Radiation therapy uses high doses of radiation, such as X-rays, to destroy cancer cells. The radiation damages the genetic material of the cells so that they can't grow. Although radiation damages normal cells as well as cancer cells, the normal cells can repair themselves and function, while the cancer cells cannot.
Radiation therapy may be used alone or combined with hormonal treatment to treat prostate cancer. It is most effective in treating cancers that have not spread outside the prostate. But it also may be used if the cancer has spread to nearby tissue. Radiation is sometimes used after surgery to destroy any remaining cancer cells and to relieve pain from metastatic cancer.
Radiation is delivered in one of two ways.
Sometimes treatment combines brachytherapy with low-dose external radiation. In other cases, treatment combines surgery with external radiation or hormone therapy may be used along with brachytherapy.
Before radiation therapy is scheduled, your doctor probably will order a bone scan and CT scan to find out whether the cancer has spread to other parts of your body. If it has, your doctor may offer you the option of a clinical trial for treatment.
Side effects may last only as long as the treatment, or they may continue and become chronic. Some side effects occur after treatment, such as erection problems. For some men, this problem gets gradually worse over the course of several years after treatment. The long-term effects of radiation therapy on the main body systems are not yet known. Side effects include:1
Radiation therapy is used for:
For early-stage prostate cancer, prostatectomy and radiation appear to work equally well. Radiation appears to work as well as prostatectomy and active surveillance for most men over 65 who have early stage prostate cancer (stages I and II, also called localized prostate cancer). For men younger than 65, treatment with surgery may help them live longer.2
For treating low-risk prostate cancer, brachytherapy alone works well.3
For treating advanced prostate cancer that has grown beyond the prostate but not into lymph nodes or bones, external-beam radiation combined with hormone drugs can work better than surgery. This treatment often results in controlling cancer growth and in many years of disease-free survival.1
Radiation therapy also works well to treat pain when prostate cancer has spread to the bone.4
Side effects are common. Some men develop long-term problems that may have a significant impact on their quality of life. Long-term problems that can be caused by radiation treatment include:
The goal of radiation therapy is to deliver the highest dose possible to the prostate while protecting the rest of the nearby organs (such as the bladder and rectum) from unnecessary radiation. Newer ways of giving radiation, such as 3D-CRT, IMRT, and proton beam therapy, are more accurate. This has helped to reduce problems caused by radiation.
- National Cancer Institute (2012). Prostate Cancer Treatment (PDQ)—Health Professional Version. Available online: http://www.cancer.gov/cancertopics/pdq/treatment/prostate/HealthProfessional.
- Lu-Yao GL, et al. (2010). Outcomes of localized prostate cancer following conservative management. JAMA, 302(11): 1202–1209.
- Zelefsky MJ, et al. (2011). Cancer of the prostate. In VT DeVita Jr et al., eds., DeVita, Hellman and Rosenberg's Cancer: Principles and Practice of Oncology, 9th ed., pp. 1220–1271. Philadelphia: Lippincott Williams and Wilkins.
- D'Amico AV, et al. (2012). Radiation therapy for prostate cancer. In AJ Wein et al., eds., Campbell-Walsh Urology, 10th ed., vol. 3, pp. 2850–2872. Philadelphia: Saunders.
Last Revised: September 12, 2012
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