Transrectal Ultrasound-Guided Transperineal Cryoablation in the Treatment of Prostate Carcinoma: Preliminary Results

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.

MR imaging of treated prostate cancer

Many management options are available to patients with newly diagnosed prostate cancer. Magnetic resonance (MR) imaging plays an important role in initial staging of prostate cancer, but it also aids in tumor detection when there is clinical or biochemical suspicion of residual or recurrent disease after treatment. The purpose of this review is to describe the normal appearances of the prostatic region after different kinds of treatment for prostate cancer and to discuss how these appearances differ from those of recurrent and residual disease. Several MR imaging techniques used in evaluating patients with prostate cancer are described, including conventional MR imaging sequences (mainly T1- and T2-weighted sequences), MR spectroscopic imaging, diffusion-weighted imaging, and dynamic contrast agent-enhanced MR imaging. Clinical considerations, together with the different approaches for interpreting serum prostate-specific antigen values in the posttreatment setting, are also presented. All forms of treatment alter the MR imaging features of the prostatic region to a greater or lesser extent, and it is important to be able to recognize expected posttreatment appearances and distinguish them from the features of recurrent or residual cancer to aid subsequent clinical management.

Endoscopic cryosurgery of the thyroid and parathyroid

In this study we looked at the efficacy of cryosurgery for thyroid and parathyroid tissue ablation in the porcine model. An endoscopic neck approach was successfully used in six 25 kg pigs. T4, free T4 and calcium serum levels were measured pre- and post-operatively. Gross and histologic examination of the glands and surrounding tissue were performed on postoperative Day 40. Postoperative T4, free T4 and calcium levels were not significantly different from preoperative values. Gross examination of the thyroid showed scar tissue in the region that underwent cryosurgery. Parathyroid that was frozen was replaced by scar tissue. Histologic examination of the glands confirmed the gross findings. Trachea, vagus nerve and carotid artery were also resected, and no changes were noted on histological examination. There was no damage to the surrounding tissues after cryosurgery. Directed cryosurgery of the thyroid and parathyroid is safe and feasible in this model.

Sonographic imaging of the puborectalis

INTRODUCTION

The aim of the present study was to compare the appearance of the normal male puborectalis using transrectal ultrasound with anatomy examinations to enhance the understanding of the relationship of the prostate to the adjacent pelvic floor. This information may help prevent damage to the puborectalis during transperineal ultrasound-guided biopsies and interventional therapies.

METHODS

Ten formalin-fixed cadavers were dissected to examine the appearance and structure of the puborectalis and its relationship with the peripheral organs. The puborectalis was also observed in a fresh male cadaver using transrectal ultrasound. In the fresh male cadaver, the puborectalis was located using transrectal sonography, the muscle was confirmed by anatomy, and the thickness was measured.

RESULTS

The ultrasonographic observations of the location of the puborectalis were confirmed by anatomy for the fresh cadaver. Bilateral, symmetrical, hypoechoic strips were observed beside the prostate in cross-section, and strip fibers were observed in the longitudinal section. The right and left puborectalis thickness measurements were 6.1 and 6.2 mm, respectively, in the sonographic image, and the measurements were 5.85 and 5.89 mm, respectively, in the formalin-fixed fresh cadaver.

CONCLUSIONS

Transrectal ultrasound provides a new imaging method to observe the male puborectalis, establishing a foundation for recognizing pelvic floor abnormalities with ultrasonography in the future.

[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.

PSA progression following radical prostatectomy and radiation therapy: new standards in the new Millennium

Prostate-specific antigen (PSA) progression following radical treatments of clinically localized prostate cancer is a common problem facing both the patient and the urologist. Not all patients with relapsing disease have an equal risk of death due to prostate cancer. After surgery, biochemical failure can be defined as persisting detectable levels of PSA after radical prostatectomy or a PSA rise after a period of normalization. On the other hand, definitions of PSA progression after radiation therapy vary and no clear consensus can be found. This review of the recent international literature updates the knowledge about the diagnostic procedures used in relapsing patients. Predictors of progression are precised leading to a better patient selection, based on currently available tables and nomograms. Indeed, identification of high risk patients may allow a more appropriate treatment decision. After radical treatment, the analysis of time to recurrence, PSA doubling time, PSA kinetics combined to modern imaging techniques such as 111In capromab penditide scan may allow a better identification of the recurrence site. Thus, an optimal treatment strategy may be envisaged such as local irradiation, salvage surgery, hormone therapy or combinations for which indications and results are provided. Alternative options such as cryotherapy still need further investigation. At last, the use of artificial neural networks will certainly enhance the selection of patients submitted to radical treatments as well as the selection of relapsing patients to allow a more appropriate adjuvant therapy.

Combined magnetic resonance imaging and spectroscopic imaging approach to molecular imaging of prostate cancer

Magnetic resonance spectroscopic imaging (MRSI) provides a noninvasive method of detecting small molecular markers (historically the metabolites choline and citrate) within the cytosol and extracellular spaces of the prostate, and is performed in conjunction with high-resolution anatomic imaging. Recent studies in pre-prostatectomy patients have indicated that the metabolic information provided by MRSI combined with the anatomical information provided by MRI can significantly improve the assessment of cancer location and extent within the prostate, extracapsular spread, and cancer aggressiveness. Additionally, pre- and post-therapy studies have demonstrated the potential of MRI/MRSI to provide a direct measure of the presence and spatial extent of prostate cancer after therapy, a measure of the time course of response, and information concerning the mechanism of therapeutic response. In addition to detecting metabolic biomarkers of disease behavior and therapeutic response, MRI/MRSI guidance can improve tissue selection for ex vivo analysis. High-resolution magic angle spinning ((1)H HR-MAS) spectroscopy provides a full chemical analysis of MRI/MRSI-targeted tissues prior to pathologic and immunohistochemical analyses of the same tissue. Preliminary (1)H HR-MAS spectroscopy studies have already identified unique spectral patterns for healthy glandular and stromal tissues and prostate cancer, determined the composition of the composite in vivo choline peak, and identified the polyamine spermine as a new metabolic marker of prostate cancer. The addition of imaging sequences that provide other functional information within the same exam (dynamic contrast uptake imaging and diffusion-weighted imaging) have also demonstrated the potential to further increase the accuracy of prostate cancer detection and characterization.

Cryosurgical ablation of the prostate: 5-year follow-up of a prospective study

OBJECTIVE

To study the complications and oncological outcome after cryosurgical ablation of the prostate (CSAP).

METHODS

Fifty-four patients with prostate cancer were entered into this prospective phase II trial of CSAP. Patients were followed with serum PSA determinations, follow-up biopsies at 3-6 months postoperatively and a questionnaire to assess complications. A PSA of >1 ng/ml or a positive biopsy was interpreted as progression.

RESULTS

Mean follow-up was 58.5 months. Patients needed a suprapubic catheter postoperatively for in mean 18 days. Transient penile numbness occurred in 15%. Bothersome sloughing of dead tissue was noticed by 15% of patients and 15% needed a transurethral resection. Nine patients (17%) developed strictures and five patients stone formation in the prostatic urethra. One patient developed a perennial fistula. Thirty-nine out of 43 patients reporting on potency become impotent, nine patients developed a slight stress incontinence and one severe incontinence.At median follow-up, the actuarial progression-free survival was 38.9%. Fourteen out of 50 patients biopsied (28%) had remaining cancer in their prostates.

CONCLUSION

High complication rates in combination with poor oncological outcome has made us stop using this treatment modality.

Cryosurgery as primary treatment for localized prostate cancer: a community hospital experience

The technique and recent experience incorporating cryosurgery into our community practice for primary treatment of localized prostate cancer is described. Between December 2000 and December 2001, a total of 93 patients underwent targeted cryoablation for localized prostate cancer. Of the 93 patients, 18 had failed radiotherapy, and cryotherapy was used as salvage therapy. The remaining 75 patients underwent targeted cryoablation of the prostate as primary therapy. A single urologist using an argon-based cryoablation system performed the procedure. Cryoprobes and thermosensors were placed under transrectal ultrasound guidance via a transperineal route. A double freeze-thaw cycle was used with anterior-to- posterior probe operation. Strategically placed thermosensors were used to monitor and control the freezing, and a warming catheter was used to protect the urethra. We achieved a nadir prostate-specific antigen level of < or =0.4 ng/mL in 84% of the entire population we studied (63 of 75 patients). Postsurgery complications were minimal. Incontinence developed in 4 patients, as did postsuprapubic catheter removal urinary retention. Erectile dysfunction developed in 28 of 34 patients who were potent preoperatively, with 6 of the 34 patients regaining potency after surgery. No rectourethral fistula formation occurred. Urethral sloughing was observed in 5 patients, 1 of whom developed a scrotal abscess during treatment of the sloughing. The use of cryoablation of the prostate for the treatment of localized adenocarcinoma of the prostate is feasible and can easily be transferred from the pioneering centers to the community hospitals without sacrificing safety or efficacy.

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

OBJECTIVES

To describe a new surgical approach to third-generation cryoablation of the prostate and present our preliminary results.

METHODS

The technique is detailed and demonstrated in a Web-based video- clip tutorial. Ninety-two men underwent prostate cryoablation (71 primary ablations, 19 salvage procedures, and 2 repeated cryoablations), using direct transperineal placement of ultrathin probes through a 17-gauge brachytherapy template.

RESULTS

No fistulous or major complications were observed. Eight patients (8.3%) had minor complications. In 36 patients, the follow-up period was long enough to permit nadir prostate-specific antigen (PSA) evaluation. In 31 (86%), the nadir PSA was 0.5 ng/mL or less. In 5 patients, the nadir PSA was greater than 0.5 ng/mL. The workup revealed systemic failure in 3 patients and inadequate eradication of the prostate gland in 2 patients. In 18 (86%) of 21 androgen-ablation-naive patients, the nadir PSA was 0.5 ng/mL or less. Nine (43%) had an undetectable nadir PSA and 3 had a nadir PSA of greater than 0.5 ng/mL.

CONCLUSIONS

A modified, less-invasive approach to cryoablation of the prostate is presented. The preliminary results do not show an increased rate of complications compared with other published series. The clinical outcome data are preliminary. Longer follow-up data are required to draw conclusions concerning efficacy.

Treatment of prostate cancer: watchful waiting, radical prostatectomy, and cryoablation

Current advances in diagnostic modalities and screening has lead to diagnosis of prostate cancer at an earlier stage (the so-called "stage shift" phenomenon), making primary treatments of localized disease of extreme importance in management. Therapeutic modalities include conservative management, radical prostatectomy, external beam radiotherapy, and newer techniques such as cryoablation surgery and brachytherapy. This review will focus on the non-radiation, non-hormonal primary treatment of localized prostate cancer and discuss the popularity and success of "watchful waiting," radical surgery, and cryoablation along with their advantages and disadvantages. These treatments will be compared to the qualities of an ideal treatment, which include cost effectiveness, efficacy, convenience of administration, tolerance by patients, low morbidity and mortality, and minimal impact on quality of life.

New indications for radical prostatectomy

PURPOSE

Radical prostatectomy is considered the gold standard for treatment of localized prostate cancer, either as primary or salvage therapy. Recently with the advent of increased organ transplantation, use of prostatic specific antigen for cancer detection and cryoablation as an alternative treatment, more men with prostate cancer can be considered for radical surgery. We review these new indications.

MATERIALS AND METHODS

Clinically localized untreated prostate cancers were identified in 3 men being considered for cardiac or lung transplantation (group 1), and 4 men originally treated with transperineal cryoablation had local relapse (group 2). All 7 men underwent radical prostatectomy.

RESULTS

Organ confined cancer (pT2C) was found in all 3 patients in group 1. All 3 men underwent successful cardiac or lung transplantation 1 to 12 months after radical prostatectomy, and they are disease-free at short-term followup. Of the group 2 patients 2 had organ confined disease (pT2b and c) and 2 had extensive extraprostatic disease (pT3cN1 and pT3cN0). Only 2 patients remain disease-free and do not require adjuvant endocrine therapy. Major perioperative complications of rectotomy and total incontinence occurred only in group 2 patients.

CONCLUSIONS

Patients being considered for heart and lung transplantation need to be free of concurrent malignancy because of immunosuppressive therapy. Radical prostatectomy can achieve this goal in select patients. Cases of failed cryoablation can be salvaged with radical prostatectomy but with less chance of success and with greater risk of complications.

In vivo results with a new device for ultrasonic monitoring of pig skin cryosurgery: the echographic cryoprobe

One of the main difficulties encountered in cryosurgery is the uncertainty in the extent and depth of the tissue effectively treated during the freezing process. The objective of this study was to evaluate in vivo ultrasonic control of skin cryosurgery using a new echographic cryoprobe. An echographic cryoprobe, developed specifically for dermatology applications, combines a high-frequency (20 MHz) miniature ultrasonic transducer and a N2O-driven closed cryoprobe. Knowledge of the ultrasound velocity of frozen skin is a prerequisite for monitoring the iceball formation kinetics. Therefore, in a first study, we estimated the ultrasound velocity of frozen skin specimens. In a second step, the operation of the echographic cryoprobe was assessed, under in vivo conditions similar to those used in human therapeutics, on normal skin of three female "Large-White" pigs under anesthesia. The mean value of ultrasound velocity of frozen skin obtained by pooling the data from all the skin specimens included in this study was 2865 +/- 170 m per s. The average rates of growth (10(-2) mm per s) of the iceballs were found to be 12.2 +/- 1.0 (pig 1), 9.0 +/- 1.0 (pig 2), and 8.4 +/- 0.9 (pig 3). The echographic cryoprobe had a built-in high-frequency ultrasonic transducer that served two functions. It enabled in vivo real-time monitoring of depth penetration of the iceball and it gave important feedback to the operator or to the console relating to the rate of growth of the iceball. Automatic (i.e., operator-independent) detection of the echo signal from the freezing front and calculation of the depth penetration of the iceball was possible.

Open-configuration MR imaging, intervention, and surgery of the urinary tract

The open-configuration MR imaging system provides new applications both in diagnosis and in therapy of conditions in the urinary tract. In addition to conventional imaging, the open configuration permits MR imaging of patients in many positions. This has already been shown to be useful in imaging the pelvis during voiding, where a sitting position allows urodynamic evaluation. The lithotomy position can be used for imaging the prostate, which also permits procedural access. The ultimate purpose of the interventional MR imaging suite is to integrate therapeutic tools and techniques with MR imaging. From surgical planning through specialized imaging systems with minimally invasive surgical applications, new methods are being developed and implemented. This new field of image-guided therapy will require extensive clinical development and evaluation for applications in the urinary tract. This will require a large concentrated interdisciplinary effort of surgeons, radiologists, computer scientists, engineers, and physicists. Successful integration of basic research and clinical work will result in a number of cutting-edge technologies with direct clinical application in the urinary tract. Initial projects have included biopsies, endoscopies, and real-time procedural control of high-temperature and cryogenic ablations. It is anticipated that the current surge in image-guided interventions will motivate even more research activity in this field, and will ultimately define the role of MR imaging guidance in urologic intervention and surgery.

Percutaneous transperineal radiofrequency ablation of prostate tumour: safety, feasibility and pathological effects on human prostate cancer

OBJECTIVE

To evaluate the safety of radiofrequency (RF) energy delivered interstitially in patients with prostate cancer scheduled for radical prostatectomy and to correlate the proposed theoretical lesion size with the pathological findings.

PATIENTS AND METHODS

Radiofrequency interstitial tumour ablation (RITA) was performed in 15 patients with localized prostate cancer before radical surgery. RF energy was delivered to the prostate by active needle electrodes (monopolar or bipolar) placed transperineally under transrectal ultrasonography guidance. Needle electrodes were used with different configurations and in some cases were covered by retractable shields to vary the length and circumference of the thermal lesions created. In eight patients, the procedure was performed immediately before radical prostatectomy, in six RITA was performed under spinal anaesthesia 1 week before surgery and in one patient, no surgery was performed but the patient was followed by serial determinations of prostate specific antigen (PSA). At least two lesions were created in each prostate, including both capsule and peripheral zones. NADPH and haematoxylin & eosin (H&E) staining were used to assess the extent of the necrotic lesion in the radical prostatectomy specimen.

RESULTS

The mean energy delivered was 10.5 kJ, with central temperatures reaching up to 105 degrees C during 12 min of ablation; rectal temperature remained at < 38 degrees C. There were no complications. Macroscopic examination showed well-demarcated lesions including the prostatic capsule, up to 2.2 x 1.5 x 4.5 cm. With monopolar energy, the observed lesion size was comparable to the predicted 2 x 2 x 2 cm lesion, while with bipolar energy, lesion size was related to interneedle distance and uncovered needle length. Microscopic examination showed clearly delineated lesions both with NADPH (in prostates immediately removed after surgery) and H&E (at 1 week after RITA) staining. The lesion size observed on pathological analysis correlated with the predicted lesion size. In one patient, no residual cancer was found in the specimen. In the patient whose entire prostate was targeted and followed by serial PSA measurements, the latter were undetectable at 3 months of follow-up.

CONCLUSION

Transperineally delivered RF energy is capable of safely creating extensive coagulative necrotic lesions in prostate cancer tissue, in a reproducible and controlled manner. The results presented here provide basic information for the potential future application of this form of energy for localized prostate cancer.

Preliminary outcomes following cryosurgical ablation of the prostate in patients with clinically localized prostate carcinoma

PURPOSE

Cryosurgical ablation of the prostate is a novel therapeutic modality that induces cell lysis in the prostate by direct application of low temperatures. We have been conducting an ongoing prospective pilot study of the use of cryosurgical prostate ablation in treating patients with nonmetastatic prostate adenocarcinoma since January 1993. Results in 145 consecutive patients with mean 36 months and minimum 12 months of followup are presented.

MATERIALS AND METHODS

Accrual was open to patients with clinical stages T1a to T3c prostate adenocarcinoma. Pelvic lymph node dissections were recommended but not required for patients with prostate specific antigen (PSA) greater than 15 ng./ml. before study entry. PSA changes, random prostate biopsy findings and morbidities after cryosurgical prostate ablation were recorded for each patient.

RESULTS

Overall actuarial rates at 42 months for maintaining PSA less than 0.3 and less than 1.0 were 59% and 66%, respectively. The overall actuarial progression-free rate at 60 months was 56%. Among 160 biopsies performed 16% showed some evidence of residual carcinoma. Overall crude rates of maintaining either a negative biopsy or PSA less than 0.3 at 6 and 24 months after cryosurgical prostate ablation were 87% and 73%, respectively. Significantly higher morbidities were seen in previously radiated patients undergoing cryosurgical prostate ablation compared to those with no prior radiation. Among nonradiated patients 85% experienced no significant morbidity after cryosurgical prostate ablation.

CONCLUSIONS

Although preliminary, short-term outcomes after cryosurgical prostate ablation appear to be comparable to identical outcomes reported for external beam radiotherapy. Based on these results cryosurgical prostate ablation appears to be an effective therapeutic alternative for treating patients with localized prostate adenocarcinoma.

Cryosurgical ablation of prostate cancer: patterns of cancer recurrence

PURPOSE

We determined the rate of biochemical and biopsy failure in relation to the prostate specific antigen (PSA) nadir, the effect of neoadjuvant androgen blockade and the pattern of residual tumor after cryosurgical ablation of prostate cancer.

MATERIALS AND METHODS

From July 1993 to April 1996, 134 patients underwent 147 cryosurgical ablation procedures. Of those patients, 110 had adequate followup and did not receive post-treatment androgen deprivation. Followup included PSA determination at 3, 6 and 12 months, and every 6 months thereafter. Biopsies were performed at 6 months or with biochemical failure defined as PSA nadir 0.5 ng./ml. or greater or subsequent biochemical failure (PSA increase 0.2 ng./ml. or greater). Biochemical and biopsy failures were correlated with PSA nadir values following cryosurgery (less than 0.1 ng./ml., 0.1 to 0.4 and or greater 0.5). A total of 68 patients had careful ultrasound guided mapping biopsy preoperatively and postoperatively to define the sites of disease. The likelihood of residual disease was correlated with the initial site(s) of the cancer in an attempt to identify if areas of the prostate and/or seminal vesicles were more likely to be sites of treatment failure.

RESULTS

At a mean followup of 17.6 months biochemical failure (subsequent rise in PSA 0.2 ng./ml. or greater) was lowest in those who achieved PSA nadirs less than 0.1 ng./ml. (21%) but it was noted in 48% of patients with nadirs between 0.1 and 0.4 ng./ml. Those patients with PSA nadirs 0.5 or greater had either immediate local failure (46%), subsequent local or biochemical failures (43%) or extremely high PSA nadirs (greater than 30 ng./ml.) necessitating hormonal therapy (11%). Biopsy failure was lowest in those with nadirs less than 0.1 ng./ml. (7%) and those with nadirs 0.1 to 0.4 ng./ml. (22%). In contrast, 60% of the patients with nadir values 0.5 ng./ml. or greater had biopsy failure. Biochemical and biopsy failure tended to occur within the first 18 months after treatment. Neoadjuvant androgen blockade appeared to reduce subsequent biochemical failure in patients with stages T1 and T2 cancers (11% versus 50% in those without androgen deprivation) but not in those with T3 and T4 cancers. Recurrence was more common in cancers at the apex (9.5%) and seminal vesicles (44%), in contrast to those located in the mid gland (4%) and base (0%).

CONCLUSIONS

A PSA nadir of 0.4 ng./ml. or less should be achieved following cryotherapy. Higher values are associated with a significant risk of continued PSA elevation and a high likelihood of residual disease detected on prostatic biopsy. Local failure tends to occur at the apex and seminal vesicles. Neoadjuvant androgen blockade reduces the risk of biochemical failure in patients with stages T1 and T2 cancers.

Bile duct warmer in hepatic cryosurgery--a pig liver model

Freezing of the common bile duct resulted in injury, stenosis, or perforation of the bile duct in a dog model. Biliary cutaneous fistulas and bile leaks are reported as complications of hepatic cryosurgery in man. In an ex vivo pig liver model we compared freezing close to the bile duct with and without warming the bile duct with warmed saline solution via an inserted catheter ("bile duct warmer"). The recorded temperatures at the outer wall of the bile duct were -50 degrees C after 10 min of freezing without and 5. 8 degrees C with the use of the warmer (P < 0.001, two-way ANOVA). The bile duct warmer system may be a simple and inexpensive device in reducing perioperative morbidity after hepatic cryosurgery of hepatic liver lesions close to a bile duct.

Prostate-specific antigen after cryosurgical ablation of the prostate. Defining the appropriate response

The ability of prostate-specific antigen (PSA) to predict long-term cure after cryotherapy for localized prostate cancer is not known because experience with this treatment modality is limited; however, it appears that a PSA value of 0.5 ng/mL or less at 6 months or longer after cryotherapy is associated with a high probability of a negative post-treatment biopsy (greater than 95%). An undetectable PSA (less than 0.1 ng/mL) 3 months after the procedure is associated with a likelihood of a negative biopsy at 6 months and low, stable PSA levels up to 2 years.

Focal therapy for prostate cancer 1996: maximizing outcome

OBJECTIVES

To summarize improvements in patient selection and the results of focal therapy for the management of localized prostate cancer.

METHODS

A contemporary series of patients managed with wide surgical excision, radiation therapy (three-dimensional conformal radiation, interstitial radiation, and charged-particle or proton therapy), and cryo-therapy were reviewed.

RESULTS

We used preoperative cancer grade, transrectal ultrasound, and serum prostate-specific antigen (PSA) in all patients, and cross-sectional imaging and bone scans in selected patients to allow for reasonably accurate cancer staging and selection of patients most likely to be cured by radical prostatectomy or radiation. In patients with extracapsular extension of prostate cancer, wide surgical excision and achievement of a clear surgical margin had therapeutic value. Newer radiation techniques resulted in a higher likelihood of prostate cancer control than previous techniques. Cryotherapy for patients with stages T1 through 3 prostate cancer was associated with a posttreatment undetectable PSA rate of 48% and a positive biopsy rate of 23%.

CONCLUSIONS

Patients with organ-confined and, therefore, curable prostate cancer can be identified. Well-performed radical prostatectomy, radiation, and cryotherapy are alternative treatments for the management of localized prostate cancer.

Cryoablation for carcinoma of the prostate

Percutaneous transperineal cryoablation of the prostate is now available in the armamentarium for treatment of prostate cancer. Technical advances in real-time transrectal imaging of the prostate and improvements in cryosurgical equipment have brought this modality into the limelight of available prostate cancer management. Cryosurgery can be offered to many patients with prostate cancer. However, the main indications for its use include primary treatment for localized disease, salvage therapy after failure of traditional methods, and relief of local symptoms. A historical background, description of the technique, and clinical experience at several medical centers including the University of California San Diego, Allegheny General Hospital, University of Texas M.D. Anderson Cancer Center, and Crittenton Hospital, are presented.

Should cryosurgery be considered a therapeutic option in localized prostate cancer?

Cryosurgical ablation of the prostate currently is under investigation as a potential treatment for localized prostate cancer. Results to date indicate that the majority of patients have negative biopsies and a marked reduction in prostate-specific antigen levels following cryotherapy. This treatment, however, is associated with significant side effects, notably bladder outflow obstruction, impotence, and incontinence, and its long-term durability is still unknown.

Detection of locally recurrent prostate cancer after cryosurgery: evaluation by transrectal ultrasound, magnetic resonance imaging, and three-dimensional proton magnetic resonance spectroscopy

OBJECTIVES

To assess and compare the clinical usefulness of transrectal ultrasound (TRUS), magnetic resonance imaging (MRI), and three-dimensional proton magnetic resonance spectroscopic imaging (3-D MRSI) in detecting local recurrence of carcinoma of the prostate (CaP) in patients with detectable prostate-specific antigen (PSA) levels after cryosurgery.

METHODS

In a prospective study, 25 patients who had undergone cryosurgery as primary treatment for CaP underwent endorectal MRI and 3-D MRSI, followed by TRUS-guided prostate biopsy. At the time of study, 20 patients had detectable PSA; the remaining 5 patients served as controls. All patients had random sextant and guided prostate biopsy for correlation with imaging and MR spectroscopic findings.

RESULTS

In patients with detectable PSA, MRSI identified, location-for-location, all foci of CaP and benign prostatic tissue that were detected by prostate biopsy. MRSI identified more sites with CaP than did prostate biopsy, indicating a larger volume of cancer. In 2 patients with detectable PSA and negative prostate biopsy, MRSI identified 11 voxels with viable prostatic tissue. In patients with undetectable PSA, both MRSI and prostate biopsy showed necrosis. Ultrasound and MRI were very poor tools for identifying recurrent cancer and differentiating between viable and necrotic prostate tissue.

CONCLUSIONS

3-D MRSI is superior to TRUS and MRI in differentiating among CaP, BPH, and necrosis when local recurrence after cryosurgery is suspected. By providing chemical mapping of the prostate in contiguous voxels, the addition of spectroscopy to endorectal MRI increases the sensitivity for detection of local recurrence.

Is there a role for cryoablation of the prostate in the management of localized prostate carcinoma?

It is impossible to adequately answer the question of whether there is a role for CSAP in the management of localized prostate carcinoma without considering the relative advantages and limitations of using other therapies to manage this disease (radical prostatectomy, radiation therapy, hormonal therapy, brachytherapy, expectant observation, and so on). Obviously, this is beyond the scope of this article. It is probably fair to point out, however, that the management of localized prostate carcinoma in the United States is generally quite controversial at the present time, and that despite a considerable amount of data pertaining to these therapeutic alternatives, it is difficult to discern a standard approach that can be broadly applied for all men with this disease. Therefore, if an absence of consensus on the management of localized prostate carcinoma does exist, it seems evident that investigations into alternative therapies are justified, and the preliminary results and efforts investigating CSAP fall well into this paradigm. In this context, several points can be made based on the available information. Significant numbers of patients who undergo CSAP can sustain undetectable levels of PSA for durable periods of time (more than 24 months). Thus, on a clinical level it seems possible to ablate the entire prostate with percutaneous CSAP, although rates of achieving this may be lower than originally anticipated. The reasons for persistence of carcinoma post CSAP are likely technical and related to the difficulties in determining the effective probe placements, number of probes to be used, number of freeze-thaw-freeze cycles to be used, and so on. Previous radiation exposure appears to confer an increased risk of CSAP-related morbidity, with incontinence, tissue sloughing, and rectal injury most prominent. Among nonradiated patients, incontinence is rare, and the most prominent postoperative concern involves BOO/tissue sloughing in a minority of patients. The longest follow-up data available on CSAP suggests that for patients with nonmetastatic prostate carcinoma, CSAP is associated with persistence of carcinoma in only 25% of patients. This compares favorably with the available biopsy data following external beam radiotherapy, in which most reports document positive biopsy results ranging between 30% and 100%, with the majority in the 40% to 50% range. Notably, the positive biopsy rate among patients with stage T3 disease following CSAP at 2 years can be less than 30%, which compares very favorably with previously reported positive biopsy result for these patients following external beam radiation therapy, which ranged between 40% and 100%. The management of patients with persistent carcinoma following CSAP poses fewer concerns to physicians than for those with persistent carcinoma following radiation therapy. Given the number of patients with prostate carcinoma who currently undergo radiotherapy as primary management, these data indicate that CSAP can now be considered a very viable therapeutic alternative for selected patients. With standardizations of technique as well as improved modifications in equipment, these preliminary CSAP results may well improve steadily in the near future. In the absence of randomized, comparative trials, it is difficult to draw meaningful comparisons between CSAP and radical prostatectomy. Based on available information, CSAP appears to be associated with a much lower incidence of stress and total incontinence than is radical prostatectomy. The rates of impotence following CSAP are somewhat comparable to those seen after radical prostatectomy, with wide variation among individual series. For patients who would be ideal candidates for radical prostatectomy (for example, less than stage T2c disease, PSA less than 10 ng/mL, and Gleason score of 7 or less), several authors have noted that the positive biopsy rate between 6 and 12 months is less than 10%.