Radiation therapy uses high energy x-rays to destroy cancer cells. Special tools and dosing will help to kill as much of the cancer as possible while minimizing the effect on nearby healthy tissue. A radiation oncologist will customize the treatment dose for individual needs.
Radiation therapy may be given:
- As a primary treatment instead of surgery
- After surgery to kill any remaining cancerous tissue
- For metastatic cancer to relieve symptoms and extend survival time
Types of radiation therapy used for prostate cancer:
External Beam Radiation Therapy
External radiation passes radiation from a machine outside the body, through the skin to cancer area. Delivery methods help to deliver the maximum amount of radiation possible to the tumor while minimizing exposure to healthy surrounding tissue. Methods to improve delivery include:
- 3D conformal radiation therapy (3D-CRT)—Imaging tests are used to map the prostate. Once the tumor is located, radiation beams are directed at it from different angles.
- Intensity modulated radiation therapy (IMRT)—A computerized machine rotates around the patient to deliver radiation to the tumor site. Dosage can be weakened or strengthened depending on the target tissue. Another type of IMRT that can be used is called volumetric modulated arc therapy (VMAT).
- Stereotactic body radiation therapy (SBRT)—Uses imaging to deliver larger doses of radiation to the tumor site. The larger doses may allow the treatment period to be shorter.
- Proton beam radiation therapy—An alternative to using x-rays, proton beams may allow for larger doses to be delivered because they are more precise and less harmful to surrounding tissue.
This is also called internal radiation therapy. Radioactive material in a specialized container is placed near the tumor. This allows a higher dose of radiation to be delivered directly to the tumor. To treat prostate cancer, a brachytherapy is done with a process called seed implantation. Small pellets are placed in the prostate gland. The seeds can be:
- Permanent—Low-dose radiation seeds are placed through the perineum, the area between the scrotum and anus. Radiation is emitted over for a long period of time, sometimes months.
- Temporary—High-dose radiation is delivered via catheters inserted through the perineum. Radiation is given for up to 15 minutes before being removed. The procedure may be given up to 3 times over the course of 2 days. The catheters stay in place until the treatments are done.
In some cases, brachytherapy may be combined with external beam radiation therapy.
Alpha emitter radiation therapy delivers radioactive substances to cancer cells through an IV. The radiation kills cancer cells that have spread to the bones.
Side Effects and Management
Complications of radiation therapy to the pelvic area may include:
- Anal and/or rectal irritation causing:
- Blood in the stool
- Pain during bowel movements
- Bladder irritation causing:
- Increased frequency of urination
- Narrowing of the urethra, the tube that carries urine out of the body from the bladder—rare
- Erectile dysfunction
A variety of treatments are available to help manage side effects of radiation therapy, such as dry, irritated skin, nausea, vomiting, and fatigue due to anemia. Sometimes adjustments to treatment doses may also be possible. The earlier side effects are addressed, the more likely they will be controlled with a minimum of discomfort.
- Reviewer: EBSCO Medical Review Board Mohei Abouzied, MD, FACP
- Review Date: 09/2016 -
- Update Date: 04/19/2017 -