Prostate Brachytherapy Becoming More Popular
An old technique for treating prostate cancer is enjoying new popularity, thanks to advances in computer technology, says Dr. William J. Ellis of the University of Washington. Brachytherapy, in which radioactive “seeds” are injected into the prostate, is a viable alternative to surgery or traditional radiation therapy for some men with this cancer.
Dr. Ellis and Dr. John C. Blasko of the Seattle Prostate Institute led a course for fellow urologists at the annual meeting of the American Urological Association in Atlanta last week. They described the techniques used in brachytherapy and the criteria for selecting patients.
Usually, a urologist and a radiation oncologist work together to deliver this treatment, the doctors explained. The first step is a volume study in which ultrasound imaging through the rectum is used to measure the size of the prostate so the appropriate dose of radiation can be determined. With the patient carefully positioned, the ultrasound probe sends data to a computer program that digitizes the two-dimensional images and creates a three-dimensional reconstruction of the prostate gland.
After appropriate treatment has been determined, the implant itself takes place. The patient is positioned in exactly the same way as during the volume study, and receives an intravenous antibiotic while under either general or regional anesthetic. Needles containing the radioactive seeds are carefully positioned according to the coordinates determined by the software program. Usually, 25 to 35 needles, each containing two to six seeds, are used. Several imaging systems are used to make sure the seeds are implanted correctly.
Two factors taken into consideration when considering brachytherapy are the extent of the cancer — whether it has spread beyond the prostate — and its rate of growth. If cancer has spread outside the prostate, Dr. Ellis and Dr. Blasko explained, external beam radiation therapy (EBRT) can be used before the brachytherapy. EBRT covers the prostate, the seminal vesicles and the regional lymph nodes.
Another factor to consider before deciding on treatment is the size of the prostate gland. If it is too big, accurate needle insertion is more difficult and the increased number of seeds needed to treat it, may damage the urethra. Dr. Ellis and Dr. Blasko stated that hormone therapy can be used three or four months before brachytherapy to reduce the size of the prostate.
Like any treatment, brachytherapy can present risks and side effects. Complications can include urinary retention, inflammation and/or narrowing of the urethra, incontinence and proctitis (inflammation of the anus and rectum). The most serious of these is urinary retention — medications are often used before and after the brachytherapy to reduce the size of the prostate and improve urination.
Dr. Ellis and Dr. Blasko pointed out that although brachytherapy may cause more urinary irritation than surgery, it’s less likely to cause incontinence and impotence — two reasons it is becoming more popular in treating prostate cancer. Another reason is that the treatment can be done on an outpatient basis.