Radiation Therapy for Colorectal Cancer
External Beam Radiation Therapy
In external beam radiation therapy, radiation is produced by a machine called a linear accelerator. Short bursts of x-rays are fired from the machine at your cancer. The x-rays come out in a square-shaped manner, and the radiation oncologist designs special blocks to shape the radiation beam so that it treats the cancer and as little normal tissue as possible.
You may be treated with conventional external beam treatment, or your doctor may recommend one of several alternatives. These other methods are often designed to deliver high doses of radiation to the tumor site while still limiting the exposure of surrounding normal tissues.
- IMRT (Intensity modulated radiotherapy) uses multiple thin beams to focus the highest does of radiation in the area of the tumor.
- High dose brachytherapy uses catheters and tubes to deliver an extra dose of radiation to the tumor site and may occasionally be used to boost the radiation delivered to the site of a rectal tumor.
Radiation of a Tumor
Radiation therapy can be given to treat cancer at its initial site or once it has spread. In some cases, once cancer has spread, radiation is no longer curative. However, the treatments can help resolve problems that the cancer may be causing, including pain and weakness.
Many people believe that once you have received a certain dose of radiation you can no longer get any more treatment. It is true that each tissue in the body can only safely tolerate a certain dose of radiation. However, the therapy is very focused. It is possible that you can get additional treatments to an already treated area or certainly to an area not yet treated. Ask your radiation oncologist about what dose you can safely receive.
American Cancer Society website. Available at: http://www.cancer.org/docroot/home/index.asp .
National Cancer Institute website. Available at: http://www.cancer.gov/ .
Last reviewed February 2009 by
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © 2007 EBSCO Publishing All rights reserved.