Radiation therapy uses high-energy x-rays to kill cancer cells. There are 2 types of radiation therapy used for prostate cancer:

• External beam: radiation beamed from a machine outside the body
• Internal: radiation emitted by tiny radioactive seeds implanted in the prostate gland

During external radiation, the primary target is the prostate gland itself. Areas around the prostate and the pelvis can also be exposed to varying doses of radiation. Side effects may include diarrhea, frequent and painful urination, rectal irritation or bleeding, and impotence.

With internal radiation, tiny radioactive seeds or implants are placed directly into the prostate gland to kill cancerous cells. This is also known as interstitial implantation or brachytherapy.

Comparing Internal and External Radiation

Compared with external beam radiation, brachytherapy may offer certain benefits:

• The seeds can be implanted precisely in the tumor.
• Brachytherapy potentially can result in less damage to surrounding tissue because a high dose of radiation can be given to tissues in the immediate area of the tumor, while minimizing the damage to healthy tissues such as the rectum and bladder.
• Side effects may include urinary incontinence, impotence, and bowel problems such as burning, pain, and diarrhea.

Other Treatment Options

Learn about other treatment options including hormonal therapy, surgery, chemotherapy, or watchful waiting (observation).