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Prostate Cancer: Cryoablation Treatment

Prostate cancer is one of the most common forms of cancer in men and some of its traditional treatments can result in serious complications. However, cryoablation is an emerging alternative therapy for prostate cancer that shows great promise. Due to recent advances with smaller needles and computer guided programs to insert the needles, the procedure has become much more effective and offers patients an outpatient treatment with minimal side effects. What does this new treatment entail? What are its advantages and disadvantages? The following information should help answer those questions and more.

What is cryoablation?
Cryoablation for prostate cancer involves the controlled freezing of the prostate gland in order to destroy cancerous cells. Cryoablation however is not cancer specific, and the treatment will ablate all of the epithelial cells that are in the targeted area. The damage caused by freezing occurs at several levels: molecular, cellular and whole tissue structure. In particular, cryotherapy kills targeted tissue by three modes of cell death: (1) cell trauma (secondary to intracellular ice formation), (2) necrosis (immediate cell death and also delayed death secondary to vascular stasis preventing oxygen to tissues), and (3) apoptosis (programmed cell death). In addition, there may be an immunological effect when the cancerous cells are killed. Important factors influencing freezing injury are the rate of temperature reduction after the initiation of freezing, the end-temperature reached and performing two freeze-thaw cycles.

The cells are not the only structures damaged during freezing. During cryoablation of the prostate, the surrounding connective tissue (stroma) and the smallest blood vessels (capillaries) are damaged and subsequently have an inadequate blood supply that is also believed to eradicate cancer.

Who are the most suitable candidates for cryoablation of the prostate?
Suitable candidates for this procedure are patients who have organ-confined prostate cancer or those who have minimal spreading beyond the prostate (clinical stage up to T3a). This includes patients undergoing prostate cancer treatment for the first time and those with recurrent cancer following radiation treatment (external beam or brachytherapy). One benefit of cryotherapy is that it is equally effective when ablating (removing) cancers of any Gleason grade. Due to the ability to use smaller needles, it may be possible to eradicate an area of the prostate that contains the cancer rather than treating the entire prostate gland. This new form of focal cryotherapy is emerging and may change the way that prostate cancer is treated in the future.

How is the procedure performed?
Under anesthesia (either general or spinal), an ultrasound probe is guided into the rectum. The prostate is imaged and its dimensions measured. An aiming grid software program is then activated and images of the prostate are projected on a screen. Under continuous monitoring with ultrasound imaging, cryoablation probes or needles are placed at predetermined sites within the prostate. Each of the commercially available cryosurgical systems has a different type of probe and placement strategy, but all aim to freeze the prostate, tumor(s) and surrounding tissue—except the urethral area. A urethral warming catheter keeps the urethra warm throughout the procedure and is kept active for about 20 minutes after the final thaw cycle to prevent the urethra from freezing. In addition to the freezing probes, small temperature probes are also placed in and around the gland to monitor the temperature of the rectal wall as well as other sites such as the urinary sphincter. This has led to a dramatic reduction in side effects such as urinary incontinence and rectal fistula formation.

Prior to the freezing process, cystoscopy (direct visual inspection of the bladder using a small telescope) is performed to ensure that cryoprobes have not inadvertently pierced the urethra; if so the probes are simply repositioned. A commercially available urethral warming catheter is placed at this time thereby protecting the urethra from freezing. This is important, as it minimizes the risk of urethral damage, obstruction and urinary incontinence.

Freezing starts at the anterior part of the prostate by activating the anterior probes, followed by the middle and finally the posterior probes. This sequence allows continuous monitoring (by visualizing the freezing process through the (trans-rectal ultrasound) and sculpting of the ice balls. The physician knows when to stop freezing using both the ultrasound image as a guide as well as monitoring the temperature probes. Two freezing cycles are usually done. Between them, the prostate is allowed to thaw either passively or actively by using helium or argon gas. If the prostate is longer than the active portion of the cryotherapy probe, an apical pullback maneuver is usually done to freeze the apex of the prostate. Double freezing is performed again. Following the final thaw, either a urethral Foley catheter or a suprapubic catheter (a small tube that is pierced into the bladder through a small opening in the lower abdomen) is inserted and secured in place. The physician will typically remove this catheter several days after cryotherapy when the patient is able to urinate. For most cases, the procedure can be performed under 2 hours.

What can be expected after treatment?
Cryoablation of the prostate is currently an outpatient procedure. The patient is usually discharged from the recovery room with either a urethral catheter or a suprapubic tube in place for drainage.

Prostate cryoablation will cause the prostate to swell in the short term. Once the swelling has resolved, typically in the order of several days to a few weeks after the procedure, the urinary catheter may be removed. The patient has to demonstrate that he is capable of urinating on his own, lest the catheter need to reinserted again until the prostate swelling has had sufficient time to resolve. If the patient is unable to urinate, the catheter is reinserted for a few more days. Most patients are able to urinate in about 5 to 15 days but some may require longer recovery periods. Oral antibiotics and other medications that help with urination or reduce catheter irritation may be given after treatment, depending on physician preference. Other less common side effects that the patient may experience are 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. Most men are pleasantly surprised that there is little to no pain after treatment, and recovery to normal health typically occurs within that first week. Of course, the most common symptoms that a man may experience are those related to having a catheter: urinary urgency and a minor amount of blood in the urine.

A PSA test is usually done at three months. Also, a prostatic biopsy may be recommended some time after the procedure to assess for prostate destruction and absence of viable cancer cells especially if PSA level continues to climb. Once the PSA level has stabilized, the PSA may be checked every 6 months or annually. Of course, if the PSA level is in a state of flux, it will likely be monitored more closely by your physician.

What type of results can be expected?
Currently there have been numerous publications on the use of cryoablation in the literature, both on the primary side as well as for salvage (those that have had prior radiation). One of the largest trials published compared the results of cryotherapy to those of conformal radiotherapy and brachytherapy. Patients with a previous history of failed radiotherapy were excluded and androgen deprivation was determined and categorized separately. Patients were classified as low risk, moderate risk or high risk according to the cancer characteristics (stage of the disease, Gleason grade and PSA level). The procedure was not consistent at all institutions. Differences included the number of probes used, number of freeze cycles per patient, length of apical pullback maneuver, real-time monitoring during freezing and the system used for freezing. A total of 975 patients were studied, of whom 238 were low risk, 321 were moderate risk and 385 were high risk; risk was not determined in 38 patients. The five-year rate for non-rising postoperative PSA levels for low and medium risk patients ranged between 60 and 76 percent and for high-risk patients it was 41 percent. Only about 18 percent of the patients were found to have a positive biopsy following the procedure. These results are encouraging and may place cryoablation therapy between radical prostatectomy and radiotherapy in effectiveness.

In addition, there are three peer-reviewed publications on the subject of focal cryotherapy. The number of patients studied is small, only 77 subjects combined. The average follow-up is also relatively short, 60 months, 70 months, and 28 months respectively. Various definitions of PSA or biochemical failure have been used to evaluate the clinical outcomes. These include the ASTRO (American Society for Therapeutic Radiology Oncology) definition that is three consecutive PSAs rising, the Phoenix definition that is the PSA nadir plus 2, and PSA nadir less than 50% of the pre-operative level. The biochemical disease free survival rates range from 84% - 95%. A biopsy was performed when biochemical failure was suspected, or as a protocol regardless of PSA levels. With every definition used, these three papers report fairly similar outcomes. A total of 71 of the 77 men had undergone post-cryotherapy biopsy with cancer identified in 4 patients (6 %). All except one of these residual cancers were seen in the untreated lobe.

Overall these are excellent results which indicate that prostate cryotherapy can result in high cure rates for men with early stage prostate cancer. This is really no surprise and somewhat expected. Since cryotherapy can cure recurrent high grade cancer that recurs after radiation, we would expect better results in the early stage, non radiated patient. The reason that this technology had not been used more frequently until fairly recently was because historically the imaging was not sophisticated enough to allow us to target or focus? On small cancers; there was no planning computer-guided software as there is today, and the cryotherapy needles that were available were just too big and bulky to perform a focal procedure with precision. As more follow-up studies are carried out and publications enter into the main stream journals, it is our strong belief that this form of therapy will continue to expand, as it should. We have seen this with breast cancer, where we are doing more lumpectomies than radical mastectomies, and we have seen this in kidney cancer, where the rise of partial kidney removals for renal cell cancer (partial nephrectomy) are becoming more common place and replacing the old total removal of the kidney. Minimally invasive treatment focusing on the cancerous lesion and sparing healthy normal tissue that is disease free has to be the way forward to reduce side effects of treatment and thus improve patient quality of life.

What are the risks associated with this procedure?
New technological advances have resulted in a significant reduction of the rate of complications. An improved FDA-approved urethral warming device has minimized urethral complications. Better spacing of the probes now contributes to the effectiveness and safety of the procedure. Improved monitoring of the freezing with real-time trans-rectal ultrasound and temperature thermistors has given the treating physician control over the size and shape of the ice balls formed. However, some risks still exist. Perhaps one of the most critical is the risk of urinary rectal fistula, which creates a channel between the urethra and the rectum and may cause diarrhea due to urine in the rectum and possibly severe infection due to bacteria in the bladder. However, this has largely been a complication using older technology and is rarely seen today. In fact, a recent study that included over 1000 patients in the COLD registry (Cryo On Line Database) revealed that the rectal fistula rate was only 0.4%. There is also a high incidence of erectile dysfunction when freezing the entire prostate. However, several physicians have developed methods to better preserve erections in those patients who are candidates for a nerve-preserving procedure. 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 several days after the procedure. Permanent, severe incontinence is rare (approximately 1 percent) and other rare complications include prostatic abscess and permanent penile numbness.

Frequently asked questions:

What are the advantages and disadvantages of cryoablation of the prostate?

Cryoablation therapy offers:

  • a minimally invasive, outpatient procedure
  • favorable success rate
  • low toxicity profile (complication rate)
  • high quality of life
  • a short recuperation period
  • No blood transfusions
  • Minimal anesthesia
  • can be effectively used for high grade cancers
  • the ice can be extended beyond the confines of the prostate to achieve an adequate margin
  • prostate cancer resistant to radiation, hormones or chemotherapy may be vulnerable to the physical trauma of ice
  • may be used as primary treatment or in those who have failed radiation treatment
  • procedure can be repeated if the first cryoablation has not completed killed the cancer
  • radiation therapy, radical prostatectomy, or hormonal therapy are still options if the procedure fails
  • less than half the cost of the traditional treatment

The disadvantages are:

  • extensive experience and training by the surgeon are required
  • long term outcomes using current technology are still needed

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

Yes. An important use of cryoablation therapy is for patients who fail or develop recurrence after radiation therapy (external beam or brachytherapy).

Where can I get more information?

Know Your Stats About Prostate Cancer Treatment Options: Cryosurgery

Reviewed January 2011

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Prostate Cancer: Cryoablation Treatment Glossary
  • abdomen: Also referred to as the belly. It is the part of the body that contains all of the internal structures between the chest and the pelvis.

  • ablation: Removal of diseased or unwanted tissue from the body by surgery or other means.

  • abscess: An accumulation of pus anywhere in the body.

  • androgen: Male sex hormone.

  • anesthesia: Loss of sensation in any part of the body induced by a numbing or paralyzing agent. Often used during surgery to put a person to sleep.

  • anterior: At or near the front.

  • antibiotic: Drug that kills bacteria or prevents them from multiplying.

  • apical: Used to describe the top of something.

  • bacteria: Single-celled microorganisms that can exist independently (free-living) or dependently upon another organism for life (parasite). They can cause infection and are usually treated with antibiotics.

  • biopsy: A procedure in which a tiny piece of a body part (tissue sample), such as the kidney or bladder, is removed (with a needle or during surgery) for examination under a microscope; to determine if cancer or other abnormal cells are present.

  • bladder: The bladder is a thick muscular balloon-shaped pouch in which urine is stored before being discharged through the urethra.

  • blood transfusion: The transfer of blood from a healthy donor into the bloodstream of somebody who has lost blood or has a blood disorder.

  • brachytherapy: Treatment for prostate cancer that involves the placement of tiny radioactive pellets into the prostate by utilizing ultrasound.

  • cancer: An abnormal growth that can invade nearby structures and spread to other parts of the body and may be a threat to life.

  • capillaries: Thin blood vessels.

  • catheter: A thin tube that is inserted through the urethra into the bladder to allow urine to drain or for performance of a procedure or test, such as insertion of a substance during a bladder X-ray.

  • cellular: Relating to small parts or groups.

  • chemotherapy: Treatment with medications that kill cancer cells or stop them from spreading.

  • continence: The ability to control the timing of urination or a bowel movement.

  • cryotherapy: During an operation, probes are placed in the prostate. The probes are frozen thus killing the prostatic cells.

  • cyst: An abnormal sac containing gas, fluid or a semisolid material. Cysts may form in kidneys or other parts of the body.

  • cystoscopy: Also known as cystourethroscopy. An examination with a narrow, flexible tube-like instrument passed through the urethra to examine the bladder and urinary tract for structural abnormalities or obstructions, such as tumors or stones.

  • epithelial cells: Closely packed layers of cells such as those in glands like the prostate.

  • erectile: Capable of filling with blood under pressure, swelling and becoming stiff.

  • erectile dysfunction: Also known as ED or impotence. The inability to get or maintain an erection for satisfactory sexual intercourse. Also called impotence.

  • erectile dysfunction: The inability to get or maintain an erection for satisfactory sexual intercourse. Also called impotence.

  • erection: Enlargement and hardening of the penis caused by increased blood flow into the penis and decreased blood flow out of it as a result of sexual excitement.

  • erection: Enlargement and hardening of the penis caused by increased blood flow into the penis and decreased blood flow out of it as a result of sexual excitement.

  • FDA: Food and Drug Administration.

  • fistula: An abnormal opening between two organs (between the bladder and vagina in women or the bladder and the rectum in men).

  • frequency: The need to urinate more often than is normal.

  • gas: Material that results from: swallowed air, air produced from certain foods or that is created when bacteria in the colon break down waste material. Gas that is released from the rectum is called flatulence.

  • gene: The basic unit capable of transmitting characteristics from one generation to the next.

  • gland: A mass of cells or an organ that removes substances from the bloodstream and excretes them or secretes them back into the blood with a specific physiological purpose.

  • hormonal therapy: Treatments that add, block or remove hormones.

  • hormone: A natural chemical produced in one part of the body and released into the blood to trigger or regulate particular functions of the body. Antidiuretic hormone tells the kidneys to slow down urine production.

  • immunologic: Relates to the immune system.

  • incontinence: Loss of bladder or bowel control; the accidental loss of urine or feces.

  • infection: A condition resulting from the presence of bacteria or other microorganisms.

  • inflammation: Swelling, redness, heat and/or pain produced in the area of the body as a result of irritation, injury or infection.

  • invasive: Having or showing a tendency to spread from the point of origin to adjacent tissue, as some cancers do. Involving cutting or puncturing the skin or inserting instruments into the body.

  • invasive: Not just on the surface; with regard to bladder cancer, a tumor that has grown into the bladder wall.

  • ions: Electrically charged atoms.

  • kidney: One of two bean-shaped organs that filter wastes from the blood and discharge these waste products in urine. The kidneys are located on either side at the level of the 12th ribs toward the back. The kidneys send urine to the bladder through tubes called ureters.

  • kidney cancer: The most common type of urologic cancer. The kidneys are two large organs that sit in the back part of the abdominal cavity. The kidney's main function is to filter the blood and clean the body of excess water, salt, and waste products. Tumors of the kidney occur twice as often in men as in women and usually occur between the ages of 50 and 70.

  • lesion: A zone of tissue with impaired function as a result of damage by disease or wounding. Examples are scars, abscesses, tumors and ulcers.

  • necrosis: Death of one more more cells, or a portion of a tissue or organ.

  • nephrectomy: Surgical removal of a kidney.

  • obstruction: something that obstructs, blocks, or closes up with an obstacle

  • partial nephrectomy: Surgery to remove the part of the kidney that contains a tumor.

  • penis: The male organ used for urination and sex.

  • posterior: Situated at the rear or behind something.

  • postoperative: Occurring after a surgical operation.

  • probe: Small device for measuring and testing.

  • prostate: A walnut-shaped gland in men that surrounds the urethra at the neck of the bladder. The prostate supplies fluid that goes into semen.

  • prostatectomy: Surgical procedure for the partial or complete removal of the prostate.

  • prostatic: Pertaining to the prostate.

  • PSA: Also referred to as prostate-specific antigen. A protein made only by the prostate gland. High levels of PSA in the blood may be a sign of prostate cancer.

  • PSA test: Also referred to as prostate-specific antigen test. A blood test used to help detect prostate cancer.

  • radiation: Also referred to as radiotherapy. X-rays or radioactive substances used in treatment of cancer.

  • radiation therapy: Also referred to as radiotherapy or radiation. X-rays or radioactive substances used in treatment of cancer.

  • radical: Complete removal.

  • radical prostatectomy: Surgical removal of the prostate and seminal vesicles.

  • radiotherapy: Also referred to as radiation therapy. High-energy rays are often used to damage cancer cells and stop them from growing and dividing.

  • rectal: Relating to, involving or in the rectum.

  • rectal ultrasound: A diagnostic test that uses very high frequency sound waves to produce an image of the rectum.

  • rectum: The lower part of the large intestine, ending in the anal opening.

  • renal: Pertaining to the kidneys.

  • resection: The surgical removal of a portion of a body part.

  • retention: In ability to empty urine from the bladder, which can be caused by atonic bladder or obstruction of the urethra.

  • scrotal: Relating to the scrotum, the sac of tissue that hangs below the penis and contains the testicles.

  • scrotal: Relating to the scrotum, the sac of tissue that hangs below the penis and contains the testicles.

  • sphincter: A round muscle that opens and closes to let fluid or other matter pass into or out of an organ. Sphincter muscles keep the bladder closed until it is time to urinate.

  • stage: Classification of the progress of a disease.

  • stent: With regard to treating ureteral stones, a tube inserted through the urethra and bladder and into the ureter. Stents are used to aid treatment in various ways, such as preventing stone fragments from blocking the flow of urine.

  • stroma: The connective tissue that provides the framework of an organ or other anatomical structure rather than carrying out its function.

  • suprapubic: An area of the central lower abdomen above the bony pelvis and overlying the bladder.

  • testicle: Also known as testis. Either of the paired, egg-shaped glands contained in a pouch (scrotum) below the penis. They produce sperm and the male hormone testosterone.

  • tissue: Group of cells in an organism that are similar in form and function.

  • toxicity: Degree to which something is poisonous.

  • transfusion: Transfer of whole blood, blood components or bone marrow from a healthy donor into the bloodstream of somebody who has lost blood or who has a blood disorder.

  • transurethral: Through the urethra. Several transurethral procedures are used for treatment of BPH. (See TUIP, TUMT, TUNA or TURP.)

  • transurethral resection: Surgery performed with a special instrument inserted through the urethra.

  • transurethral resection of the prostate: Also referred to as TURP. Surgical procedure where a lighted tube with an attached electrical loop is inserted through the urethra into the prostate. Serves as a diagnostic and therapeutic role in the treatment of bladder cancer.

  • tumor: An abnormal mass of tissue or growth of cells.

  • TURP: Also referred to as transurethral resection of the prostate. Surgical procedure where a lighted tube with an attached electrical loop is inserted through the urethra into the prostate. Serves as a diagnostic and therapeutic role in the treatment of bladder cancer.

  • ultrasound: Also referred to as a sonogram. A technique that bounces painless sound waves off organs to create an image of their structure to detect abnormalities.

  • urethra: A tube that carries urine from the bladder to the outside of the body. In males, the urethra serves as the channel through which semen is ejaculated and it extends from the bladder to the tip of the penis. In females, the urethra is much shorter than in males.

  • urethral: Relating to the urethra, the tube tha carries urine from the bladder to outside the body.

  • urge: Strong desire to urinate.

  • urgency: Strong desire to urinate.

  • urinary: Relating to urine.

  • urinary frequency: Urination eight or more times a day.

  • urinary incontinence: Inability to control urination.

  • urinary incontinence: Involuntary loss of urine associated with a sudden strong urge to urinate.

  • urinary retention: Failure to empty the bladder totally.

  • urinary urgency: Inability to delay urination.

  • urinate: To release urine from the bladder to the outside. Also referred to as void.

  • urination: The passing of urine.

  • urine: Liquid waste product filtered from the blood by the kidneys, stored in the bladder and expelled from the body through the urethra by the act of urinating (voiding). About 96 percent of which is water and the rest waste products.

  • urology: Branch of medicine concerned with the urinary tract in males and females and with the genital tract and reproductive system of males.

  • vas: Also referred to as vas deferens. The cordlike structure that carries sperm from the testicle to the urethra.

  • vascular: Having to do with blood vessels.

Prostate Cancer: Cryoablation Treatment Anatomical Drawings

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