Radiation therapy uses X-rays or another source to kill cancer cells. It is rarely used to treat chronic myeloid leukemia (CML). It may be used to ease symptoms, such as pain or pressure on organs. In some cases it may be given in low doses to the whole body just before a stem cell transplant.
Radiation therapy is not common for CML. Your doctor may recommend it for these reasons:
Your symptoms aren't responding to other treatments. For instance, you may have a swollen spleen pressing against another organ, such as your stomach. This can cause a lack of appetite. In this case, radiation can be used to reduce swelling if it is not responding to other therapies. Radiation can also help with bone pain caused by the leukemia spreading to the bone.
Leukemia cells have spread to your brain or spine. Radiation can provide a concentrated attack on the leukemia cells in those parts of your body.
You have decided to have a stem cell transplant. Radiation therapy kills not only cancer cells, but also normal bone marrow cells. If you need to have a transplant, you may receive total body irradiation (TBI). This distributes radiation in equal doses to all parts of your body. That's because leukemia cells can be in any blood vessel in any part of your body. If, for some reason, you can't undergo TBI, you may be able to take drugs that will accomplish the same goal. In fact, most stem cell transplants for CML today are done without the use of radiation. Talk about these options with your doctor.
When radiation therapy is used to treat CML, you get radiation directed at you from a machine. This is called external radiation.
A doctor who specializes in cancer and radiation is called a radiation oncologist. This doctor will work with you to determine what kind of radiation you need. This doctor will also determine the dose and how long you need the therapy.
At the start of the treatment session, you'll lie on a table while the machine is placed over you. You may have to wear a hospital gown. The experience is much like that of getting an X-ray, only longer. A radiation therapist may place blocks or special shields to protect parts of your body that don't need to be exposed to radiation. The therapist will then line up the machine. When you are ready, the therapist will leave the room and turn the machine on. You may hear whirring or clicking noises while the radiation is being given. During the session, you will be able to talk to the therapist over an intercom. You can't feel radiation, so the process will be painless. You may need to be in the radiation room for 20 minutes to 30 minutes for each treatment, but you are exposed to radiation for only a few minutes. You will not be radioactive afterward.
Because radiation affects normal cells as well as leukemia cells, you may have some side effects from this treatment. Their severity depends on the dose, frequency, and location of the treatments. Many people have no side effects at all. If you do have them, your doctor may change the dose of your radiation, or the doctor may stop treatment until the side effects are cleared up. Be sure you keep your doctor informed about the side effects you have. If you are having radiation directed to a specific part of your body, the side effects are usually mild. Generally, side effects get better and go away when the treatment ends.
The side effects depend in part on what area of your body is being irradiated. These are short-term side effects you may experience:
Diarrhea if your abdomen is being treated
Nausea and vomiting
Sore mouth (called mucositis)
Decreased blood counts
Easy bruising and bleeding
Long-term side effects of radiation may not show up for several years after your treatments end. Here are some possible long-term side effects:
Chronic skin changes (for example, a reappearance of redness after exposure to other agents, such as chemotherapy)
The immediate side effects of total body irradiation can be more severe than for targeted radiation. They include an increased risk for infection from a reduction in white blood cells and from damaged skin and mucous membranes.