Seed Implantation and Cryosurgery:
In the 1990s, with the advent of new technologies and procedures, doctors began to return to the two treatments that had not been successful in the past: seed implantation and cryosurgery. Although many physicians advised patients that these treatments were experimental and should be avoided, many patients chose to ignore them. Today, as a result of the ease of the operation, the minimal side effects, and lowered cost, these two approaches are getting a great deal of attention. In many cases, urologists are being trained to perform either cryosurgery or seed implantation. These physicians are at the forefront of what are potentially more acceptable and, hopefully, more effective therapies for prostate cancer.
It is possible that radical prostatectomy and external beam radiation will become obsolete in the future because of the success of investigational treatments such as cryosurgery. Why? Because these treatments are getting results similar to or better than those for radical prostatectomy and external beam radiation. They have less morbidity, they can be used as salvage treatments, and they can be repeated. Patients can receive these treatments in less time, and they are less costly.
Cryosurgery, also called cryoablation surgery, is a technique in which six to eight cryoprobes, small tubes utilizing argon gas, are inserted between the scrotum and anus. They enter the prostate gland to freeze and thus kill prostate cancer cells. Freezing of the prostate was first done about 30 years ago; however, it was abandoned because of severe side effects. With the advent of transrectal ultrasound, it reemerged as a viable technique and an alternative to radical prostatectomy and radiation. During cryosurgery, a 2- hour procedure performed under anesthesia, the prostate is frozen with argon gas circulated in cryoprobes.
The physician monitors the procedure using transrectal ultrasound and thermosensors to assure a killing temperature (-20 °C to -40 °C) at the site of the cancer.
Seed implantation is a medical procedure in which a team of physicians (a urologist, radiation oncologist, and radiation physicist) uses a radioactive source to irradiate prostate cancer cells, while minimizing radiation to the surrounding tissues. Patients with low to intermediate Gleason scores usually receive 1-125 seeds, which have a half-life of 60.2 days; patients with higher Gleason scores usually receive palladium-103 seeds, which have a half-life of 17.0 days. In addition, these higher-risk patients often receive hormonal therapy, external beam radiation, or both. The number of seeds delivered can vary from 50 to 120, depending on the anatomy of the patient and the size of his prostate.
Is seed implantation as effective as radical prostatectomy? Will it become the gold standard for treating prostate cancer patients? It is difficult to say. However, we do know this: many, many radiation oncologists who specialize in external beam radiation have become more proficient in seed implantation, as have many urologists. Although no one has taken a survey of the number of doctors “switching over” to seed implantation, we believe that it is gaining momentum.
A 12-year study done by Dr. Haakon Ragde indicates that seed implantation is ”as good or better” than radical prostatectomy. The Northwest Prostate Institute in Seattle has reported on 215 patients treated with brachytherapy and followed for
12 years. The overall control rate was 79 percent, which is equal to or better than the gold standard of 70 percent for radical prostatectomy. Radiation oncologists in Washington, D.C. (Cancer, July 1, 2000) found that 82 of these patients were considered at high-risk for cancer outside the capsule based on the size of the prostate nodule, Gleason grade, and PSA level; thus, they were treated with both seeds and external beam radiation. Obviously, not all patients should undergo seed implantation only. It appears that only low-risk patients are eligible for this form of treatment. Intermediate- and high-risk patients should get seeds and external beam radiation.
Seed implantation generally has fewer side effects than does radical prostatectomy or cryosurgery. In addition, the recuperation time for most patients treated with brachytherapy is much shorter than with radical prostatectomy, and the procedure is less costly as well.