Radiation therapy is treatment with high-energy rays (such as x-rays) to kill cancer cells or shrink tumors. It may be used:
- As the first treatment for low-grade cancer that is still confined within the prostate gland. Cure rates for men with these types of cancers are about the same as those for men getting radical prostatectomy.
- As part of the first treatment (along with hormone therapy) for cancers that have grown outside of the prostate gland and into nearby tissues.
- If the cancer is not completely removed or comes back (recurs) in the area of the prostate after surgery.
- If the cancer is advanced, to reduce the size of the tumor and to provide relief from present and possible future symptoms.
The radiation 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
Bowel problems: During and after treatment with EBRT, you may have diarrhea, sometimes with blood in the stool, rectal leakage, and an irritated large intestine. Most of these problems go away over time, but in rare cases normal bowel function does not return after treatment ends. Newer radiation techniques may be less likely to cause these problems.
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.
Urinary incontinence: Incontinence means you can't control your urine or you have trouble with leaking. Although this side effect is less common with radiation than surgery, the chance of incontinence goes up each year for several years after radiation treatment. For more information, see the section on urinary incontinence under "Risks and side effects of radical prostatectomy" in the "Surgery" section.
Erection problems, including impotence: Impotence means that a man can't get an erection strong enough to have sex. Some men may still have erections that are not as firm as they once were.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. As with surgery, the older you are, the more likely it is you will have problems with erections. Impotence may be helped by treatments such as those listed in the "Surgery" section, including erectile dysfunction medicines.
Feeling tired: Radiation treatment may cause severe tiredness called fatigue. It may not go away until a few months after treatment stops.
Lymphedema: Fluid build-up in the legs or genitals (described in the "Surgery" section of this document) 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)
Permanent or low dose brachytherapy uses small radioactive pellets (each about the size of a grain of rice) that are put into the prostate. Sometimes these pellets are referred to as "seeds." The doctor puts the seeds in place by inserting hollow needles through the skin between the anus and the scrotum during a minor operation. Radiation from the seeds travels a very short distance, so the seeds can put out a very large amount of radiation to a very small area. Because they are so small, they cause little discomfort and are often left in place after their radioactive material is used up. As a rule, this treatment is used only in men with early stage prostate cancer that is slow growing. It may not be a good option for men with large prostate glands.
Another form of brachytherapy is called temporary or high dose brachytherapy. In this type, needles are used to place soft tubes (called catheters) in the prostate. A strong radioactive substance is placed in these catheters for 5 to 15 minutes. The needles are then taken out, but the catheters are left in place. You will stay in the hospital for this treatment. Usually 3 treatments are given over a couple of days. After the last treatment the catheters are removed. Often this treatment is combined with external radiation, given at a lower dose than it would be if used alone.
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.
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