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Q. How does targeted cryosurgery treat prostate cancer?
Targeted cryosurgery, a procedure developed by Endocare (Nasdaq: ENDO), is the use of cryosurgery (application of extreme cold to destroy tissue) in combination with ultrasound and temperature monitoring to precisely destroy cancer cells in and around the prostate gland. When extreme cold is introduced into the prostate gland, the prostate tissue is destroyed, including cancerous cells. Physicians have found that targeted cryosurgery is most effective for patients with Stage T1 through T3 prostate cancer. Unlike other surgical procedures, targeted cryosurgery can be repeated if prostate cancer recurs.
During targeted cryosurgery, a patient is first treated with epidural anesthesia. A thin catheter that circulates warm fluid is placed in the urethra to protect it from cold temperatures. Next, six to eight slender cryoprobes are inserted through a small incision into the prostate gland. Liquid argon is circulated at the tips of the cryoprobes, freezing the entire prostate gland. This begins the cooling process, during which the cryoprobes freeze tissue symmetrically around the probe tip. Tissue that reaches -40° C is destroyed. After approximately 10 minutes, the physician completes the first freeze cycle and then administers another treatment to help ensure that all cancer cells are killed. The entire procedure lasts about one to two hours.
Q. What happens following the targeted cryosurgery procedure?
Following the targeted cryosurgery procedure, the patient waits in the recovery room until the anesthesia wears off and then, depending on how he feels, can return home immediately or spend the night at the hospital. The patient goes home with a catheter in place to help with urination the week following treatment. In general, patients can resume a normal lifestyle immediately after the procedure, but strenuous activity should be avoided for a few weeks.
Some patients may experience mild soreness for two to three days following targeted cryosurgery; however, this side effect is common among all surgical prostate cancer treatments. To relieve any soreness or swelling, patients can place an ice pack on the abdomen. Long-term side effects of targeted cryosurgery are similar to other therapies and may include impotence, bladder outlet obstruction, pelvic pain, chronic urgency, rectal injury, and incontinence. The rate of incontinence after targeted cryosurgery is lower than with other therapies. Patients should be aware that impotence occurs in 80% to 90% of patients who undergo targeted cryosurgery. This is due to the intentional freezing of tissue outside the prostate gland to kill cancer cells that may have already spread beyond the prostate capsule.
Freezing tissue beyond the prostate capsule is an important decision that helps in curing the cancer and not leaving behind viable prostate tissue that could become malignant. Although this process may damage the nerves that allow a man to get an erection, most urologists advise treating such tissue because if not, cancer cells may still remain.
Q. How effective is targeted cryosurgery in the treatment of prostate cancer?
In the July 2000 issue of the peer-reviewed journal Urology, a comparative study of 163 prostate patients treated with two methods of cryosurgery reports that 97% of patients treated with targeted cryosurgery were cancer-free after six months. In another study presented at the 1998 World Endo-Urology Conference, 97% of patients treated with targeted cryosurgery showed no signs of cancer at one year. Five-year combined data for both traditional cryosurgery and targeted cryosurgery show that of 988 patients treated, 82% had negative biopsies.
Q. Who is a candidate for targeted cryosurgery?
The best candidates for cryosurgery are men with Stage T1-T3 disease and high Gleason scores and prostate-specific antigen levels. In these patient populations, cryosurgery has been found to be safe, effective, and medically necessary. Because targeted cryosurgery can be repeated if all the cancer cells aren’t destroyed, some patients choose the treatment for this reason. Others turn to targeted cryosurgery for treatment if radiation therapy or brachytherapy has failed.
Q. How many prostate cancer patients have been treated with cryosurgery?
Several thousand men have received cryosurgery to treat prostate cancer. This therapy, first introduced in the 1960s, has seen dramatic improvements during the past five years with the use of temperature monitoring, argon-based cryogen, and ultrasound guidance techniques. The temperature monitoring and ultrasound visualization used in targeted cryosurgery allow the physician to precisely freeze the prostate gland while sparing other critical areas of surrounding tissue. The use of argon-based cryogen provides physicians with better control and accuracy, ensuring that a freezing level of -40° C is achieved and confined to a specific area.
Source: Endocare, Irvine, CA. Web: www.endocare.com. (For more information, see "HCFA sets April 1 to cover cryoablation," in this issue.)