Radiation therapy uses high-energy X-rays, either beamed from a machine (external beam irradiation) or released by radioactive seeds implanted in the prostate (brachytherapy), to kill cancer cells.
Radiation can be used:
External Beam Irradiation The location of the prostate is determined prior to treatment, and the skin is marked with ink to guide the radiation to the right area. Electromagnetic radiation is given to the prostate in the same way an X-Ray is done. Treatment is given five times each week (Monday through Friday) for seven to eight weeks. Each session lasts about 15 minutes and the treatment itself is painless.
Side Effects Most side effects involve the rectum and bladder. They may include diarrhea, rectal bleeding, urinary frequency, incontinence and bleeding from the bladder. Side effects are usually mild and disappear after treatment has stopped. External beam irradiation can also cause tiredness, that may not improve until one or two months after treatment is completed.
Twenty five to 50 per cent of men lose their ability to obtain an erection within one to two years following treatment. (Impotence does not usually begin right after treatment). It is believed that over time the radiation takes a gradual toll on the nerves and blood vessels that control erection.
Cure and Recurrence Rates Long-term results are dependent on the stage and grade of the tumour at the time of diagnosis. In general, the odds of being alive 10 years after radiation treatment are around 70 per cent and there is a 40 per cent chance the cancer will return. In favourable cases, however, the odds are significantly better.
Radiation therapy success rates seem comparable to those for surgery in men whose life expectancy is seven to 10 years. There is considerable debate, however, about its effectiveness (compared with surgery) in men with longer life expectancies.
Brachytherapy Brachytherapy is a form of internal radiation. Radioactive material in the form of small “seeds” are placed directly in the cancerous tissue during a procedure that takes one to two hours, under local anesthesia. Patients usually go home the same day. The seeds, each about the size of a grain of rice, release radiation for up to six months, and then remain permanently and harmlessly in place.
The advantage of brachytherapy is that it targets the cancerous areas of the prostate and it has less of an impact on healthy cells in areas like the rectum and bladder.
Brachytherapy is a relatively new treatment and long-term effects are not yet known. However, at five years more than 90 per cent of men who undergo this procedure remain disease-free.
Brachytherapy is not suitable for all patients. It is a good treatment for men in the early stages of prostate cancer (generally, Gleason grade of 6 or less and PSA less than 10) and small prostates (volume less than 50 cubic centimeters). Men with larger prostates (50 to 70 cc's) can take hormone therapy to reduce the size of their prostates and then try brachytherapy.
Gleason Scoring
Side Effects Side effects usually disappear in four to six weeks. Common problems include incontinence, burning with urination, blockage of urinary flow and soreness in the area of the implant. Sexual impotence occurs in about 15 per cent of men under the age of 70 and 30 to 35 per cent of men over 70.