Prostate Cancer Overview

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Treating Prostate Cancer TOPICS

Radiation therapy for prostate cancer

Radiation therapy is treatment with high-energy rays (such as x-rays) to kill cancer cells or shrink tumors. It may be used to treat cancer in (and near) the prostate. It is also used to treat areas of cancer spread.

Radiation to treat prostate cancer may come from outside the body (external beam radiation) or from radioactive materials placed directly in the tumor (brachytherapy or internal radiation).

External beam radiation therapy (EBRT)

For this treatment, beams of radiation are focused on the prostate gland from a machine outside the body. This type of radiation can be used to try to cure earlier stage cancers, or to help relieve symptoms such as bone pain if the cancer has spread to a specific area of bone.

Each treatment lasts only a few minutes. Men usually have 5 treatments per week in an outpatient center over a period of 7 to 9 weeks. Each treatment is painless and lasts only a few minutes, although the setup time — getting you into place for treatment — takes longer.

Today, standard EBRT is used much less often than in the past. Newer methods allow doctors to be more accurate in treating the prostate gland while reducing the radiation exposure to nearby healthy tissues. Some of these methods you may hear about are 3-dimensional conformal radiation therapy (3D-CRT), intensity modulated radiation therapy (IMRT), and conformal proton beam radiation therapy. These methods seem to offer better chances of increasing the success rate and reducing side effects. If you are having one of the newer methods, your doctor can tell you more about it.

Possible side effects of external beam radiation therapy

Some common short-term side effects include:

  • Bowel problems: Diarrhea, sometimes with blood in the stool, rectal leakage, and an irritated large intestine are problems that usually go away over time, but in rare cases they don’t
  • Bladder problems: You might need to urinate more often, have burning while passing urine, and maybe see blood in your urine. Bladder problems usually get better over time, but they last in about 1 out of 3 men, with the most common problem being the need to urinate often.
  • Feeling tired: Radiation treatment may cause severe tiredness. It may not go away until a few months after treatment stops.

Some side effects may not be seen right away, but are more likely to last a long time, such as:

  • Trouble controlling urine (urinary incontinence): This is less common with radiation than surgery, but the chance of incontinence goes up each year for several years after radiation treatment.
  • Erection problems, including impotence (or erectile dysfunction): Some men may have erections that are not as firm as they once were, while others might not be able to get an erection strong enough to have sex. Erection problems usually do not happen right after radiation therapy but slowly develop over a year or more. After a few years, the impotence rate after radiation is about the same as that after surgery.
  • Lymphedema: Fluid build-up in the legs or genitals is possible if the lymph nodes receive radiation.
  • Urethral stricture: The tube that carries urine from the bladder out of the body may, rarely, be scarred and narrowed by radiation. This can cause problems with urination, and may need further treatments to open it up again.

Brachytherapy (internal radiation)

For brachytherapy, radioactive materials are put in or near the place to be treated. For prostate cancer, the materials are placed in the prostate. The risk of side effects to other areas is lower, because the radiation travels only a short distance. There are 2 main types of brachytherapy:

  • Permanent or low dose brachytherapy uses small radioactive pellets or “seeds” that are put into the prostate and not removed. Each seed is about the size of a grain of rice. .
  • Temporary or high dose brachytherapy uses stronger radiation sources that are only left in place for a short amount of time (less than 15 minutes). These radiation sources are put into soft tubes (called catheters) that have been placed in the prostate. Usually 3 treatments are given over a couple of days and you stay in the hospital during that time. After the last treatment the catheters are removed.

Possible risks and side effects of brachytherapy

If you have pellets that are left in place, they will give off small amounts of radiation for several weeks. Even though the radiation doesn't travel far, you may be told to stay away from pregnant women and small children during this time. You may be asked to be careful in other ways, too, such as wearing a condom during sex.

For about a week after the pellets are put in place, there may be some pain in the area and a red-brown color to the urine. There is also a small risk that some of the seeds might move to other parts of the body, but this is rare.

Like external radiation treatment, this approach can have side effects such as problems with the bladder and bowel, as well as erection problems. Talk to your doctor if you have any problems. Often there are medicines or other methods to help.

More details about radiation therapy for prostate cancer can be found in our document Prostate Cancer.


Last Medical Review: 08/27/2013
Last Revised: 02/25/2014