Radiation Therapy

What is radiation therapy?

Radiation therapy uses high-energy rays to kill or shrink cancer cells, and to decrease their ability to divide. Radiation is often used to treat prostate cancer that is still confined to the prostate gland, or has spread only to nearby tissue. If the disease is advanced, radiation may be used to reduce the size of the tumor and to provide relief from symptoms.

What are the types of radiation therapy?

There are generally two types of radiation therapy:

  • External radiation (external beam therapy). A treatment that precisely sends high levels of radiation directly to the cancer cells. The machine is controlled by the radiation therapist. Since radiation is used to kill cancer cells, special shields may be used to protect the tissue surrounding the treatment area. Radiation treatments are similar to getting X-rays; they are painless and usually last a few minutes. This type of radiation therapy may be given daily for several weeks.

  • Internal radiation (implant therapy). A procedure that uses small, radioactive seeds (each about the size of a grain of rice) that are implanted directly into the cancerous prostate tumor. The implanted seeds may be left in permanently or may be only temporary. The permanent seeds emit small amounts of radiation for a period of weeks or months. Temporary brachytherapy uses a stronger radioactive source that is put into the prostate for about 10 minutes at a time and then removed. It is usually given a few times over a couple of days. 

What are side effects of radiation therapy?

As each man's individual medical profile and diagnosis is different, so is his reaction to treatment. Side effects may be severe, mild, or absent. Be sure to discuss with your cancer care team any or all possible side effects of treatment before the treatment begins.

Possible side effects of external beam radiation therapy for prostate cancer may include:

  • Diarrhea (with or without blood in the stool) and colitis (irritation of the large intestine)

  • Problems associated with urination (more frequent urination, burning sensations, blood in urine, incontinence)

  • A degree of impotence (inability to achieve or maintain an erection), which may occur within two years of radiation therapy

  • Fatigue, especially during the later weeks of treatment

Along with the above effects, additional possible side effects of internal radiation therapy for prostate cancer may include:

  • Slight bleeding soon after the seeds are placed

  • Occasional loss of the seeds when urinating

  • Irritation of the rectum in a small percentage of men