Prostate cryoablation using direct transperineal placement of ultrathin probes through a 17-gauge brachytherapy template-technique and preliminary results

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.

In vivo optoacoustic temperature imaging for image-guided cryotherapy of prostate cancer

The objective of this study is to demonstrate in vivo the feasibility of optoacoustic temperature imaging during cryotherapy of prostate cancer. We developed a preclinical prototype optoacoustic temperature imager that included pulsed optical excitation at a wavelength of 805 nm, a modified clinical transrectal ultrasound probe, a parallel data acquisition system, image processing and visualization software. Cryotherapy of a canine prostate was performed in vivo using a commercial clinical system, Cryocare^® CS, with an integrated ultrasound imaging. The universal temperature-dependent optoacoustic response of blood was employed to convert reconstructed optoacoustic images to temperature maps. Optoacoustic imaging of temperature during prostate cryotherapy was performed in the longitudinal view over a region of 30 mm (long)  ×  10 mm (deep) that covered the rectum, the Denonvilliers fascia, and the posterior portion of the treated gland. The transrectal optoacoustic images showed high-contrast vascularized regions, which were used for quantitative estimation of local temperature profiles. The constructed temperature maps and their temporal dynamics were consistent with the arrangement of the cryoprobe and readouts of the thermal needle sensors. The temporal profiles of the readouts from the thermal needle sensors and the temporal profile estimated from the normalized optoacoustic intensity of the selected vascularized region showed significant resemblance, except for the initial overshoot, that may be explained as a result of the physiological thermoregulatory compensation. The temperature was mapped with errors not exceeding  ±2 °C (standard deviation) consistent with the clinical requirements for monitoring cryotherapy of the prostate. In vivo results showed that the optoacoustic temperature imaging is a promising non-invasive technique for real-time imaging of tissue temperature during cryotherapy of prostate cancer, which can be combined with transrectal ultrasound-the current standard for guiding clinical cryotherapy procedure.

Cryosurgery, an alternative treatment option for organ-confined prostate cancer: current beliefs and practice patterns of urologists

PURPOSE

We aim to evaluate the current beliefs and practice patterns of urologists in regard to use of cryosurgery for management of PCa.

METHODS

An anonymous 13-point survey was designed and sent out to members of the Society of Urologic Oncology (SUO), Endourological Society (ES) and American College of Cryosurgery (ACC). Descriptive statistics and univariate analyses were used to determine variables associated with the use of cryosurgery.

RESULTS

Of the 206 responses received [81 (39.2 %) SUO; 106 (51.5 %) ES; 19 (9.2 %) ACC], 83 (40.3 %) performed cryosurgery. The majority of respondents who utilize cryosurgery do so in unilateral (80.3 %) and bilateral (77.6 %) intermediate-risk PCa. Also, users of this technology indicated significant use in primary treatment (>72 %), salvage treatment (>83 %), in patients who prefer cryosurgery (89.9 %) have a life expectancy ≥10 years (65.8 %) and poor erections (74.7 %). The main reason for not utilizing cryosurgery was the lack of technical expertise (56.7 %). A urologist in a non-academic practice setting was 3.2 times more likely to perform cryosurgery compared to a urologist in an academic setting, p = 0.0001.

CONCLUSION

Cryosurgery is increasingly being accepted among urologists. However, the need for large-scale studies as well as randomized clinical trials to further delineate the benefits of cryosurgery and convince the non-users and institutions cannot be overemphasized.

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 for Tumors — A Clinical Overview

Cryosurgery, a method of treating disease by the production of freezing temperatures in the tissue, is a useful technique for the treatment of tumors. When the modern era of cryosurgery began in the mid 1960's, the technique was used only for tumors easily accessible by direct observation or via endoscopy, such as those of the skin, oral cavity, and prostate gland. In general, the technique had limited usefulness in the next two decades. However, with the advent of intraoperative ultrasound as a method of monitoring the process of freezing and with the development of more effective cryosurgical apparatus, the cryosurgical treatment of tumors of the viscera and other deep tissues became practical in the 1990's. This review assesses the present day status of cryosurgery in the management of diverse tumors.

An efficient technique for estimating the two-dimensional temperature distributions around multiple cryo-surgical probes based on combining contributions of unit circles

This study presents an efficient, fast and accurate method for estimating the two-dimensional temperature distributions around multiple cryo-surgical probes. The identical probes are inserted into the same depth and are operated simultaneously and uniformly. The first step in this method involves numerical derivation of the temporal performance data of a single probe, embedded in a semi-infinite, tissue-like medium. The results of this derivation are approximated by algebraic expressions that form the basis for computing the temperature distributions of multiple embedded probes by combining the data of a single probe. Comparison of isothermal contours derived by this method to those computed numerically for a variety of geometrical cases, up to 15 inserted probes and 2-10 min times of operation, yielded excellent results. Since this technique obviates the solution of the differential equations of multiple probes, the computational time required for a particular case is several orders of magnitude shorter than that needed for obtaining the full numerical solution. Blood perfusion and metabolic heat generation rates are demonstrated to inhibit the advancement of isothermal fronts. Application of this method will significantly shorten computational times without compromising the accuracy of the results. It may also facilitate expeditious consideration of the advantages of different modes of operation and the number of inserted probes at the early design stage.

Dystrophic calcification of the prostate after cryotherapy

We present a previously undocumented complication of dystrophic calcification of the prostate after cryotherapy. An 87-year-old male presented with recurrent lower urinary tract infections and was found to have an obstructing large calcified mass in the right lobe of the prostate. Subsequently, he underwent transurethral resection of the prostate (TURP) and bladder neck with laser lithotripsy to remove the calculus. We propose that chronic inflammation and necrosis of the prostate from cryotherapy resulted in dystrophic calcification of the prostate. As the use of cryotherapy for the treatment of localized prostate cancer continues to increase, it is important that clinicians be aware of this scenario and the technical challenges it poses.

Low temperature plasma: a novel focal therapy for localized prostate cancer?

Despite considerable advances in recent years for the focal treatment of localized prostate cancer, high recurrence rates and detrimental side effects are still a cause for concern. In this review, we compare current focal therapies to a potentially novel approach for the treatment of early onset prostate cancer: low temperature plasma. The rapidly evolving plasma technology has the potential to deliver a wide range of promising medical applications via the delivery of plasma-induced reactive oxygen and nitrogen species. Studies assessing the effect of low temperature plasma on cell lines and xenografts have demonstrated DNA damage leading to apoptosis and reduction in cell viability. However, there have been no studies on prostate cancer, which is an obvious candidate for this novel therapy. We present here the potential of low temperature plasma as a focal therapy for prostate cancer.

A report on major complications and biochemical recurrence after primary and salvage cryosurgery for prostate cancer in patients with prior resection for benign prostatic hyperplasia: a single-center experience

OBJECTIVE

To report on biochemical recurrence (BCR) and major complications in patients with prior prostate resection that underwent cryosurgery (CS) for prostate cancer.

METHODS

The Columbia University Urologic Oncology database identified patients that underwent CS after resection. Patient demographics, surgical details, prostate volume, prostate-specific antigen (PSA) levels, biopsy results, major complications, and BCR were recorded.

RESULTS

Prior resection for benign prostatic hyperplasia was identified in 32 patients who underwent CS. Median age was 70.7 years (range 54.9-83.1 years). Median prostate volume before and after resection was 40 (range 30-90) and 20 cm(3) (range 9-54), respectively. Median time from resection to CS was 50.4 months (range 0-178.1 months). Twenty-one (16 full and 5 focal gland ablations) and 11 patients underwent primary and salvage CS, respectively. Median prostate-specific antigen at CS was 5.9 ng/mL (range 0.1-18.4 ng/mL), with a median nadir post-CS of 0.1 ng/mL (range 0.04-12.2 ng/mL). Median follow-up was 41.2 months (range 8.9-154.2 months). According to Stuttgart and Phoenix definitions, 11 and 10 patients, respectively, experienced BCR. Three patients underwent further CS for disease recurrence. Overall complications were rare and minor. Patients with smaller glands postresection (<20 cc(3)) experienced a similar incidence of BCR as those with larger glands after CS in all the settings.

CONCLUSION

Although no patients experienced major complications after primary CS, 18% (2/11) had grade III or higher complications in the salvage setting. Postresection gland volume was not associated with BCR. Further research is needed to evaluate functional and oncological outcomes in postresection patients after CS because they are considered high-risk for major complications.

Cryotherapy and its applications in the management of urologic malignancies: a review of its use in prostate and renal cancers

Cryotherapy has been established as an ablative modality for the treatment of a wide range of malignancies. Being minimally invasive, it is associated with less morbidity than conventional extirpative surgical procedures. In recent years, it has been used with success for treating two of the common urologic malignancies, that is, prostate and renal cancer. In this review, we highlight the role of cryotherapy as a treatment modality, the proposed destructive mechanisms of action and the risks of its use in the management of prostate and renal malignancy.

Generating prostate models by means of geometric deformation with application to computerized training of cryosurgery

PURPOSE

As a part of an ongoing project to develop computerized training tools for cryosurgery, the objective of the current study is twofold: to compile literature data on the likelihood of cancer tumor growth and its effect on the prostate shape and to present a deformation scheme for a 3D organ template in order to generate clinically relevant prostate models. The long-term objective of this study is to develop a database of prostate models for computerized training.

METHODS

Cryosurgery is typically performed on patients with localized prostate cancer found in stage T3 or earlier. The distribution of key geometric features likely to be found in the prostate at stage T3 is integrated into a 3D prostate template by employing the extended free-form deformation (EFFD) method. The applied scheme combines two steps: pre-selecting a set of geometric parameter values and manipulating the lattice control points until the prostate model meets the desired criteria.

RESULTS

Examples for model generation are displayed, based on two 3D prostate templates previously obtained from ultrasound imaging. These examples include selected cases with unilateral and bilateral stage T3 tumor growth, suitable for incorporation into a training database.

CONCLUSIONS

EFFD is an efficient method for rapid generation of prostate models. The compiled criteria for model generation do not lead to a unique shape since the contours for template deformation are randomly selected. Nevertheless, these criteria do lead to shapes resembling cancer growth, as various growth histories can lead to a tumor characterized by the same key parameter values.

Comparison of biochemical failure definitions for predicting local cancer recurrence following cryoablation of the prostate

BACKGROUND

Various definitions of biochemical failure (BF) have been used to predict cancer recurrence following prostate cryoablation. However to date, none of these definitions have been validated for this use. We have reviewed several definitions of BF to determine their accuracy in predicting biopsy-proven local recurrence following prostate cryoablation.

METHODS

The Columbia University Urologic Oncology Database was queried for patients who underwent prostate cryoablation between 1994 and 2010, and who subsequently underwent surveillance biopsy due to clinical suspicion of prostate cancer recurrence. Serial postoperative prostate-specific antigen (PSA) results were used to determine BF according to various definitions of BF. Biopsy results were used to determine local recurrence. Sensitivity, specificity, positive and negative predictive value, and receiver operating characteristic (ROC) curve area were calculated for each of the BF definitions.

RESULTS

A total of 110 patients met inclusion criteria for the study. These patients were treated with primary full-gland (n = 38), primary focal (n = 24), or salvage cryoablation (n = 48). On surveillance biopsy, 66 patients (60%) were found to have locally recurrent prostate cancer. The most accurate BF definition overall was PSA nadir plus 2 ng/ml (Phoenix definition), with sensitivity, specificity, and ROC curve area of 68%, 59%, and 0.64, respectively.

CONCLUSIONS

Overall, the Phoenix definition best predicted local cancer recurrence following prostate cryoablation. These preliminary data may be useful for researchers evaluating the short-term efficacy of cryoablation, and for urologists assessing their patients for potential cancer recurrence.

Focal therapy in the management of prostate cancer: an emerging approach for localized prostate cancer

A widespread screening with prostate-specific antigen (PSA) has led increased diagnosis of localized prostate cancer along with a reduction in the proportion of advanced-stage disease at diagnosis. Over the past decade, interest in focal therapy as a less morbid option for the treatment of localized low-risk prostate cancer has recently been renewed due to downward stage migration. Focal therapy stands midway between active surveillance and radical treatments, combining minimal morbidity with cancer control. Several techniques of focal therapy have potential for isolated ablation of a tumor focus with sparing of uninvolved surround tissue demonstrating excellent short-term cancer control and a favorable patient's quality of life. However, to date, tissue ablation has mostly used for near-whole prostate gland ablation without taking advantage of accompanying the technological capabilities. The available ablative technologies include cryotherapy, high-intensity focused ultrasound (HIFU), and vascular-targeted photodynamic therapy (VTP). Despite the interest in focal therapy, this technology has not yet been a well-established procedure nor provided sufficient data, because of the lack of randomized trial comparing the efficacy and morbidity of the standard treatment options. In this paper we briefly summarize the recent data regarding focal therapy for prostate cancer and these new therapeutic modalities.

Percutaneous MR-guided cryoablation of prostate cancer: initial experience

OBJECTIVE

We report our initial experience and the technical feasibility of transperineal prostate cryoablation under MR guidance.

METHODS

Percutaneous MR-guided cryoablation was performed in 11 patients with prostatic adenocarcinoma contraindicated for surgery (mean age: 72 years, mean Gleason score: 6.45, mean prostate-specific antigen (PSA): 6.21 ng/ml, T1-2c/N0/M0, mean: prostate volume 36.44 ml). Free-hand probe positioning was performed under real-time MR imaging. Four to seven cryoprobes were inserted into the prostate, depending on gland volume. The ice ball was monitored using real-time and high-resolution BLADE multi-planar imaging. Patients were followed at 1, 3, 6, 9 and 12 months after the procedure with serum PSA level and post-ablation MRI.

RESULTS

Prostate cryoablation was technically feasible in 10/11 patients. The ice ball was clearly and sharply visualised in all cases as a signal-void area. Mean ice-ball volume was 53.3 ml. Mean follow-up was 15 months (range: 1-25). Mean PSA nadir was 0.33 ng/ml (range: 0.02-0.94 ng/ml). Mean hospitalisation was 5 days (range: 3-13). Complications included a urethro-rectal fistula, urinary infection, transient dysuria and scrotal pain.

CONCLUSIONS

MR-guided prostate cryoablation is feasible and promising, with excellent monitoring of the ice ball. Future perspectives could include the use of MR guidance for focal prostate cancer cryotherapy.

KEY POINTS

• Magnetic resonance allows precise positioning of cryoprobes with real-time imaging. • High-resolution MRI allows excellent monitoring of the developing ice ball. • Cryoablation of prostate cancer under MR guidance is technically feasible. • Further work will refine the procedure and make it even safer.

Contemporary technique of intraoperative 3-dimensional ultrasonography-guided transperineal prostate cryotherapy

Successful cryotherapy of the prostate for neoplasms relies on imaging to achieve good oncological outcomes with minimal complications. Traditional prostatic cryotherapy relies on 2-dimensional ultrasonography (2DUS) guidance, which often makes it difficult to track the passage of needles in an oblique plane. We describe our initial 3-dimensional ultrasonography (3DUS) system, and the subsequent improvements that have been made during the last 10 years. Our imaging system uses a Philips HDI 5000 ultrasonography unit, a standard PC, a Matrox Meteor II video frame grabber and 3DUS developed at Robarts Research Institute. For the cryotherapy we use ultrathin (17-gauge) IceRod needles. After image acquisition, preplanning is performed using the 3-dimensional (3D) software, and then the IceRod needles are inserted into the prostate. As the freezing process commences, continuous 3DUS images are taken and analyzed during the double freeze-thaw cycles to monitor the progress of the ice ball formation. Real-time intraoperative 3D imaging of the prostate during cryotherapy has allowed us to accurately preplan and then monitor the progression of ice ball formation, which represents a significant advantage over conventional 2DUS.

Percutaneous cryoablation of small hepatocellular carcinomas using a 17-gauge ultrathin probe

AIM

To evaluate the feasibility and safety of percutaneous cryoablation (PCA) of small hepatocellular carcinomas (HCCs) using a 17 G ultrathin cryoprobe.

MATERIALS AND METHODS

Twenty patients (male:female ratio14:6) with 20 HCCs, who were not surgical candidates, underwent ultrasound (US)-guided PCA for treatment of HCCs. Single HCCs less than 3cm in diameter were included in this study. Ablation was performed using a 17 G cryoprobe. The effectiveness was determined by the changes in alpha-foetoprotein level and degree of tumour necrosis on follow-up computed tomography (CT); complete response (100% necrosis), partial response (100%>necrosis≥30%), stable disease (any cases not qualifying for either partial response or progressive disease) and progressive disease (increase of at least 20% in diameter of viable tumour). Haemoglobin, white blood cell count (WBC), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and total bilirubin were compared before and after the procedure, and the technical feasibility, complications, clinical outcomes and survival of each patient were also evaluated.

RESULTS

All procedures were technically successful. Each patient complained of negligible pain and there was no other procedure-related complication or mortality. The mean level of alpha-foetoprotein declined significantly from 53.2 to 20.4ng/ml 1 month after the procedure (p<0.05). At 1-month follow-up CT, there were 13 complete responses, four partial responses, three patients with stable disease, and no patients had progressive disease. Six of seven lesions that did not present with a complete response underwent further treatment. On long-term follow up (6-30 months; mean 20.7), a local recurrence was seen in one of 13 lesions (8%) with complete response revealed. Laboratory findings showed no significant changes except for the transient increase of SGOT and SGPT.

CONCLUSION

US-guided PCA using a 17 G cryoprobe was feasible and safe for the treatment of HCC smaller than 3cm.

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.

Predicting biopsy-proven prostate cancer recurrence following cryosurgery

OBJECTIVES

Prostate cancer (CaP) cryosurgery utilizes PSA nadir level and radiotherapy criteria as surrogates for success. We attempted to correlate PSA doubling time (PSAdt) and time of undetectable PSA (TUPSA) with biopsy-proven cancer recurrence (BPR) in men treated with primary third-generation cryotherapy for clinically localized CaP.

MATERIALS AND METHODS

Demographic, clinical, and pathologic data was retrieved including age, race, use of preoperative hormones or 5-α reductase inhibitors (5-ARIs), initial biopsy PSA, biopsy Gleason score, cT stage, prostate volume, presence/absence median lobe, and follow-up. Post-cryotherapy biopsy was considered for PSA levels ≥ 0.5 ng/ml. PSAdt was determined by the log-slope method. TUPSA was defined as time from surgery to a PSA value ≥ 0.2 ng/ml or most recent follow-up if undetectable.

RESULTS

Ninety-seven patients were identified. Preoperative hormonal manipulation was used in 25 (26%); 5 (5%) were using a 5-ARI. Twenty-seven (29%) underwent post-cryotherapy biopsy, 12 (12%) had a BPR. In 41 (42%), PSAdt was calculated (median 11.9 months, IQR 6.6-34.8); no significant difference between patients with BPR and without CaP was found (P = 0.46). TUPSA was a median of 4.9 months (IQR 3.2-9.9) vs. 15.6 months (IQR 6.1-30.3) for BPR or no CaP, respectively (P = 0.005). On proportional hazards regression, TUPSA was the only independent predictor of BPR (P = 0.03, OR 0.91).

CONCLUSIONS

Post-cryosurgery PSAdt does not appear to be associated with BPR risk, whereas TUPSA reduces the risk of BPR by 9% per month. This may help guide management if local failure is suspected.

Salvage cryotherapy: is there a role for focal therapy?

Prostate cancer treatment has undergone vast development over the last few decades, but the most notable changes have included nerve-sparing open radical prostatectomy, laparoscopic radical prostatectomy, including robot-assisted and, more recently, cryotherapy and high-intensity focused ultrasound (HIFU). While radical surgery is the current gold standard, the less invasive therapeutic options of cryotherapy and HIFU are regarded as largely experimental by governing bodies. In the case of cryotherapy, a wealth of experience has been accumulated demonstrating its efficacy. Initially used as a salvage treatment for radiation-failed prostate cancer, cryotherapy has been widely used as a primary treatment for localized and locally advanced prostate cancer. More recently, there has been interest expressed in the concept of focal therapy in prostate cancer. This has been evaluated as a primary treatment for prostate cancer, but little information is available regarding the potential use as a salvage treatment. In this article, we evaluate the potential for focal treatment in the salvage setting.

Correlation of thermocouple data with voiding function after prostate cryoablation

OBJECTIVES

To identify possible correlations of thermocouple recorded data with altered postoperative voiding function after prostate cryosurgery.

METHODS

A retrospective analysis of the records of 58 patients treated with prostate cryoablation from October 2005 through April 2009 was conducted. Multivariate analysis of patient age, presenting prostate-specific antigen level, Gleason score, clinical T stage, prostate volume, maximum low temperature thermocouple recordings, history of radiation and or hormonal therapy, were studied as possible correlative factors for altered postoperative voiding function.

RESULTS

Of 58 patients, 22 (37.9%) manifested postcryoablation urgency and frequency (n = 13) requiring medical therapy or retention (n = 9). On multivariate analysis, age (P = .037) and an external sphincter temperature < or = 23 degrees C (P = .012) were associated with voiding frequency, urgency, or retention (odds ratio = 6.26, 95% CI: 1.62-24.16), whereas anterior rectal wall temperature (Denon) was weakly associated (P = .079).

CONCLUSIONS

Thermocouple data provide an objective means of assessing cryosurgical outcomes. This is the first report of a correlation of such data to post-treatment voiding function. A total of 37.9% of patients experienced urgency and/or frequency or urinary retention after cryoablation of the prostate for localized disease. Older age and external sphincter temperature < or = 23 degrees C were statistically significant predictors of these events. The data suggest that limiting the degree of freezing at the external sphincter may decrease procedure related morbidity. Further study is warranted to better delineate temperature-related data on treatment outcomes.

[Cryoablation of localized prostate cancer. Current state]

Due to continuous technical developments for more than half a century followed by better clinical results with minimal side effects, cryoablation of the prostate for localized prostate cancer has evolved as a true alternative therapeutic option in selected cases. The current version of cryoablation has almost nothing in common with those versions established in the 1960s and 1970s and further developed in the 1980s and 1990s. The present version is minimally invasive and has a high efficacy for treatment of high risk carcinomas and failure of other therapeutic modalities. Cryoablation of the prostate is indicated if there are absolute or relative contraindications for radical surgery. In salvage cases cryoablation is the therapy of choice for localized prostate cancer. Standardization of the procedure, definition of freeze-thaw cycles and structured training programs have led to this status.

Combined cryoablation and GM-CSF treatment for metastatic hormone refractory prostate cancer

A total of 12 patients with metastatic hormone refractory prostate cancer were treated by combining cryoablation and granulocyte macrophage colony-stimulating factor administration. Besides prostate-specific antigen (PSA) measurements, peripheral blood mononuclear cells were also obtained; the frequency of tumor-specific T cells was tested ex vivo in an interferon-gamma enzyme-linked immunospot assay after stimulating with autologous prostate cancer-derived protein lysates. To assess cytolytic activity, T cells were coincubated with human prostate cancer cells (LNCaP) or renal cancer cells (GRC-1), and release of cytosolic adenylate kinase was measured by a luciferase assay. The median PSA decline percentage was 69.4% (range: 30.5% to 92.5%) and the median time to the nadir PSA was 4 months after therapy (range: 3 to 6). The median time to disease progress was 18 months, and 1 patient obtained a 92.5% PSA decline and a greater than 50% reduction of lung disease and survived 31 months. Four or 8 weeks after treatment, the tumor-specific T-cell responses were increased in peripheral blood mononuclear cell. The cytolytic activity against LNCaP was also increased significantly whereas no response was found against GRC-1. It seemed that there was no direct correlation between the degree of T-cell response and decline in PSA. Combined cryoablation with granulocyte macrophage colony-stimulating factor treatment was suggested to be an alternative approach for metastatic hormone refractory prostate cancer and could induce tumor-specific immunologic response.

Prospective comparison of five mediators of the systemic response after high-intensity focused ultrasound and targeted cryoablation for localized prostate cancer

OBJECTIVE

To evaluate whether high-intensity focused ultrasound (HIFU) is less invasive than targeted cryoablation of the prostate (TCAP), as experimental studies suggest that the acute-phase reaction is proportional to surgery-induced tissue damage.

PATIENTS AND METHODS

Between May 2004 and December 2007, 127 consecutive patients undergoing HIFU (71) or TCAP (56) in our departments were assessed prospectively. Blood samples were collected 24 h before (T0), during surgery (T1), at the end of anaesthesia (T2), and at 12 (T3), 24 (T4) and 36 h after surgery (T5). The extent of the systemic response to surgery-induced tissue trauma was measured by assessing the levels of acute-phase markers tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-10, C-reactive protein (CRP) and serum amyloid A (SAA), at all sampling times in all patients.

RESULTS

The median (interquartile range) age in the HIFU and TCAP groups was 70 (62-77) and 68 (59-75) years, respectively (P = 0.4). Baseline levels (T0) of TNF-alpha, IL-6, IL-10, CRP and SAA were comparable in both groups. The levels of all four markers increased during both procedures; the median values were higher for TCAP at T2 (P = 0.02, 0.001, <0.001 and 0.06), T3 (P < 0.001, 0.009, 0.003 and 0.001), T4 (P = 0.007, <0.001, 0.005 and <0.001) and T5 (P < 0.001, 0.004, <0.001 and 0.02), respectively. IL-6 was also higher for TCAP at T1 (P = 0.03). IL-10 did not change at the different sampling times.

CONCLUSION

The tissue trauma and associated invasiveness of HIFU is less than that of TCAP, based on the variables objectively measured in this study.

Immunologic response to primary cryoablation of high-risk prostate cancer

OBJECTIVE

To assess whether a specific cytotoxic T-cell response can be induced in patients with prostate cancer after cryoablation.

MATERIAL AND METHODS

Twenty Patients with high-risk prostate cancer underwent cryoablation. Blood was sampled prior to, 4 and 8 weeks after treatment. Serum cytokine levels were analyzed by ELISA, and the Th1/Th2 ratio was estimated from the IFN-gamma/IL-4 ratio. Peripheral blood mononuclear cells (PBMC) were stimulated with autologous prostate cancer-derived protein lysates, and frequency of tumor-specific T-cells was tested ex vivo in an IFN-gamma ELISPOT assay. To assess cytolytic activity, T-cells were co-incubated with human prostate cancer cells, LNCaP, or with renal cancer cells, GRC-1, and release of cytosolic adenylate kinase was measured by a luciferase assay.

RESULT

4 weeks after cryoablation significantly higher levels of TNF-alpha and IFN-gamma were observed compared to before treatment, and to 8 weeks after treatment. No changes in IL-4 or IL-10 were observed. The Th1/Th2 ratio (10.47+/-0.80), 4 weeks after treatment, was increased compared to before treatment (3.98+/-0.45), but decreased 8 weeks later (7.65+/-0.64). Tumor-specific T-cell responses were evident after cryosurgery in PBMC. Cytolytic activity against LNCaP was increased 4 weeks after treatment compared to before treatment (594.49+/-154.84 versus 4.20+/-0.68, P<0.01), but was decreased 8 weeks later (79.70+/-18.73). No response was found in cytolytic activity against GRC-1.

CONCLUSION

Cryoablation of prostate cancer can improve tumor-specific cytotoxic T-cell stimulation with a dramatically increased tumor specific cytolytic activity. However, the response is not sufficiently maintained to prevent cancer relapse.

Percutaneous renal cryoablation: current status

Over the last 13 years, renal cryoablation has emerged as a promising technique for the treatment of solid renal tumors. The improvement in imaging modalities such as ultrasound, computed tomography and MRI, as well as the introduction of thinner probes, has led to the spread of the minimally invasive percutaneous approach. We review the historical background of percutaneous renal cryoablation (PRC), present its basic principles, mention the contemporary clinical data and outcomes of this technique and suggest future directions for its wider application in renal tumors. Early results have demonstrated that it may offer an alternative for the treatment of small renal masses with the advantages of minimal complications, spared renal function, decreased overall costs and equivalent oncologic efficacy. Long-term results are required in order to apply this minimally invasive technique to a broader spectrum of patients.

High intensity focused ultrasound vs. cryotherapy as primary treatment for prostate cancer

Prostate cancer is one of the most commonly diagnosed cancers. Here, we will be discussing two upcoming techniques for its management. One is cryotherapy which has returned from oblivion after nearly 150 years armed with latest technology and looking as if its full potential has been recognized now. On the other hand is high intensity focused ultrasound (HIFU), the application of ultrasound to this field is relatively new and hence a lot of excitement and hope.We searched MEDLINE (PubMed 1942-2005), reference lists of retrieved articles, urology textbooks and our own data looking for studies comparing cryotherapy and HIFU. From 81 titles or abstracts, two independent reviewers identified 50 as potentially relevant. Disagreement was resolved by discussion involving the third reviewer and we finally identified 45 articles. Full reports of 45 articles were retrieved and final selection was made by the same two independent reviewers using the same criteria as for the initial selection. Data were extracted and methodological qualities of selected studies were reviewed by two independent reviewers. Qualitative analysis and synthesis were done.Treatment options depend upon the age of patient, grade of tumor and expectations out of treatment. Patient choice governs the treatment actually to be given. It is the selection of a patient for a particular treatment option that decides how favorable the outcome is going to be. Both these techniques are relatively new and they look promising but both lack long-term data to prove their efficacy.

Ultrashort intracorporeally maneuverable cryoprobes for laparoscopic renal cryoablation in the porcine model

AIM

To determine the feasibility and efficacy of laparoscopic renal cryosurgery using a novel ultrathin ultrashort intracorporeal cryoprobe in a porcine model.

MATERIAL AND METHODS

Novel cryoprobes 4 cm in length and 1.5 mm in diameter were manipulated intracorporeally after insertion via a designated 15 mm laparoscopic port. Renal cryoablative lesions were induced laparoscopically in four 40 kg female piglets. We correlated between intraoperative temperature, ice ball geometry, intraoperative ultrasonographic properties, and histology.

RESULTS

Laparoscopic manipulation of the cryoprobes was straightforward. No port site bleeding occurred during insertion, freezing, thawing or upon removal of the probes. The 0 degrees C, -20 degrees C, and -40 degrees C isotherms were measured at 6, 8, and 12 mm from the probe circumferentially. Ice-ball volume stabilization as determined by ultrasound occurred after 10 min of activation. Lower temperatures were reached after 10 min of probe activation as compared with 5 min (ice ball diameter 30 mm, DeltaT = 13-21 degrees C). Using a second 10-min-long freeze cycle resulted in a 14-22 degrees C lower temperature within the ice ball compared to a single cycle. Full coagulative necrosis was noted in the areas between the inserted probes with an additional 1-2 mm circumferential rim of severe tubular damage and apoptosis.

CONCLUSIONS

Our novel cryoprobe can be used effectively and conveniently in laparoscopic renal cryosurgery. Considering the size of the cryogenic lesion, using a cluster of probes may be advisable.

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.

[Cryosurgical ablation as primary treatment in prostate cancer patients]

OBJECTIVE

Cryosurgical ablation (CSA) is one treatment option that has been developed and it is now recognised as a true therapeutic alternative in the treatment of localised disease. The aim of this paper is to present the preliminary experience with CSA in prostate cancer from the centre in Norway.

MATERIALS AND METHODS

A total of 132 patients with prostate cancer have been treated with CSA since September 2003. In 90 patients, CSA was the primary therapy used and these patients included those with low (LR; n=27), intermediate (IR; n=37) and high risk (HR: n=26) disease. Low risk patients were defined as those with T1a-T2a, NO, MO, Gleason score < or = 6 and prostate-specific antigen (PSA) <10 ng/ml. Intermediate risk were patients with T2b tumours or a PSA level of 10-20 ng/ml or Gleason score 7. High risk were defined as those with T2c tumours or Gleason score >7 or PSA >20 ng/ml. The remaining 42 patients either had locally advanced disease or had received salvage treatment after previous external beam radiation (EBRT), cryotherapy or hormone treatment. Patients were evaluated at 3 and 6 months and thereafter at 6 month intervals. A voiding history was taken and the following tests conducted: uroflowmetry, residual urine.

RESULTS

Results are presented for those patients receiving CSA as a primary therapy. Currently, the longest follow-up period is 42 months. The median observation period is 21 months and 39% of patients have been seen at the 24-month follow-up visit. No evidence of clinical progression has been observed in patients in the LR or HR group. Two patients in the IR group had clinical evidence of progression. The most common side effects seen during the first year post CSA were urinary tract obstruction and the need for removal of dead prostatic tissue or calcifications. Histological examination of the removed tissue did not shown evidence of prostate cancer. All patients in the LR and IR group that were sexually active before treatment were also sexually active on last follow-up, 37% using some kind of aid. 86% of patients in the LR and IR groups reported no bother as to sexual function.

CONCLUSIONS

CSA is now recognised by the EAU as a true therapeutic alternative for the treatment of prostate cancer. Many institutions offer CSA only to older patients due to the lack of long-term data. If longer follow-up data confirm the short-term effect seen in my series, and if comparable side effects are reported in other studies, CSA might also be offered as primary treatment to younger patients.

New Modality for Maximizing Cryosurgical Killing Scope While Minimizing Mechanical Incision Trauma Using Combined Freezing-Heating System

Cryosurgery is a minimally invasive surgical technique using extremely low temperature to destroy undesired tissues. A surgical freezing margin of at least 1 cm is often recommended to avoid local tumor recurrence after surgery. For treating slender or elongated solid tumors in a conventional cryosurgery, simultaneous insertion of multiple cryoprobes is a necessity to guarantee an adequate killing scope. However, the risk of mechanical incision trauma may outweigh the benefits of such therapy. To resolve this difficulty, we proposed a new cryosurgical treatment modality, which can significantly maximize the killing scope while minimize the incision trauma, using the recently developed combined cryosurgical-hyperthermia treatment system (CCHTS). The method, named as one time’s percutaneous insertion while multiple times’ freezing∕heating ablation, is rather flexible in administrating a complex cryosurgical process and avoids certain shortcomings of conventional freezing strategies. Owing to the powerful heating function, the present probe can be easily moved back along its original incision tract to the desired positions immediately after initiating the heating. Then, a new iceball can be formed there while the iceballs generated before still remain unmelted in the following cycles. Consequently, a slender iceball could be generated to embrace the whole elongated tumor. This is, however, rather hard to achieve for a conventional cryosurgery with only one single freezing function or using only one probe. To visually demonstrate the feasibility and potential advantage of the present method, proof of concept in vitro gel experiments were performed. In addition, tests and corresponding theoretical simulations were performed on pork tissues. All the results indicate that the elongated iceball could be easily generated by using only one CCHTS probe owing to its strong freezing∕heating capability. In this way, a large number of incisions with multiple probes, commonly adopted in a conventional cryosurgery, can be avoided and the serious mechanical trauma including potential dangers can thus be significantly reduced. Meanwhile, the cost for the operation and postmedical care will be lowered. The present strategies are expected to be valuable in administrating a highly efficient and minimally invasive cryosurgery in the near future.

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.

Isothermal volume contours generated in a freezing gel by embedded cryo-needles with applications to cryo-surgery

Three-dimensional numerical simulations of multi-cryo-needle surgery were performed with cryo-needle temperature variations taken from matched experimental data. The transient temperatures and frozen volumes generated by simultaneously operating up to three 1.47 mm OD cryo-needles embedded in a phase-changing gel simulating the properties of biological tissues, were studied. In all cases studied, the volumes enclosed by the "lethal", -40 degrees C isotherm, achieved most of their final size in the first few minutes of operation, thus obviating the need for long application times. After 30 min of application of the one-, two- or three-cryo-needles, the ablation ratio attained 3%, 3-6% and 3-8%, respectively, depending on cryo-needle placement configurations. Synergistic effects of using multi-cryo-needles were reflected in the increased expansion of both the radial and axial locations of the isothermal contours. Within each number of cryo-needles used, however, the differences in these locations were rather small, and, as a general rule, tended to somewhat decrease with increasing the placement "density" of the cryo-needles. For each two- and three-cryo-needle application, there is a certain combination of placement configuration and application time that would produce the largest, temperature-specific, volume. As a general guideline, multiple cryo-needles should not be placed too close to each other in order to enhance their synergistic effect. Results of this study should be useful in the design of cryo-needle placement and operation protocols and in understanding the limitations of the freezing-ablation process.

Update on cryotherapy for prostate cancer in 2006

PURPOSE OF REVIEW

With the recent introduction of novel, minimally invasive procedures for the treatment of prostate cancer, cryotherapy has become a feasible option as a viable alternative to traditional radical surgery and radiation therapy. In this review we update recent data concerning the basic science of cryobiology, technical trends, oncologic results and complications of this procedure.

RECENT FINDINGS

As a result of better understanding of tumor cryodestruction at a molecular level, refinements in cryotechniques and improved patient selection, the results of cryotherapy are becoming more promising. Furthermore, the dramatic decrease in the number of complications after modern cryotherapy leads to a better quality of life, which may be a preferable option, especially for elderly patients with comorbidities. Current trends towards nerve-sparing and focal cryoablation are also discussed. Recent advances in cryobiology open up new opportunities to apply cryotherapy in combination with chemotherapy or radiotherapy for patients with intermediate or high-risk cancers.

SUMMARY

Potential directions for future developments in cryosurgery include concepts to reduce side effects such as minimizing cryodamage of the neurovascular bundles (nerve-sparing procedure), and focal ablation of a specific tumor site in patients in whom saturation biopsy supports unifocal prostate cancer.

Third-generation cryotherapy for prostate cancer in the UK: a prospective study of the early outcomes in primary and recurrent disease

OBJECTIVE

To present the early results of the use of third-generation cryotherapy in primary and recurrent prostate cancer at one UK centre.

PATIENTS AND METHODS

Over a 14-month period 51 patients underwent cryotherapy for prostate cancer. In 31 patients cryotherapy was used as the primary treatment and in 20 as a salvage treatment after radiotherapy or hormone ablation. Data were collected prospectively and the median follow-up was 9 months.

RESULTS

The prostate-specific antigen (PSA) level decreased to <0.5 ng/mL in 79% of patients undergoing primary treatment and in 67% of patients undergoing salvage treatment. A higher Gleason grade and PSA levels were associated with a poorer outcome. No patient developed a fistula, 4% developed urinary retention requiring transurethral prostatectomy and 4% had persistent incontinence. The rates of erectile dysfunction were high (86%). The median inpatient stay was 2 days.

CONCLUSION

Early results suggest that cryotherapy offers a safe alternative for primary and recurrent prostate cancer, particularly for older and less fit patients. Long-term data are required to assess the durability of response and the effect on survival.

Cryosurgery for prostate cancer

This article describes a new minimally invasive treatment for men with recurrent cancer post radiotherapy and localised prostate cancer utilising argon and helium gases. Cryosurgery utilises high pressure argon and helium gas linked by a computer-controlled delivery system to cryoneedles which are introduced through the perineum into the prostate gland. Transrectal ultrasound allows accurate placement of the needles. Temperature needles are used to protect the sphincter muscle and rectum.

Feasibility of nerve-sparing prostate cryosurgery: applications and limitations in a canine model

BACKGROUND AND PURPOSE

In a canine model, we evaluated the feasibility of nerve-sparing cryosurgery by active warming of the neurovascular bundle (NVB). Furthermore, our aim was to determine if NVB warming increases the risk of acinar gland and stromal-tissue preservation in adjacent areas of the prostate. The effects of a single versus double freeze-thaw cycle on prostate tissue were also assessed.

MATERIALS AND METHODS

Ten prostate lobes from five dogs were evaluated. Nine lobes from five dogs were treated with cryoablation using 17-gauge gas-driven cryoneedles. Seven lobes wre treated with active warming of the NVB using helium gas, and two lobes were treated without active warming. A single or double freeze-thaw cycle was utilized. Prostate tissue ablation and NVB preservation were evaluated in histologic sections.

RESULTS

All seven prostate lobes treated with active warming demonstrated complete or partial NVB preservation. Four of these lobes had adjacent gland preservation. All lobes treated with a double freeze-thaw cycle showed complete and uniform ablation of prostate tissue. One of the three lobes treated with a single freeze-thaw cycle demonstrated incomplete ablation of the tissue.

CONCLUSIONS

This is the first study investigating the feasibility of NVB preservation under controlled experimental conditions. In our canine model, NVB preservation with active warming was possible but not consistently reproducible. In some cases, NVB preservation with active warming may result in incomplete peripheral tissue ablation. A double, but not a single, freeze-thaw cycle induces complete and effective necrosis of prostatic tissue. These results have significant clinical applications when attempting nerve-sparing cryosurgical ablation of the prostate.

The current role of cryotherapy for renal and prostate tumors

Minimally invasive treatments continue to evolve as an alternative method for the treatment of kidney and prostatic tumors. Of the mainstream ablative procedures reported in the literature, the cryotherapy data appear to be the most durable. Currently, select kidney and prostatic lesions are treated using cryotherapy. Although limited long-term survival data using cryotherapy are available, recent series have provided compelling results, promoting interest in renal and prostatic cryoablation. This article assesses the current status of cryotherapy in urology, specifically the indications, techniques, and clinical results in treating kidney and prostate tumors.

Tissue ablation technologies for localized prostate cancer

Traditional treatments for men with localized prostate cancer have included both surgical removal and radiation therapy, with their potential adverse effects on patient quality of life. Thus, there has been increasing interest in the development of minimally invasive procedures that use various technologies to deliver lethal doses of heat or cold to the prostate in an attempt to kill cancer cells. At the same time, it is vital that these newer techniques ablate prostate tissue and spare vital periprostatic organs essential for maintaining function and quality of life. In this article, we evaluate the current status of tissue ablation modalities in the treatment of clinically localized prostate cancer, focusing on the different methods, early results, and possible future directions. Although still in the beginning stages, these newer forms of treatment offer exciting potential for first-line and second-line treatment of this common urologic malignancy.