Abstract
More than half of all cancer patients in the United States will receive radiation therapy at some point during their disease course. This information page relates to palliative, rather than curative, radiation therapy.
What Is Radiation Therapy?
This term most often refers to external beam radiation. In external beam radiation, high-energy x-rays are aimed at cancerous tumors in the body. In other types of therapy, radioactive material can be delivered into the body by an intravenous infusion, by insertion of a radioactive implant, or by catheter directing placement of the radioactive material.
What Is Palliative Radiation?
Palliative radiation is radiation that is used to relieve symptoms, often by reducing the size of tumor masses. Radiation can also be used as part of curative therapy for many cancers.
How Is Radiation Delivered?
External beam radiation is delivered with a machine called a linear accelerator, which looks somewhat like an x-ray machine. The patient is usually lying flat on a table, similar to as when one has an x-ray or computed tomography (CT) scan performed. Each treatment itself lasts only a few minutes and is painless. The entire appointment (including positioning and preparation) may last 30 minutes.
Before the first treatment the patient will have a “simulation” session in which the area to be treated is mapped out so that each treatment will be directed at exactly the same location. This involves lying on a table, similar to when having the treatment done, and having measurements made. It may also involve having markings or small tattoos placed at the treatment site.
Systemic radiation can be administered with an intravenous infusion of radioactive material, most often for widespread bone pain. Brachytherapy (treatment with a radioactive implant) is administered by insertion of an applicator during a minor procedure, at times requiring anesthesia or sedation.
How Often Is Radiation Delivered?
Palliative radiation is usually given daily for a period of 5 to 10 days, usually Monday through Friday. Occasionally, palliative radiation may be delivered in a single session or require up to 3 weeks.
How Does Radiation Therapy Work?
Radiation damages the DNA (genetic material) of cells, which may either kill the cell or prevent the cell from further reproducing. Cancer cells as well as normal cells are affected by radiation, but cancer cells have less ability to repair themselves. Because of this, cancer cells are more likely than normal cells to die from radiation damage.
What Problems or Symptoms Are Treated with Palliative Radiation?
Pain: When caused by cancer that has spread to bone or is compressing nerves, internal organs, or other structures
Compression of the spinal cord by cancer
Tumors in the brain, whether metastatic (spread from other parts of the body) or primary (starting in the brain)
Obstruction: When cancer blocks the esophagus (swallowing tube), the trachea or bronchi (breathing tubes), the bile duct system, or large blood vessels
Bleeding: From cancer invading into blood vessels or bleeding from the tumor itself
How Quickly Do Symptoms Improve after Palliative Radiation?
Some symptoms (such as bone pain) may begin to improve within days to weeks. Other symptoms (such as those associated with spinal cord compression) may take longer to improve. Furthermore, radiation may be used along with other treatments (surgery, endoscopy) to relieve symptoms related to spinal cord compression or obstruction of various structures.
What Are the Side Effects of Palliative Radiation?
Radiation itself does not hurt. However, its effects on normal tissue may cause side effects. Most side effects begin after 1 or 2 weeks of treatment, whereas others, such as nausea, may begin with the first treatment. Most side effects will resolve or improve within the first 3 to 6 weeks after treatment is stopped. Side effects are generally milder than with curative radiation and will depend on the area of the body treated:
Skin problems: Redness (similar to a bad sunburn), itching, or dry skin. These side effects may appear with any site of treatment. Skin receives special care during and after radiation. Diarrhea: Can occur when the pelvis, intestines or rectum area are in the radiation path. Nausea/Vomiting: Can occur when the stomach, intestines, or parts of the brain are irradiated. Hair loss: Will only occur on the part of the body being treated. Throat problems: May include throat pain, difficulty swallowing, and sores in the throat. Occurs when the chest or neck is irradiated. Mouth problems: May include sores, dry mouth, and loss of taste. Occurs when the face or neck are irradiated. Fatigue: May occur with treatment of any body area.
Footnotes
The information and recommendations appearing on this page are appropriate in most instances, but are not a substitute for medical diagnosis. For specific information concerning your personal situation or medical condition, JPM suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. Any other print or online reproduction is subject to approval by the publisher: Mary Ann Liebert, Inc. To purchase bulk reprints, call 914-740-2100.