Doctors may recommend radiation therapy to treat many different types of blood cancer. Radiation therapy can help kill cancer cells and reduce symptoms of leukemia. This type of treatment is also known as radiotherapy or irradiation.

What Is Radiation Therapy?

Radiation therapy uses high-energy particles or beams to kill cancer cells. You can’t see or feel these particles, but radiation harms a cell’s DNA. When DNA becomes too damaged, the cell can no longer grow and make new copies of itself.

Goals of Radiation Therapy for Leukemia

Radiation therapy is usually used to kill cancer cells along with other leukemia treatments, such as chemotherapy or targeted therapy. Radiation only works where it is focused, whereas chemotherapy works everywhere that it can reach through the blood. Chemotherapy and targeted therapy medications are often better at killing leukemia cells, so radiation is generally not one of the main treatments for leukemia. However, radiation therapy can also be useful in other ways.

Stem Cell Transplantation

Radiation therapy or high-dose chemotherapy is the first step for a stem cell transplant. This procedure, also known as a bone marrow transplant, is often one of the only treatment options that can cure leukemia. Stem cell transplantation replaces a person’s stem cells, the cells that make new blood cells. Stem cells generally live in the bone marrow (tissue found inside certain bones) but may be crowded out by leukemia cells. People undergoing stem cell transplantation first receive aggressive radiation or chemotherapy, which has a few purposes:

• It kills cancer cells located throughout your body.
• It kills your stem cells and makes room in the bone marrow for new stem cells to come in.
• It reduces the chances that the immune system will reject new stem cells, helping prevent a serious side effect called graft-versus-host disease.

After undergoing aggressive treatment, a person with leukemia receives healthy stem cells from a donor (in allogeneic stem cell transplantation) or receives their own stem cells that were previously removed (in autologous stem cell transplantation).

Reducing Symptoms of Leukemia

Doctors may also recommend radiation treatments for certain signs of leukemia, including:

• Splenomegaly (enlarged spleen)
• Hepatomegaly (enlarged liver)
• Lymphadenopathy (swollen lymph nodes)

Enlarged organs can cause pain and discomfort. They are typically first treated with drugs like chemotherapy. If these treatments don’t work, then radiation may help by shrinking the organs. Radiation treatments that are used to relieve symptoms and provide a better quality of life are known as palliative therapy.

Radiation Therapy for Different Types of Leukemia

Doctors may aim for different treatment goals depending on which type of leukemia a person has. Acute and chronic leukemias may be treated with radiation in slightly different ways.

Acute Leukemias

Acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) are occasionally treated with radiation. Radiotherapy may be recommended as a part of a stem cell transplant. It may also be used to reduce the number of leukemia cells inside the bone marrow if other medications aren’t working. Radiation treatments can also be effective for killing leukemia cells that have spread to other parts of the body, such as the central nervous system (brain and spinal cord) or the testicles.

Acute leukemias may cause tumors in the chest or neck. These tumors can press on the windpipe and make it difficult to breathe. On rare occasions, radiation treatments may be used to treat these tumors, although chemotherapy is normally used instead.

Chronic Leukemias

Radiation treatments are not often used for people with chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML). Radiotherapy may be recommended in certain situations:

• To shrink the spleen or other organs
• To treat bone pain if there are too many leukemia cells in the bone marrow
• To prepare the body for a stem cell transplant

Types of Radiation Therapy

There are two main forms of radiotherapy. External beam radiation uses a machine to direct a beam of radiation toward a particular part of the body. Internal radiation therapy, also called brachytherapy, is a treatment in which a radioactive substance is put inside the body.

Doctors recommend specific radiation treatments based on a person’s type of cancer, age, overall health, and what other cancer treatments they are receiving.

External Beam Radiation Therapy

The most common type of radiation therapy used to treat leukemia is external beam radiation. It is generally used as a local treatment, which means that only a specific part of the body is exposed to radiation.

There are two types of external beam radiation used to treat leukemia. Most often, this treatment uses photon beams (streams of light particles). This is the same type of radiation used during X-rays, but it is stronger. Another form of external beam radiation uses streams of protons (charged particles) in a procedure called proton beam therapy or proton radiotherapy. Proton beam therapy is more precise but less available — it can be better controlled, leading to less damage to healthy cells and a lower risk of side effects.

When external beam radiation is used before a stem cell transplant, it is called total body irradiation (TBI). In TBI, the entire body is treated with radiation.

Internal Radiation Therapy

Doctors put radioactive material inside your body during internal radiation therapy. If the radioactive material is placed inside of a solid substance, such as seeds, tubes, or capsules, it is called brachytherapy or implant radiation therapy. Brachytherapy is also a local treatment — the radiation only affects nearby tissues.

Liquids can also be used to carry radioactive particles to cancer. Taken this way, internal radiation therapy is a form of systemic therapy, meaning that the radioactive substance reaches the bloodstream and travels throughout the whole body. This type of treatment is given through an injection, delivered in an intravenous (IV) line, or taken by mouth.

Radioimmunotherapy drugs are a type of systemic internal radiation therapy. These medications include a radioactive substance attached to a monoclonal antibody. The antibody is a molecule that can find and attach to specific proteins found on cancer cells. Radioimmunotherapies, such as Zevalin (ibritumomab), are sometimes used to treat people with lymphocytic leukemia (CLL or ALL).

External Beam Therapy: What To Expect

Radiation treatments are overseen by a doctor called a radiation oncologist, who helps determine the types of radiation therapy and doses that will work best for you. The treatments may be administered by a team that also includes oncology nurses and radiation therapists.

Preparing for External Beam Radiation Therapy

External beam therapy is usually given throughout several sessions, and the radiation needs to be delivered to the same spot each time. Your radiation oncologist calculates where to aim the beams of radiation using a simulation.

A simulation involves planning out how your body will be positioned while receiving treatment. This is accomplished using imaging tests such as a computed tomography (CT) scan or magnetic resonance imaging (MRI). Your radiation team can use these tests to calculate the location and dose of the radiation you will receive. Radiation therapists may mark your skin with a special ink that lasts for a long time. These marks are used to position the external beam treatments during each treatment session. Depending on the locations, shields will be made and specifically adjusted to your body to protect nearby organs from radiation.

Receiving External Beam Treatments

During each visit for external beam therapy, you will change into a gown and be taken to a separate treatment area. X-rays and CT scans may be used to help you get into the correct position. You will stay in the same place as the radiation machine moves around you.

You will only be exposed to radiation for a few minutes at a time. During these times, you need to stay still, which can be uncomfortable. However, the radiation itself doesn’t hurt. In between each radiation exposure, you may need to change positions. In total, you may be in the treatment area for just a few minutes or 20 to 30 minutes.

External beam radiation treatments are typically given throughout several visits. People often receive radiation treatments five days per week. Leukemia treatments typically last between two to 10 weeks. If you are receiving TBI, you will usually undergo two treatments per day for up to four days.

Side Effects

Radiation damages all cells, whether they are cancerous or healthy. Doctors can limit the damage done to the body’s normal cells, but some healthy cells will still be harmed, leading to side effects. Common side effects of radiation therapy are fatigue, diarrhea, hair loss, and skin changes. Other side effects may vary based on the location that is being irradiated:

• Radiation treatments in the abdomen may cause diarrhea, nausea, vomiting, and urination changes.
• Radiotherapy in the chest area may lead to swallowing difficulties, shortness of breath, and coughing.
• Radiation treatments for the brain can cause nausea, vomiting, headaches, and blurry vision.

Taking care of yourself after radiation treatments can help lessen side effects. It’s important to get enough sleep and to eat a healthy diet. Additionally, your doctor should explain how to take care of your skin following external beam therapy. Bathing in warm water, limiting sun exposure, and wearing loose clothes can help the skin heal.

Side effects often go away a few months after you finish radiation treatments. Occasionally, some people have lasting effects or have long-term effects that appear many months or years later. These effects may vary based on the location of the radiation treatments. Some long-term side effects of radiation of the bones include bone loss and trouble moving the joints. Radiation of the brain may eventually cause memory loss, personality changes, and movement problems in some people.

Radioimmunotherapy: What To Expect

Before you begin radioimmunotherapy treatments, you will take iodide pills that protect your thyroid gland from radiation. You will usually first receive a dose of the antibody drug alone and then receive treatment that combines the antibody with a radioactive substance.

This type of treatment may take some time to work. After you receive this treatment, you need to have regular follow-up visits so that your doctor can check your progress using exams and tests.

Radioimmunotherapy drugs may lead to mild side effects. These treatments often lead to low levels of blood cells temporarily. Radioimmunotherapies can also cause diarrhea, low blood pressure, and a rash. Most people feel normal quickly after finishing this treatment.

If you receive internal radiation therapy, you will give off radiation after receiving treatment. Your sweat, saliva, and urine will be radioactive. You should stay away from children or people who are pregnant. Your doctor may also give you additional instructions to protect the people around you, such as using separate towels and utensils.

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