the CSAP + ADT group, the BCR-free survival (BRFS) was 54 ± 10 months using the ASTRO definition, 65 ± 5 months using the Phoenix definition and 51 ± 4 months using a PSA cutoff of 0.5 ng mL(-1). In the 3D-CRT + ADT group, the BRFS was 68 ± 12, 93 ± 19 and 70 ± 18 months using the ASTRO, Phoenix and PSA definition, respectively. By the log-rank test, the BRFS values for each group were not statistically different. This intermediate-term result indicated that primary CSAP combined with prolonged ADT offers a parallel biochemical response compared with radiotherapy in high-risk prostate cancer.

HIFU and cryoablation – non or minimal touch techniques for the treatment of prostate cancer. Is there a role for contrast enhanced ultrasound?

The incidence of prostate cancer is increasing, and therefore also the need for optimal treatment. Because of the appearance of many different disease stages different treatment modalities are desirable for the treatment of localized prostate cancer. The established therapies, radical prostatectomy and radiation therapy, are associated with a lot of risks, complications and co-morbidity, and not all patients are eligible for these treatments. That is why the need for reliable minimally invasive alternatives has developed. For this paper a literature search was conducted on published studies and review articles to determine the role of HIFU (high intensity focused ultrasound) and cryoablation as minimally invasive treatment modalities for localized prostate cancer. Both therapies are being used as a primary or secondary (salvage) treatment, but can they replace surgery or radiation? And is there a role for contrast enhanced ultrasound (CEUS) of the prostate to improve diagnostics, treatment outcomes and follow-up? To date the outcomes of both therapies are promising but no prospective and comparative randomized studies with a long term follow-up were available for analysis. From this review we can conclude that until those studies are available, HIFU and cryoablation are good alternatives for patients not eligible for prostatectomy or radiation. They should not be used as a first treatment option as long as diagnostics and follow-up have not improved.

Primary cryoablation for Gleason 8, 9, or 10 localized prostate cancer: Biochemical and local control outcomes from the Cryo OnLine database registry

INTRODUCTION AND OBJECTIVE

The increased use of cryoablation as an initial treatment for localized high-grade prostate cancer has been due to many factors including reports that cell kill from exposure to cryogenic temperatures is independent of cellular dedifferentiation and Gleason score. The objective of this study is to report the outcomes of primary cryoablation when used to treat Gleason 8, 9, or 10 localized prostate cancer at a large number of centers.

MATERIALS AND METHODS

Data from 1608 patients who underwent primary cryoablation at 27 centers were collected using the Cryo OnLine Database (COLD) registry. This analysis considers only the 77 patients who had a Gleason score of at least 8 and a minimum of 24 months of follow-up. Biochemical failure was defined according to both the original ASTRO definition (three rises) and the 2006 updated ASTRO (Phoenix) definition of nadir + 2. Biopsy was performed at the physician's discretion, but most commonly if a patient had a rising or suspicious prostate specific antigen (PSA).

RESULTS

The average age at treatment was 69.6 +/- 8.2 years. Pretreatment PSA was 16.2 +/- 17.9 ng/ml and the average Gleason was 8.5 +/- 0.6. Patients were followed for 39.0 +/- 18.8 months (range: 24-120 months) and 5-year follow-up was available for 12 patients. Eight-seven percent of the patients achieved a PSA nadir < 0.4 ng/ml. Five-year actuarial biochemical survivals was 64.4 +/- 6.0% and 44.6 +/- 8.0% for the ASTRO and Phoenix definitions, respectively. A total of 47 underwent posttreatment biopsy. Of these, 12 showed evidence of disease resulting in a positive biopsy rate for those who underwent biopsy of 25.5%. This yields a positive biopsy rate of the entire population of 15.6% (12/77).

CONCLUSIONS

Cryoablation, as a primary treatment for high-grade Gleason prostate cancer practiced over a wide spectrum of users provides definable biochemical and local control for a hard to manage patient population with aggressive disease.

The pathophysiology of thermoablation: optimizing cryoablation

PURPOSE OF REVIEW

To describe the response of prostate cancer to thermal therapies with an emphasis on cryoablative techniques.

RECENT FINDINGS

Long-term follow-up studies demonstrate clearly the effectiveness of the use of modern cryoablative techniques in the management of prostate cancer. Recently published American Urology Association Best Practice Guidelines identify prostate cryoablation as both primary and salvage therapies. Recent findings demonstrate the effectiveness of -40 degrees C exposure as lethal to prostate cancer genotypes following a double freeze-thaw encounter. In addition, the use of adjunctive agents to sensitize the cancer to freezing is reported.

SUMMARY

Thermal therapeutic options, especially cryoablation, are of growing interest for the treatment of prostatic and renal cancers. The methods of application of cryoablative therapy and the mechanisms of cell death that are attendant to the freezing-thaw encounter are clearly understood. Research focused on the development of freeze sensitizing agents that work adjunctively is of central interest in furthering the efficacy of this therapy.

Focal therapy for prostate cancer: revolution or evolution?

The face of prostate cancer has been dramatically changed since the late 1980s when PSA was introduced as a clinical screening tool. More men are diagnosed with small foci of cancers instead of the advanced disease evident prior to PSA screening. Treatment options for these smaller tumors consist of expectant management, radiation therapy (brachytherapy and external beam radiotherapy) and surgery (cryosurgical ablation and radical prostatectomy). In the highly select patient, cancer specific survival employing any of these treatment options is excellent, however morbidity from these interventions are significant. Thus, the idea of treating only the cancer within the prostate and sparing the non-cancerous tissue in the prostate is quite appealing, yet controversial. Moving forward if we are to embrace the focal treatment of prostate cancer we must: be able to accurately identify index lesions within the prostate, image cancers within the prostate and methodically study the litany of focal therapeutic options available.

Diffusion-weighted imaging of the prostate and rectal wall: comparison of biexponential and monoexponential modelled diffusion and associated perfusion coefficients

This study compares parameters from monoexponential and biexponential modelling of diffusion-weighted imaging of normal and malignant prostate tissue and normal rectal wall tissues. Fifty men with Stage Ic prostate cancer were studied using endorectal T(2)-weighted imaging and diffusion-weighted imaging with 11 diffusion-sensitive values (b-values = 0, 1, 2, 4, 10, 20, 50, 100, 200, 400, 800 s/mm(2)). Regions of interest were drawn within non-malignant central gland and peripheral zone, malignant prostate tissue and normal rectal wall tissue. Both a monoexponential and biexponential model was fitted over various b-value ranges, giving an apparent diffusion coefficient (ADC) from the monoexponential model and a diffusion coefficient, perfusion coefficient and perfusion fraction from the biexponential model. In all tissues, over the full range of b-values, the ADC from the monoexponential model was significantly higher than the corresponding diffusion coefficient from the biexponential model. As the minimum b-value increased, the ADC decreased and was equal to the diffusion coefficient for some b-value ranges. The biexponential model best described the data when low b-values were included, suggesting that there is a fast perfusion component. Neither model could distinguish between benign prostate tissues on the basis of diffusion coefficients, but the rectal wall tissue and malignant prostate tissue had significantly lower diffusion coefficients than normal prostate tissues. Perfusion coefficients and fractions were highly variable within the population, so their clinical utility may be limited, but removal of this variable perfusion component from reported diffusion coefficients is important when attributing clinical differences to diffusion within tissues.

New treatments for localized prostate cancer

Interest in focal therapy for prostate cancer has recently been renewed owing to downward stage migration, improved biopsy and imaging techniques, and the prevalence of either unifocal cancer or a dominant cancer with secondary tumors of minimal malignant potential. Several techniques have potential for focal ablation of prostate cancer. Cryotherapy has been used for some time as primary therapy for complete ablation of the prostate or local recurrence after radiotherapy. Enthusiasm for cryotherapy as the primary therapy has been tempered by the uncertainty about complete ablation of the cancer, the frequent persistence of measurable prostate-specific antigen levels after the procedure, and a high rate of erectile dysfunction. Studies have reported "focal ablation" of prostate cancer with cryotherapy, targeting 1 side of the gland to eliminate a cancer confined to that side with less risk of urinary or sexual complications. Whether cryotherapy has sufficient power to eradicate focal cancer and can be targeted with sufficient accuracy to avoid damage to surrounding structures remains to be demonstrated in prospective clinical trials. High-intensity focused ultrasound (HIFU) has been used widely in Europe for complete ablation of the prostate, especially in elderly men who are unwilling or unable to undergo radical therapy. For low- or intermediate-risk cancer, the short- and intermediate-term oncologic results have been acceptable but need confirmation in prospective multicenter trials presently underway. Whole gland therapy with transrectal ultrasound guidance has been associated with a high risk of acute urinary symptoms, often requiring transurethral resection before or after HIFU. Adverse effects on erectile function seem likely after a therapy that depends on heat to eradicate the cancer, but erectile function after HIFU has not been adequately documented with patient-reported questionnaires. HIFU holds promise for focal ablation of prostate cancer. As with cryotherapy, focal HIFU should reduce the adverse sexual, urinary, and bowel effects of whole gland ablation. New techniques are being developed to allow HIFU treatment under real-time guidance using magnetic resonance imaging, which could improve the precision and reduce the adverse effects further. Another promising technique, currently in clinical trials, is vascular-targeted photodynamic therapy, which has been used for whole gland ablation of locally recurrent cancer after radiotherapy and, more recently, for focal ablation of previously untreated cancer. In combination with a new, systemically administered photodynamic agent, laser light is delivered through fibers introduced into the prostate under ultrasound guidance. This technique does not heat the prostate but destroys the endothelial cells and cancer by activating the photodynamic agent. Damage to surrounding structures appears to be limited and can be controlled by the duration and intensity of the light. We have reviewed the principles of focal therapy and these new therapeutic modalities.

MR imaging-guided percutaneous cryoablation of the prostate in an animal model: in vivo imaging of cryoablation-induced tissue necrosis with immediate histopathologic correlation

PURPOSE

To evaluate the feasibility of magnetic resonance (MR) imaging-guided percutaneous cryoablation of normal canine prostates and to identify MR imaging features that accurately predict the area of tissue damage at a microscopic level.

MATERIALS AND METHODS

Six adult male mixed-breed dogs were anesthetized, intubated, and placed in a 0.5-T open MR imaging system. A receive-only endorectal coil was placed, and prostate location and depth were determined on T1-weighted fast spin-echo (FSE) MR imaging. After placement of cryoprobes and temperature sensors, three freezing protocols were used to ablate prostate tissue. Ice ball formation was monitored with T1-weighted FSE imaging. Tissue necrosis area was assessed with contrast-enhanced weighted MR imaging and compared with histopathologic findings.

RESULTS

A total of 12 cryolesions (mean size, 1.2 cm) were bilaterally created in six prostates. Ice ball formation was oval and signal-free on T1-weighted FSE sequences in all cases. Postprocedural contrast-enhanced MR imaging typically showed a nonenhancing area of low signal intensity centrally located within the frozen area, surrounded by a bright enhancing rim in all cases. On histopathologic examination, two distinct zones were identified within cryolesions. Centrally, a necrotic zone with complete cellular destruction and hemorrhage was found. Between this necrotic zone and normal glandular tissue, a zone of fragmented and intact glands, interstitial edema, and rare acute inflammatory cells was seen. Correlation between nonenhancement on contrast-enhanced weighted MR images and tissue necrosis on pathologic examination was consistent within all six dogs.

CONCLUSIONS

MR imaging-guided cryoablation of the prostate is technically feasible. The nonenhancing area on postablation contrast-enhanced weighted MR imaging accurately predicts the area of cryoablation-induced tissue necrosis on pathologic analysis.

Giant organ confined prostatic adenocarcinoma: a case report

Introduction

Giant prostatic adenocarcinoma represents a rare and challenging treatment dilemma.

Case presentation

We describe a case of an otherwise healthy 71-year-old African male who presented with a PSA of 5800 ng/ml and a prostate volume of over 1000cc. Unique aspects of this case include the size of the prostate, the apparent absence of distant metastases, and the safe usage of transabdominal biopsy of this mass.

Conclusion

We present this case report and review of literature to generate further discussion amongst readers as to management options for this difficult case.

The current use and future trends of focal surgical therapy in the management of localized prostate cancer

The current treatment algorithms for management of localized prostate cancer are mainly extirpative in nature. Treatment varies from expectant management to radical prostatectomy or radiation therapy. However, the ever-increasing emphasis on achieving the best survival benefit while better preserving quality of life, coupled with the introduction of new, safer, and efficacious minimally invasive ablative technologies, has led to the increased popularity of minimally invasive treatment (MIT). MIT refers to the use of a wide range of techniques for local target ablation of the prostate gland with minimal damage to the surrounding tissue. Currently these include cryotherapy and high-intensity focused ultrasound. However, other experimental technologies such as photodynamic therapy, interstitial prostate brachytherapy, and microwave and radiofrequency interstitial tumor ablation are also currently under investigation in early clinical trials. To date, the overall interim results for these relatively new modalities of treatment appear comparable to those for surgical and radiation therapies. However, randomized, controlled studies are needed to support use of these modalities as an alternative to surgery and radiation. In this review, we will address the current rationale for and knowledge of MIT with regard to its safety and efficacy in the treatment of localized prostate cancer. In addition, we will discuss future promising tools in MIT such as photodynamic therapy and the target focal therapy approach as a new trend for the treatment of organ-confined low-volume disease.

Review of primary and salvage cryoablation for prostate cancer

BACKGROUND

Cryosurgery has gained popularity as a minimally invasive treatment option for primary and recurrent prostate cancer. Herein we present a review and summary reports on primary cryoablation for prostate cancer and salvage cryoablation following radiation failure.

METHODS

We reviewed the current published literature in the English language on these topics, along with some historic articles dating back to the 1960s for background and development of the procedure. The material is supplemented by some commentary based on our own 13-year experience with cryoablation for prostate cancer. The review is divided into two sections: primary and salvage cryoablation.

RESULTS

For primary cryoablation, success rates are proportional to the risk categories of the primary cancers. A pretreatment prostate-specific antigen (PSA) <or= 10 ng/mL and an undetectable PSA nadir following cryoablation are associated with a more favorable long-term outcome. Safety profile and quality of life are acceptable in carefully selected patients. Similarly, for salvage cryoablation following radiation failure, patient selection is of paramount importance. The most consistently identified predictive factors for poor cryoablation outcomes were pre-cryoablation PSA > 10 ng/mL and post-cryoablation nadir PSA > 1 ng/mL for salvage procedures. Side effects are more prevalent and serious than with primary cryoablation but for carefully selected patients, the long-term results are favorable.

CONCLUSIONS

Patient selection is the key to success with cryoablation, in both the primary and salvage setting. The modality can offer long-term cancer control in carefully selected patient with properly executed techniques.

[Cryosurgery in the management of prostate cancer]

This article reviews the current status of the prostatic cryosurgery in the management of patients with prostate cancer. Recent advances in cryoablative technology have allowed to treat these patients successfully with decreased morbidity. Using transrectal high-resolution ultrasound imaging, prostate cryotherapy is delivered with multiple ultrathin (17-gauge) cryo-needles, via percutaneous transperineal approach. The extent of freezing can be precisely controlled and monitored with thermic devices, tissue destruction is monitored with real-time visualization of the prostate and surrounding structures, and urethral warming is used to avoid urethral sloughing. However, the results with the second and third-generation cryosurgical equipment will have to be confirmed by means of prospective and randomized trials, because up to now we only have data based on retrospective analyses, which are very heterogeneous. The ability of prostate-specific antigen (PSA) to predict long-term outcome after cryotherapy for localized prostate cancer is not well known because experience with this treatment modality is still limited; however, it seems that a PSA value of 0.5 ng/ml or less after 6 months or longer after cryotherapy would be associated with a high probability (greater than 95%) of negative post-treatment biopsy. Cryosurgery could also be an option of treatment for men with recurrent local disease who have undergone radiotherapy or radical prostatectomy. We have to keep in mind possible complications (incontinence, impotency, urethrorectal fistula or bladder outlet obstruction. The favorable side effect profile and preliminary oncologic and funtional results could suggest that cryosurgery will have a role in the minimally invasive management of selected patients with prostate cancer.

Focal cryosurgery: encouraging health outcomes for unifocal prostate cancer

OBJECTIVES

Owing to the ability to better detect small-volume tumors, we have seen an increasing population of men with low-risk unifocal prostate cancer. We report our safety and efficacy experience of focal cryoablation of the prostate to maintain potency and preserve genitourinary function in men with localized, unifocal disease.

METHODS

From June 2002 to December 2005, 25 patients with primary unifocal prostate cancer were treated with focal cryoablation of the prostate. The patients were followed up with physical examinations, morbidity questionnaires, and prostate-specific antigen (PSA) determinations every 3 months for the first year and every 6 to 12 months thereafter. Patients with a PSA nadir greater than 1.0 ng/mL or a nadir plus 2 ng/mL underwent repeat biopsy to assess for cancer recurrence.

RESULTS

The median age was 68 years (range 48 to 78). The median preoperative PSA level was 6.0 ng/mL, and the postoperative PSA nadir was 2.4 ng/mL. The median follow-up was 28 months. Seventeen patients remained potent. No patients reported worsened lower urinary tract symptoms, incontinence, rectal pain, perineal discomfort, or fistula formation. The median PSA nadir was 2.4 ng/mL, and 40% of patients had a PSA nadir of less than 1.0 ng/mL. Of the 25 patients, 21 (84%) had not experienced biochemical failure, defined as a greater than 50% PSA nadir reduction. Seven patients underwent repeat biopsy, and prostate cancer was detected in the contralateral gland in 2 patients and in the area of previous cryosurgery in 1 patient.

CONCLUSIONS

Focal cryoablation of the prostate has exhibited minimal morbidity and promising efficacy in our 3-year observation. Longer follow-up is necessary to determine its role in the treatment of patients with low-risk unifocal prostate cancer.

Short-term cancer control after primary cryosurgical ablation for clinically localized prostate cancer using third-generation cryotechnology

OBJECTIVES

Percutaneous perineal cryoablation of the prostate is a promising technique in the treatment armamentarium for clinically localized prostate carcinoma. We report our initial experience using a transrectal ultrasound-guided, third-generation, argon/helium cryosurgical system.

METHODS

From January 2002 to July 2005, 50 men underwent primary cryosurgery for clinically localized prostate carcinoma. The median patient age was 68 years (range 50 to 83), and the median follow-up period was 18 months (range 3 to 43). According to the D'Amico risk stratification system, 36 patients (72%) had low-risk, 9 (18%) had intermediate-risk, and 5 (10%) had high-risk prostate cancer. All patients underwent a dual freeze-thaw cycle using third-generation cryotechnology with ultrathin 17-gauge cryoneedles.

RESULTS

The prostate-specific antigen (PSA) level for all patients at the last follow-up visit was less than 0.5 ng/mL in 45 patients (90%) and 0.5 ng/mL or more in 5 (10%). Two patients had persistent prostate cancer confirmed by prostate biopsy and were treated with salvage cryotherapy or external beam radiotherapy. Three other patients had an elevated PSA level after cryotherapy despite negative posttreatment biopsies and a metastatic evaluation. Of these 3 patients, 2 had their postcryotherapy PSA level normalize, and 1 patient, with intermediate-risk disease preoperatively, had a consistent increase in PSA up to 1.2 ng/mL. The overall survival rate was 100%.

CONCLUSIONS

Cryoablation of the prostate is a feasible and safe treatment option in patients with organ-confined prostate cancer. Additional studies with longer follow-up are necessary to determine the sustained efficacy of this procedure.

Cryosurgical technique: assessment of the fundamental variables using human prostate cancer model systems

Cryosurgery offers a promising therapeutic alternative for the treatment of prostate cancer. While often successful, complete cryoablation of cancerous tissues sometimes fails due to technical challenges. Factors such as the end temperature, cooling rate, duration of the freezing episode, and repetition of the freezing cycle have been reported to influence cryosurgical outcome. Accordingly, we investigated the effects of these variables in an in vitro prostate cancer model. Human prostate cancer PC-3 and LNCaP cultures were exposed to a range of sub-zero temperatures (-5 to -40 degrees C), and cells were thawed followed by return to 37 degrees C. Post-thaw viability was assessed using a variety of fluorescent probes including alamarBlue (metabolic activity), calceinAM (membrane integrity), and propidium iodide (necrosis). Freeze duration following ice nucleation was investigated using single and double freezing cycles (5, 10, and 20 min). The results demonstrated that lower freezing temperatures yielded greater cell death, and that LNCaP cells were more susceptible to freezing than PC-3 cells. At -15 degrees C, PC-3 yielded approximately 55% viability versus approximately 20% viability for LNCaP. Double freezing cycles were found to be more than twice as destructive versus a single freeze-thaw cycle. Both cell types experienced increased cell death when exposed to freezing temperatures for longer durations. When thawing rates were considered, passive (slower) thawing following freezing yielded greater cell death than active (faster) thawing. A 20% difference in viability between passive and active thawing was observed for PC-3 for a 10 min freeze. Finally, the results demonstrate that just reaching -40 degrees C in vitro may not be sufficient to obtain complete cell death. The data support the use of extended freeze times, multiple freeze-thaw cycles, and passive thawing to provide maximum cell destruction.

Cryotherapy for localised prostate cancer

BACKGROUND

Prostate cancer is a common cancer in elderly men and in some will prove fatal. Standard treatments for localised disease include surgery ( radical prostatectomy), radiotherapy and active monitoring. New emerging therapies are being evaluated with the aim of reducing the complication rate associated with standard therapies, as well as developing an effective treatment. One such modality is cryotherapy, a procedure that introduces probes directly into the prostate tumour and kills the malignant cells by a freezing process.

OBJECTIVES

This review aims to evaluate the relative clinical and economic benefits of cryotherapy compared to standard therapies for the primary treatment of localised prostate cancer.

SEARCH STRATEGY

Our search strategy included an electronic search of MEDLINE from 1996 to December 2006, plus EMBASE (Excerpta Medica Database), the Cochrane library, ISI Science Citation Index, Database of Abstracts and Reviews of Effectiveness (DARE), and LILACS to identify all relevant published randomised trials of cryotherapy for localised prostate cancer. Cancerlit and HealthSTAR databases were searched to their final date. Handsearching of relevant journals was undertaken.

SELECTION CRITERIA

Only published randomised trials comparing the effectiveness of cryotherapy with radical prostatectomy, radiotherapy or active monitoring for the primary treatment of men with localised prostate cancer were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Data were extracted from eligible studies, and included study design, participants, interventions and outcomes. Primary outcome measures were biochemical disease-free survival, disease-free survival and treatment-induced complications. Secondary outcomes included disease-specific survival, overall survival, quality-of-life outcome measures and economic impact measures.

MAIN RESULTS

There were no randomised trials found comparing cryotherapy with other therapies for the primary treatment of localised prostate cancer. All studies identified were case series. To indicate the level of the available evidence, studies that evaluated cryotherapy as a primary therapy, using transrectal ultrasound guidance and urethral warming in at least 50 patients with localised prostate cancer, and a minimum of one year follow up, were reviewed. Eight case series were identified that complied with these criteria; two were retrospective. The patients recruited (n = 1483) had an age range from 41 to 84 years, stages T1 = 0 to 43%, T2 = 24 to 88%, T3 = 1 to 41%, and T4 = 0 to 14%. The mean preoperative PSA level ranged from 9.7 to 39 ng/mL, with Gleason scores < 7 and ranging from 6 to 37%. One additional study that compared cryotherapy (total cryotherapy and standard cryotherapy with urethral preservation) with radical prostatectomy was also identified and reviewed. In this study the success rates, defined as a post-treatment PSA of 0.2 ng/mL or less, were reported as 96% for total cryotherapy, 49% for standard cryotherapy and 73% for radical prostatectomy. Four studies did not monitor the temperature of the cyro-procedure and reported 17 to 28% of patients had a positive biopsy following cryotherapy with a mean PSA nadir of 0.55 to 1.75 ng/mL (median 0.4 to 1.85 ng/mL). The other four studies used thermocouples to monitor the temperature of the cryo-procedure and reported progression-free survival rates of 71 to 89% with 1.4 to 13% of patients having a positive biopsy post-cryotherapy. At 5 years, overall survival was reported as 89 to 92% in two studies, and disease-specific survival as 94% in one study. The major complications observed in all studies included impotence (47 to 100%), incontinence (1.3 to 19%), and urethral sloughing (3.9 to 85%), with less common complications of fistula (0 to 2%), bladder-neck obstruction (2 to 55%), stricture (2.2 to 17%) and pain (0.4 to 3.1%). Most patients were sent home the following day (range 1 to 4 days).

AUTHORS' CONCLUSIONS

Cryotherapy offers a potential alternative to standard therapies for the primary treatment of localised prostate cancer. However, the poor quality of the available studies makes it difficult to determine the relative benefits of this modality. Randomised trials are needed to fully evaluate the full potential of cryotherapy in men with this disease. Patients selecting cryotherapy as their therapeutic option should be made fully aware of the reported efficacy, complications and the low-grade evidence from which these data are derived.