Radioactive Seed Implantation
Q. What is seed implantation?
A. Seed implantation - otherwise known as "brachytherapy" - refers to the placement of radioactive material into tissues. Prostate brachytherapy refers to utilizing a minimally invasive technique to place radioactive sources (contained within a metallic casing) directly into the prostate. Hollow needles are placed into the prostate in the operating room, and the radioactive seeds are inserted into the prostate through the hollow needles. Ultrasound and computerized treatment planning in the operating room achieve accurate placement of seeds.
The advantage to this approach of delivering radiation is the ability to accurately deliver a high dose of radiation directly into the prostate while minimizing the radiation dose to the nearby tissues and organs. Patients are usually discharged from the hospital within hours of the procedure, and patients return to normal function within several days.
Q. Is seed implantation a new procedure?
A. The concept of seed implantation into tumors was first utilized 100 years ago. The treatment of prostate cancer with brachytherapy dates back to the 1970s, using relatively primitive techniques. Modern prostate brachytherapy techniques were developed in the late 1980s and were further perfected in the 1990s with the advent of improved ultrasound technology. In 2000, we implemented real-time 3-D intraoperative computerized treatment planning to assure optimal placement of radioactive sources and minimize the dose to the bladder and rectum. These tools have enabled us to minimize side effects and maximize cure rates. Follow-up data have recently been published with excellent 15 -year results, making prostate brachytherapy a viable treatment option for select patients.
Q. Who is a candidate for seed implantation?
A. Men with prostate cancer that is localized to the prostate (i.e., PSA<10, Gleason Score six or under, or clinical T1 C or T2A) are candidates for prostate brachytherapy. Men with more advanced disease - disease just beyond the capsule of the prostate - may be candidates for seed implantation after five weeks of external beam radiation. Patients might not be candidates if the prostate is bigger than 50 gm or if the patient has had Transurethral Resection of the Prostate (TURP) procedure.
Q. How is seed implantation performed?
A. The urologist and radiation oncologist perform seed implantation. A volume measurement of the prostate is performed, using transrectal ultrasound by the urologist. Appropriate seeds are ordered, and the date of the procedure is determined. On the day of the procedure, you will meet the anesthesiologist and can have either a spinal or general anesthetic. Once you are asleep in the operating room, the urologist remeasures the prostate. Hollow steel needles are placed into the prostate through the perineum (the skin in front of the rectum and behind the scrotum). The radiatiori oncologist then uses a specialized gun to place rows of seeds into the prostate through the needles. The intraoperative computer is then used to model the prostate and determine where additional needles and seeds should be I placed. Once this is accomplished, the urologist looks into the bladder and inserts a Foley catheter. The entire procedure takes less than one hour. Once you wake up from the anesthetic, the Foley catheter is removed, and you are discharged from the hospital.
Q. What happens to the seeds?
A. The radioactive seeds stay inside of you forever. The radiation produced by the seeds goes away (decays) over time. If Palladium Pd 103 seeds are used, the radiation decays to nearly undetectable traces in three months; if Iodine I125 seeds are used, the radiation decays to nearly undetectable amounts in six months.
Q. Do radiation precautions need to be followed?
A. The body blocks most of the radioactivity that is produced by the implant. However some radioactivity may be given off during the time periods listed above. Bodily fluids are never radioactive. The Nuclear Regulatory Commission (NRC) has not recommended radiation precautions for implant patients. Nevertheless we recommend the following:
- Children should not sit on your lap for more than five minutes a day for two months after an implant
- Pregnant women should avoid more than a few minutes of close contact with you for two months after an implant.
Q. What are the side effects?
A. Ten percent of patients will require a catheter for several days after the implant. Very few patients will need a catheter for an extended period. You may experience blood in your urine, which will resolve on its own. Few, if any patients, develop an infection, as all patients receive antibiotics before the procedure.
The most common side effects are related to urinary symptoms. You will experience some degree of urinary frequency or urgency and possibly burning with urination and the need to get up at night to urinate more frequently. After a palladium implant, urinary symptoms usually last from two weeks to six months, and after an iodine implant, these symptoms can last from two weeks to nine months. There are medications that can help alleviate these symptoms in most cases. Patients rarely experience rectal irritation or bleeding, and it is rare for an implant to result in damage to the bladder or rectum. Impotence has been reported in 15 percent of patients, two years after the implant and 40 percent of patients, four years after the implant. Patients often experience a "dry ejaculate," whereby they are able to have a normal-feeling erection and intercourse, but their ejaculation is dry.
Q. What type of follow-up care is necessary?
A. You will be seen after the implant by your urologist and radiation oncologist. You will undergo a CT scan of the pelvis one month after the implant to evaluate the implant dosimetry, and a PSA test and physical exam at least every six months. We expect the PSA to decline to its maximum extent by two years after implant.
Q. What about diet and activity after the procedure?
A. Your usual diet can be resumed the day after the procedure. We ask that you avoid heavy lifting or strenuous physical activity for the first two days after the procedure. After that, normal activity (including driving) can be resumed.
Q. Does private insurance or Medicare cover seed implantation?
A. Both private insurance and Medicare will pay for this procedure.
Q. Who do I contact for more information?
A. Patients who would like additional information regarding seed implantation should call (412)-281-1757 and ask to be seen at the Allegheny Prostate Center. Let the receptionist know that you are interested in seed implantation, and she will schedule you accordingly.