Radiation therapy, also called radiotherapy or irradiation, can be used to treat leukemia, lymphoma, myeloma and myelodysplastic syndromes. 

Radiotherapy works by damaging the genetic material (DNA) within cells, which prevents them from growing and reproducing. Although the radiotherapy is directed at cancer cells, it can also damage nearby healthy cells. However, current methods of radiotherapy have been improved upon, minimizing “scatter” to nearby tissues. Therefore its benefit (destroying the cancer cells) outweighs its risk (harming healthy cells).

When radiotherapy is used for blood cancer treatment, it's usually part of a treatment plan that includes drug therapy. Radiotherapy can also be used to relieve pain or discomfort caused by an enlarged liver, lymph node(s) or spleen.

Radiotherapy, either alone or with chemotherapy, is sometimes given as conditioning treatment to prepare a patient for a blood or marrow stem cell transplant. The most common types used to treat blood cancer are external beam radiation (see below) and radioimmunotherapy.

 
External Beam Radiation

External beam radiation is the type of radiotherapy used most often for people with blood cancers. A focused radiation beam is delivered outside the body by a machine. The machine moves around the body to deliver radiation from various angles. 

Most radiation therapy machines use photon beams from a machine called a linear accelerator, or linac for short. The same type of radiation is used for x-rays, but x-rays use lower doses. This is the most common type of external beam radiation. 

At some cancer centers, proton beam radiation may be an option. Protons are particles with a positive charge. Proton beam radiation can be more targeted than photon beam radiation. This helps to minimize damage to healthy tissues and organs and may decrease the risk of long-term and late effects. This type of radiation therapy is newer and requires a special machine. 

The dose (total amount) of radiation used during treatment depends on various factors regarding the patient, disease and reason for treatment, and is established by a radiation oncologist. You may receive radiotherapy during a series of visits, spread over several weeks (from two to 10 weeks, on average). This approach, called dose fractionation, lessens side effects. External beam radiation does not make you radioactive.

Before Treatment

You'll need to prepare for radiotherapy by undergoing a "simulation" so the technician can determine the most effective ways to direct the radiation and position you during treatment.

For the simulation, members of the radiation oncology team measure your body and sometimes mark your skin to ensure the radiation is aimed at the same part of your body during each treatment session. These marks are small dots usually made with semipermanent ink. You can choose to have the marks removed (by surgery or laser treatment) after radiotherapy is completed. However, some doctors encourage patients to keep the marks to show the exact site(s) of initial therapy if additional radiotherapy is needed in the future. Instead of marking the skin, a radiation therapist may mark an immobilization device — a mold, cast or similar object — used to help you remain still during the treatment sessions.

During Treatment

You shouldn't feel any pain or discomfort during an external beam radiation treatment session. However, you may need to stay in one position for several minutes during a session, which is uncomfortable for some patients. Shields protect certain parts of your body, such as the testes or ovaries, from radiation. You'll likely spend 20 to 30 minutes in the treatment area even though actual radiation exposure lasts only a few minutes.

When you receive the radiation, the treatment team leaves the room and stands behind a protective barrier to protect them from repeated exposure. They can still hear you and see you through a window or closed-circuit television camera. You can talk to them during the treatment and report any discomfort or special needs.

In between sessions, let your treatment team know about any discomfort you experience so they can make changes if needed.

After Treatment

During and after radiotherapy, you need to get plenty of rest and follow a nutritious diet. Eating well during and after cancer therapy can help you cope with side effects, fight infection, rebuild healthy tissue and maintain body weight and energy. Above all, a nutritious diet combined with regular exercise promotes overall wellness.

Follow your doctor's advice about caring for skin exposed to radiation. To help damaged skin heal:

• Shower or bathe with warm water
• Protect the damaged area from the sun
• Wear loose clothes
• Get medical guidance before using skincare products on the affected area(s)

To cope with side effects such as fatigue, seek support from healthcare professionals and other patients who've had similar treatment.

Helpful Resources

• OncoLink, "Radiation Oncology" - An overview of radiotherapy. The site also features information about different types of cancer, treatment options and research advances.
• National Cancer Institute, "Radiation Therapy and You: Support for People with Cancer" - Helpful information about radiotherapy and all aspects of cancer.
• RT Answers - The patient website of the American Society for Radiation Oncology (ASTRO) features information about radiotherapy and cancer.
• The Society of Nuclear Medicine (SNM) - Includes patient information about molecular imaging, radiation safety and procedures such as PET scan.
• White Paper on Radiation Dose in Medicine - Download this white paper from the American College of Radiology.