Stephan L. Werner, M.D., F.A.C.S.
Radiation therapy is frequently used to treat prostate cancer for cure. It is more often given to the older, or sicker patient, as it is less invasive than surgery, but may be used effectively in younger patients as well. In high Gleason grade, (8, 9 and 10), cancers, radiation therapy has poorer long term results than surgical therapy, although some newer protocols combining external beam and seed irradiation with hormone therapy, (neo-adjuvant and adjuvant), may be promising. There are several different forms of radiation therapy: external beam, brachytherapy or seed implantation, high dose interstitial radiation, and several forms of combined therapy. During and for about 6 months after any form of radiation you should avoid taking antioxidants such as Vitamin E, Vitamin D, Selenium etc... as they may counteract some of the beneficial effects of radiation.
External beam therapy is administered as an outpatient over a 5 to 8 week period. Usually 5 treatments, lasting several minutes are given weekly. Several different "ports" are used so that the tissues surrounding the prostate get less radiation than the cancer. Most external beam radiation is given by the 3-D conformal radiation technique, using a computer to control the radiation closely to the prostate. An even newer modification is IMRT, intensity modulated radiation therapy, a more intensive 3-D mode, that confines the radiation more tightly to the prostate, decreasing side effects. Frequently the patient will feel very tired during the later stages of radiation, and temporary or long term bladder or bowel irritability or bleeding may occur. Impotence eventually occurs in about 50% of those receiving radiation treatment, but incontinence is rare unless there has been prior prostate surgery. The results, in terms of cure, are similar to surgery for about 12 years. There are several varieties of external beam radiation such as conformal, rotational or wide field, IMRT and proton beam irradiation, the discussion of which is better left to the radiation oncologist. We use several radiation centers in the area for these types of therapy.
Interstitial radiotherapy refers to the placement of radioactive sources into the prostate itself. It is done in order to give very high doses of radiation to the cancer, while giving only lower doses to the surrounding tissues. There are two types of interstitial irradiation, the more common is brachytherapy or seed implantation, and the newer, rapid interstitial therapy.
Seed implantation or Brachytherapy involves tiny, (much smaller than grains of rice), radioactive metal seeds, (Iodine129 or Palladium103), implanted permanently into the prostate. The radioactivity decreases rapidly over several days or weeks, but very high doses of radiation are given to the cancer cells. Two to three times as much radiation can be delivered compared to external beam therapy, with much less radiation of the surrounding tissues. Brachytherapy requires in and out surgery under anesthesia, to implant the seeds. The seeds are implanted through needles under some form of imaging, (sonography, x-ray or CT scan). Seed implantation has only been available since the late 1980's. To date the results have been as good as other forms of radiation or surgery. Dr. Werner does all the seed implants for the group and works at Doctors Community Hospital in Lanham or Prince Georges Hospital Center in Cheverly. Post seed implant instructions
Rapid interstitial therapy is a newer form of therapy that is being offered in a few centers. Similar to seed implantation, plastic tubes are inserted into the prostate, and rapid dose radioactive sources are placed in the tubes for several days. The sources and the tubes are then removed. The procedure requires a several day hospital stay, but has the advantage that the seeds are removed after treatment. There is no long or significant short term data as to the efficacy of this treatment which may be offered in the near future.
Combined therapy has many different meanings to different people. It may refer to combined external beam and brachytherapy, or combined hormonal and radiation therapy. The various therapies are an attempt to improve the long term results of therapy. We use various forms of these therapies in selected patients, such as those with extensive cancer in the prostate or a high likelihood of local extension, i.e. stage C disease.
Neoadjuvant combined therapy, combines a form of radiation with short term hormonal therapy. In many centers, hormone therapy with LHRH is started at least two months before radiation is started and continued for two months to three years after radiation therapy is completed. Hormonal therapy kills many cancer cells and weakens many others, perhaps increasing the efficacy of the radiation therapy. Long term data is not available at the present but we do suggest neoadjuvant therapy to our intermediate and high risk patients undergoing all forms of radiation.
Stephan Werner, M.D., F.A.C.S.
Werner - Francis Urology Associates llc - Mid Atlantic Urology Associates llc
Greenbelt - Bowie - Laurel Maryland
(301) 441-8900 Fax (301) 982 0453
7500 Hanover Parkway Suite 206 Greenbelt, MD 20770