Adult and Pediatric Urology
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video courtesy of Endocare, Inc
Cryoablation is a treatment for prostate cancer that uses small probes, called cryoprobes, inserted into the prostate gland in order to destroy the prostate cancer. The probes are placed precisely into the prostate using ultrasound guidance, and temperature sensors placed into and around the prostate are used to be certain that proper freezing of the tissue is obtained. The entire prostate is frozen to -40ºC, while the urethra is protected by a special warming catheter. The procedure is performed under spinal anesthesia, so the patient has no pain during the procedure.
ultrasound guidance for cryosurgery
Suitable candidates for this procedure are patients who have organ-confined prostate cancer or those who have minimal spreading beyond the prostate.
Prostate cryotherapy is performed with the patient under general or spinal anesthesia. A prostate ultrasound probe is placed in the rectum and the prostate measured. Under continuous monitoring with ultrasound imaging, cryoablation probes are placed at predetermined sites within the prostate. Temperature sensors are placed at each neurovascular bundle and at several other points to accurately measure prostate temperatures. A urethral warming catheter is placed to protect the urethra from being injured during the freezing. The freezing starts at the front part of the prostate by activating the front probes, followed by the middle and finally the back probes. The exact extent of the iceball is visualized clearly on ultrasound, so that the urologist freezing to extend to the limits of the prostate without injuring the rectum. Two freezing cycles are usually done, and the prostate is allowed to thaw either passively or actively between the freezing cycles. A suprapubic catheter (a small catheter that is pierced into the bladder through a small opening in the lower abdomen) is inserted and secured in place.
cryosurgery of the prostate
In most cases of cryosurgery the entire prostate is frozen, but two new variations of cryosurgery are possible for patients with smaller amount of cancer. Nerve-sparing cryosurgery uses a warming device to preserve the nerve that causes erections on the side of the prostate opposite the cancer. Both sides of the prostateare frozen, but one of the nerves is spared, which increases the chance that a man can preserve sexual function. Men with slow-growing cancer confined to one side of the prostate can be treated on one side only, a procedure called focal cryosurgery. This also may lower the risk of impotence after the procedure. Extensive biopsies of the prostate are required prior to one of the limited types of cryosurgery, so that you doctor can be certain that he knows exactly how much cancer is present in the prostate.
The patient is usually sent home the day of the procedure, but some patients may be kept overnight if they have pain or other reasons to stay in the hospital.The patient is sent home with a suprapubic catheter in place for drainage which connects to a drainage bag worn on the leg under the pants.
Patients usually leave the tube to drainage for the first week after the procedure, and then start to try to urinate when they feel the urge. Most patients are able to urinate in about 10 to 15 days but some may require longer recovery periods. When the patient is able to urinate well and empty the bladder satisfactorily, the suprapubic catheter is removed. Some surgeons use a urethral catheter instead of the suprapubic catheter. In that case, the urethral catheter is removed seven to ten days after treatment and a voiding trial is attempted. If the patient is unable to urinate, the catheter is reinserted for a few more days. Oral antibiotics are usually given for 10 to 14 days. Other symptoms and signs the patient may experience are generalized fatigue that usually persists for seven to 10 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.
A PSA test is usually done at three months. Also, a prostate biopsy may be done at three to six months to assess for prostate destruction and absence of viable cancer cells, especially if PSA level is detectable. If the biopsy proves negative, PSA measurements are obtained every 3 months for one to two years, then every six months for the next one to three years and every year thereafter.
Prostate cryosurgery has been performed on thousands of men by hundreds of doctors nationwide. Over 350 published studies help document the clinical value of cryoablation as a treatment of prostate cancer. Recent studies show 10 year cure rates as high as 90% for low risk patients, which is the same as the results of surgery or radiation treatments. Patients found to have persistant cancer in the prostate after cryosurgery can undergo repeat treatment, or can have surgery to remove the prostate or radiation treatments.
New technological advances have resulted in a significant reduction of the rate of complications. Improved urethral warming devices have minimized urethral complications. Better spacing of the probes now contributes to the effectiveness and safety of the procedure. Improved monitoring of the freezing with transrectal ultrasound is also helpful. 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. With modern cryosurgery techniques the risk of fistula is less than 1%, but older studies found fistula in 5-10% of cases.
There is a high incidence of erectile dysfunction with all of the prostate cancer treatments. Almost all patients who undergo cryosurgery to both sides of the prostate will have impotence immediately after the procedure. The impotence can be treated, and many patients will recover erections after one year. We believe that a program to help recovery of erections can significantly improve the chances that a man will recover good sexual function. This program may involve the use of a vaccum erection device or medications to cause erections for the first year after treatment. If nerve-sparing cryosurgery is performed, or if only one side of the prostate is treated (focal cryosurgery) the risk of impotence is less.
Permanent, severe incontinence is rare (approximately 1 percent), but 2-3% of patients will have a small amount of urine leakage that may require them to wear a pad in their underwear.
Other complications, although uncommon given technological advances, include urinary retention requiring transurethral resection of the prostate (TURP), inflammation of the testicle, prostatic abscess and permanent penile numbness. Almost all patients have a temporary need for a catheter to empty the bladder for an average of 15 days.
Focal cryosurgery is a procedure in which only the area of the prostate that contains cancer is frozen. Some doctors are calling this procedure the “Male Lumpectomy” because only the cancer containing area of the prostate is treated, similar to the way that small breast cancers are treated in women. This results in less side effects, and less risk of impotence, than standard cryosurgery. Not all patients are good candidates for focal cryosurgery. The best candidates will have a small amount of Gleason 6 cancer in one or two biopsies from a single side of the prostate. Extensive biopsies of the prostate are performed under anesthesia several weeks prior to the procedure to map out the areas containing cancer and to be sure that more cancer is not present. The main advantage of focal cryosurgery is a low risk of impotence in men with normal sexual function.
Yes. An important use of cryoablation therapy is for patients who fail or develop recurrence after radiation therapy, a treatment called “salvage cryotherapy”. Salvage cryotherapy is the standard treatment for men with a rising PSA after radiation, biopsies that show persistent cancer in the prostate, and no evidence for prostate cancer that has spread outside the prostate.