Radiation therapy is a treatment for cancer that uses strong X-rays. A machine directs the rays of energy to the area of cancer. Radiation therapy is also called radiotherapy. Its goal is to kill or shrink cancer cells.

Radiation therapy is usually not used for people with CLL. But it may be used in certain cases. Your  healthcare provider may suggest radiation therapy for these reasons:

• You need radiation to help manage symptoms. For example, you may have a swollen spleen pressing against another organ, such as your stomach. This can make it hard for you to eat. In this case, radiation can be used to reduce swelling in the spleen and ease the pressure on your stomach.

• You need radiation to help with bone pain. The pain is caused by growth of leukemia cells in bone marrow.

• You need radiation to help get ready for a bone marrow transplant. This is rarely done for CLL, but it may be used in certain cases. Radiation therapy kills not only leukemia cells, but also normal bone marrow cells. This helps prevent rejection of transplanted stem cells. If you need to have a transplant, you may have total body irradiation. This sends radiation in equal doses to all parts of your body.

A healthcare provider who specializes in cancer and radiation is called a radiation oncologist. This provider will work with you to decide what kind of radiation you need. He or she will also determine the dose of and how long you need to get radiation.

Radiation treatments are not painful. They are a lot like getting a chest or dental X-ray. You can have the treatments either as an outpatient or as an inpatient. Outpatient means you go home the same day. Inpatient means you stay overnight in the hospital. If you're having treatment aimed at just a small part of your body, you'll likely do this as an outpatient. If you're preparing for a stem cell transplant, you will have the treatments as an inpatient.

Radiation therapy can kill cancer cells, but it can also damage nearby normal cells. This can lead to side effects. But many people have no side effects. If you do have side effects, they get better and go away over time when treatment ends.

The side effects from radiation therapy depend on where the radiation is aimed, and can include:

• Skin irritation in the area being treated

• Feeling tired (fatigue)

• Nausea, vomiting, and diarrhea, from radiation to the abdomen

Radiation can also lower your blood counts. So your healthcare provider will watch your blood counts closely.

Tell your healthcare provider if you have side effects. You may be given medicine to help prevent and lessen any side effects.

Talk with your healthcare providers about what symptoms to watch for, and when you should call them. Make sure you know what number to call with questions, even on evenings and weekends.

It may be helpful to keep a diary of your side effects. Write down any changes you notice, how severe they are, and when they happen. A written list can make it easier for you to remember your questions when you go to your next appointment. It can also make it easier for you to work with your medical team to make a plan to manage your side effects.