Radiation therapy for prostate cancer: external beam radiation therapy

During external beam radiation therapy (EBRT) for prostate cancer, radiation is delivered from an outside source that targets the prostate gland. It is a painless procedure that is like getting an x-ray.

Generally, your loved one will receive radiation treatment 5 days a week for 7 to 9 weeks. The set-up time each day usually takes longer than the actual treatment, which should only take a few minutes.

The first step is a series of tests that are used to help pinpoint the areas that need to be treated. This helps to minimize damage to healthy tissues. These tests may include MRIs, CT scans, and x-rays.

Once these areas are located, your loved one may receive small ink spots on his skin so the technicians will know where to aim the treatment.

Some medical centers now do a CT scan every day for the first week or two to get a “baseline” of how much a man’s prostate gland moves in position from day to day. Then the CT scan is used at set intervals to help ensure accuracy. This is a good question to ask about prior to radiation therapy for prostate cancer.

Here are the 3 techniques that are commonly used:

Three-dimensional conformal radiation therapy: computers determine the exact location of the prostate and where high energy x-rays will be delivered. It may involve the use of a plastic body mold (like a body cast), which helps a man stay in one position. According to the American Cancer Society, this method appears to be as effective as standard EBRT, but offers lower side effects.

Intensity modulated radiation therapy: a computer-guided machine moves a man around as radiation is delivered from different angles. The amount delivered can be increased or decreased, depending upon the area of delivery.

Another newer type of intensity modulated radiation therapy for localized prostate cancer is called stereotactic radiotherapy (or radiosurgery). You may have heard it advertised as CyberKnife or GammaKnife. This radiation treatment for prostate cancer is usually given over a period of 1 to 5 days.

Conformal proton beam radiation therapy: This approach uses proton beams that, unlike x-rays, do not release energy before and after they reach the desired area of the prostate. It is believed that this may cause less damage to healthy tissues, but more long-term studies are needed to confirm this. It is also not as widely available as other forms of radiation therapy for prostate cancer.

Potential side effects

After radiation therapy for prostate cancer, some men may experience bowel problems, such as diarrhea, blood in the stool, loose stools, and rectal pain. These problems are usually temporary, but can sometimes be permanent. Your loved one may need to urinate more frequently (a problem which may continue), or experience burning while urinating. He may also see blood in his urine.

There is also a chance of urinary incontinence and impotence. These problems may develop over time. Other factors, such as the age of the man, and whether he previously had any urinary or erectile problems, may also influence the development of these side effects.

According to the American Cancer Society, after several years, the impotence rate for radiation for prostate cancer is pretty similar to that of surgery. Incontinence may be less common, but the risk increases each year for a few years after radiation treatment.

Your loved one may feel tired, especially toward the end of his radiation therapy for prostate cancer. This tiredness may last for several months after treatment has ended.

Always discuss everything you read on this web site with a qualified medical professional.

Updated 10/09



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