Radiation is commonly used to treat prostate cancer, killing the cancer cells with high-energy radiation beams. A variety of radiation treatment types may be used. The options are grouped into external and internal radiation treatments. Those delivered from outside the body are external beam radiation therapies. Radiation delivered within the body through radioactive pellets is termed internal radiation therapy or brachytherapy.
External Beam Radiation Therapy
External beam radiation therapy uses a high-dose x-ray machine to deliver radiation aimed at the prostate cancer. The American Cancer Society explains that treatments typically occur five days per week for a total of seven to nine weeks. Prostatic external beam radiation therapy is an option for treating localized cancer. It is also sometimes used to treat prostate cancer that has spread to the bones, causing pain. Radiation treatment for bone metastasis can alleviate symptoms, but it does not cure the disease.
Three-Dimensional Conformal Radiation Therapy
Three-dimensional conformal radiation therapy, also known as 3D-CRT, is an advanced form of external beam radiotherapy. Computer-assisted guidance enables more precise radiation delivery to the tumor, explains the University of California, San Francisco Medical Center. This technique increases the radiation dose delivered to the cancer while decreasing x-ray exposure in the surrounding, healthy tissues.
Proton Beam Radiotherapy
Proton beam radiotherapy is a form of external beam radiation treatment. It involves use of proton beams instead of x-rays to attack the tumor. The advantage of proton beams over x-rays is their capacity to pass through healthy tissues near the tumor with minimal damage, explains the University of Maryland Greenbaum Cancer Center. Proton beam radiotherapy uses computer-assisted delivery guidance, similar to that used with 3D-CRT.
Low Dose Rate Brachytherapy
Low dose rate brachytherapy involves permanent implantation of radioactive pellets into the prostate. The radioactive pellets emit low doses of radiation for weeks to months after placement, explains the American Cancer Society. With low dose rate brachytherapy, also known as permanent brachytherapy, the radiation remains largely confined to the prostate. However, some tissue damage may occur in surrounding structures including the rectum and urinary bladder. Impotence is a well-documented side effect of permanent brachytherapy.
High Dose Rate Brachytherapy
High dose rate brachytherapy employs short-term placement of radioactive pellets into the prostate through temporary tubes. The pellets emit higher doses of radiation than those used with permanent brachytherapy. A series of treatments, up to 15 minutes each, takes place over a period of several days. Bowel, bladder, and rectal irritation are common side effects of high dose rate brachytherapy. Impotence may also occur. The American Cancer Society reports that high dose rate brachytherapy is typically combined with external beam radiation treatment.
References
- UCSF Medical Center: Prostate Cancer, Radiation Therapy
- University of Maryland Greenbaum Cancer Center: Prostate Cancer Treatment Options, Radiation Therapy
- National Cancer Institute: Prostate Cancer Treatment PDQ, Treatment Overview
- American Cancer Society: Prostate Cancer, Radiation Therapy
- RadiologyInfo.org: Prostate Cancer--What are My Treatment Options?
