What is cryosurgical ablation?

Cryosurgical ablation or cryotherapy is a minimally invasive procedure that uses very precise freezing and thawing technology to destroy prostate cancer cells. The damage caused by freezing cells is scientifically evident at molecular, cellular and whole tissue levels. Important factors which influence the procedure are the rate of temperature reduction after the initiation of freezing, the time the cells remain frozen and the subsequent rate of heating during thawing. The concept of cryotherapy was used as far back as 2500 B.C. when Egyptians applied cold water to relieve pain. Today, modern cryotherapy has experienced great advances, especially during the past decade with the introduction of accurate imaging using ultrasound, controllable freezing using Argon gas and reduced complications using ultra-thin cryoablation needles (size of the biopsy needle).

Who are the most suitable candidates for cryoablation of the prostate?

We offer a range of minimally invasive options for patients with clinically localized prostate cancer. The best candidates for this procedure are often those who are reluctant to undergo minimally invasive surgery e.g. robotic assisted laparoscopic prostatectomy because of their age, health status, or previous extensive abdominal surgery or radiation. While highly effective at cancer control, cryosurgical ablation of the prostate often freezes the erectile nerves in addition to the cancer, leading to erectile dysfunction after surgery. Thus, patients already suffering from erectile dysfunction are among the best candidates for this procedure. Additionally, patients who have experienced recurrent prostate cancer following radiation therapy can be treated effectively and with a low risk of complications with cryosurgical ablation of the prostate.

How is the procedure performed?

Dr Slawin at the da Vinci console

Fig. 1 The prostate is imaged throughout the procedure using transrectal ultrasonography. The white dense "dots" on the image are images of the needles spaced throughout the prostate

After the freezing cycle is complete, the physician begins to thaw the ice. The freeze-thaw cycle is repeated twice, to ensure complete killing of the cancer cells.

What can be expected after treatment?

Patients are usually discharged the same day, although some patients may remain overnight. Patients usually wear a catheter for about one week after the procedure. Oral antibiotics are usually given for 10 to 14 days. Occasionally, patients may experience different symptoms and signs including generalized fatigue for a few days, urethral discharge, scrotal swelling, numbness at the tip of the penis, passage of flecks of tissue, pain or burning sensation during urination and increased urinary frequency and/or urgency, however these are all generally mild in nature. Follow-up appointments for the catheter removal and then beginning six weeks after the procedure, will be scheduled to monitor the effectiveness of the procedure and the recovery from the procedure.

A PSA test is usually done at this first six week visit and then every three months afterwards for monitoring. A biopsy of the prostate may be done at some point after the treatment to determine whether any residual cancer cells are present in the prostate. especially if the PSA level is rising. If the biopsy proves negative, PSA measurements will be periodically obtained typically every six months thereafter.

What type of results can be expected?

During the past few years many U.S. institutions and physicians have reported their experience with the use of cryoablation (See abbreviated list below). Reported results indicated that less than 1% of patients experience incontinence following cryotherapy. Since the nerve bundles are adjacent to the prostate gland, most patients will be impotent especially if the entire prostate was frozen. The outcome and follow-up indicate up to 47% of patient may regain erectile function over time (depending on their age and general health condition). Additionally, qualified patients may be candidates for nerve-sparing cryotherapy (focal ablation) a recent procedure modification which seems to preserve potency in up to 80% of the patients selected for treatment.

Patients are classified as low risk, moderate risk or high risk according to the cancer characteristics (stage of the disease, Gleason grade and PSA level). Today, seven to ten year data is available from various institutions which have monitored non-rising postoperative PSA levels. These levels have been categorized for low and medium risk patients with results ranging between 60 and 80 percent and for high-risk patients the results were between 30 - 40 percent. Approximately 15 - 18 percent of the patients were found to have a positive biopsy following the procedure. These results are encouraging and seem to place cryoablation therapy similar to radical prostatectomy and radiotherapy in effectiveness.

What are the risks associated with this procedure?

Modern cryotherapy combined with the technological advances of improved ultrasound imaging, precisely controlled freezing using Argon gas, temperature monitoring, template grids for needle placement and ultra-thin needles have resulted in a significant reduction in the rate of complications. However, some risks still exist. Perhaps one of the most critical is the risk of urinary rectal fistula, which creates a channel between the prostate or the bladder and the rectum and may cause diarrhea due to urine in the rectum and possibly severe infection due to bacteria in the bladder. Other complications, although uncommon given technological advances, include urinary incontinence, urinary retention requiring transurethral resection of the prostate (TURP) and inflammation of the testicle. Almost all patients have a temporary need for a catheter to empty the bladder for approximately one week. Permanent, severe incontinence is rare (approximately 1 percent) and other rare complications may include prostatic abscess and permanent penile numbness.

Additional "Frequently Asked Questions (FAQ)":

Is cryotherapy ever used after other prostate cancer treatments have been tried?

Yes. An important and effective use of cryotherapy is for those patients who fail or develop recurrence after radiation therapy treatment.

Am I a candidate for cryosurgical ablation?

When considering treatment options for prostate cancer, do your homework. Educate yourself on all of the different treatments. Whether you are being treated for the first time or you have experience recurrent prostate cancer, cryotherapy may be a viable option for you. Cryotherapy can treat the different risk groups with localized prostate cancer, meaning that the cancer has not spread beyond the prostate. It is important that you talk to your doctor to determine what treatment is best for you.

What are the potential advantages of cryosurgical ablation?

Because cryotherapy is minimally invasive, you may experience fewer complications then with other treatments:

• Eligible patients have a choice of general or regional anesthesia
• Recovery may be faster and there can be lower risk of potential side effects and complications
• No major surgery is necessary, so many patients are back to their lives quicker
• Cryotherapy can be used as a salvage option, when other treatments have failed

What are the potential drawbacks of cryosurgical ablation?

The most notable drawback of cryotherapy is impotence. Because cryotherapy freezes tissue in and around the prostate, cells that are associated with erection may also be affected. However, there is a chance that potency will return after time, depending on a your potency prior to the procedure. Additional side effects may include moderate pelvic pain, blood in the urine, mild urinary urgency, scrotal swelling, incontinence or urethral scarring - most of which usually revolve themselves in a few weeks.

Data and References

Katz AE, Prepelica K, Masson P. Salvage Cryosurgical Ablation of the Prostate (TCAP) for Patients Failing Radiation: 10-Year Experience. American Urologic Association Anual Meeting, 2005.

Treating localized prostate cancer after failed radiation is a challenge due to first-line therapy complications and aggressive radioresistant tumors. We report observations from 157 patients treated with salvage cryoablation between October 1994 and July 2004 with follow-up ranging between 3 and 119 months (median 37 months). Mean and median PSA nadirs were 0.8 and 0.1 ng/mL with 131 patients (83.4%) reaching a nadir <1.0 ng/mL. Although radiation failure patients typically present with comorbidities, patients in this series enjoyed a relatively low rate of additional morbidities including incontinence (9.7%), voiding complications (5.8%), rectal pain (12.8%), and retention (1.9%). The 50 most recently treated patients had an 83.3% ASTRO bRFS and 6.4% incontinence rate.

This 10-year experience with salvage cryoablation for recurrent prostate cancer validates its safety and efficacy. TCAP remains a viable option in the treatment of patients who have biopsy-proven local failure after radiation therapy for prostate cancer with significantly less complications than radical surgery. (8) Walsh, J. Urology 2000, 163:1802-1807.

Onik G. The Male Lumpectomy: Rationale for a Cancer Targeted Approach for Prostate Cryoablation. A Review. Technol Cancer Res Treat. 2004 Aug;3(4): 365-70

Lumpectomy to treat breast cancer has revolutionized the management of that disease. Lumpectomy showed that the quality of life of the individual patient can successfully be integrated into the equation of cancer treatment, without major loss of cancer treatment efficacy. Prostate cancer raises many of the same issues that breast cancer does in women. Impotence and incontinence, affects the male self image and psyche no less than the loss of a breast does a woman. Management of prostate cancer ranges from no treatment at all ("watchful waiting") to treatments in which the whole gland is destroyed (radiation therapy, cryosurgery) or removed (radical prostatectomy), with presently no treatment in between these extremes. Pathologic literature indicates, however, that 35% of prostate cancers are solitary and unilateral. In addition, long term studies have confirmed that cryoabltion for prostate cancer is an efficacious treatment. In this paper we will examine the rationale for a "male lumpectomy" using cryoablation and present preliminary data supporting it's role in prostate cancer management.

Bahn DK, Lee F, Silverman P, Bahn E, et al. Salvage cryosurgery for recurrent prostate cancer after radiation therap: a seven-year follow-up. Clin Prostate Cancer. 2003;2(2):111-4

Cryosurgery of the prostate presents as an efficient therapy following failed radiation therapy. We report on a 7-year retrospective analysis evaluating the morbidity adn biochemical disease-free survival(bDFS) of this therapy. Between 1993 and 2001, 59 patients who had been previously treated with radiation therapy and had rising serum prostate-specific antigen(PSA) values underwent salvage cryoablation of the prostate for localized, histologically proven, recurrent prostate cancer. Serial serum PSA testing was performed, and biopsies were taken at 6, 12, and 24 months, and again at 5 years, and any time the PSA rose above 0.5 ng/mL. Patients were stratified along clinical parameters. The combined postsalvage bDFS rate using a PSA cutoff of 0.5 ng/mL was 59% and 69% with a 1.0 ng/mL PSA cut off. Using a PSA threshold of 0.5 ng/mL as evidence of biochemical recurrence, 61%, 62%, and 50% of patients with <4 ng/mL, 4-10 ng/mL, and > 10 ng/mL PSA, respectively, remain biochemically relapse free at 7 years. A threshold of 1.0 ng/mL yielded a disease-free status of 78%, 74%, and 46% respectively. Patients biopsies showed no evidence of residual or recurrent disease. Improved survival rates and no known latent complications indicate cryosurgery is a promising form of treatment for radiation-resistant prostate cancer. This 7-year analysis shows a promising validation of cryosurgery as an efficacious treatment modality for locally confined T1-T3 prostate cancer following primary radiation therapy failure.

Shinohara K. Prostate cancer: cryotherapy. Urol Clin North Am. 2003;30(4):725-36, viii. Review.

he incidence of prostate cancer has more than doubled in the last 10 years, and 220,900 new cases will be detected in 2003. This increase is due in large part to increased use of prostate-specific antigen (PSA)-based screening, transrectal ultrasonography, and random biopsy of the prostate. The treatment of prostate cancer, however, remains controversial, and no consensus has been established as to what constitutes appropriate treatment for any stage of disease, especially for localized cancers. Radical prostatectomy, radiation therapy, or watchful waiting all have their advocates, and the risks and benefits of these approaches are discussed frequently. Skepticism about conventional treatments has stimulated patients and physicians to search for alternatives that are effective and associated with limited morbidity. Technologic developments have rekindled interest in cryotherapy as a viable alternative to other, more conventional localized therapies. Given the relative paucity of alternatives for patients who experience biochemical progression after radiotherapy, cryosurgery also may prove to be a good alternative for those patients whose tumors appear to remain localized despite progression. In addition, it appears that cryosurgery will play an increased role in the future management of prostate cancer.

Johnson DB, Nakada SY. Cryoablation of renal and prostate tumors. J Endourol. 2003;17(8):627-32. Review.

During the past decade, cryoablation has been applied to benign and malignant conditions within the prostate and kidney. The essence of cryosurgery lies in producing temperatures low enough to cause necrosis in target tissues while avoiding lethal conditions in healthy peripheral tissues. It works by two main mechanisms: (1) at the cellular level via solute damage and intracellular ice formation; and (2) at the vascular level as a result of thrombosis and subsequent coagulative and ischemic necrosis. Investigation of cryoablation for renal tumors began in 1964, and by the 1990s, attention was turning to its use as a means of treating renal tumors. Modern renal cryosurgery is applied using minimally invasive techniques. Cryotherapy was first applied in the prostate in 1966 and soon thereafter was used to treat prostate cancer. Today, prostate cryosurgical techniques employ ultrasound monitoring and urethral warming to minimize urethral and rectal complications.