Radiation therapy for childhood bone cancer

Radiation therapy uses high-energy rays or particles to destroy cancer cells.

Radiation therapy is sometimes used to treat childhood Ewing sarcoma. It is rarely used to treat childhood osteosarcoma. The healthcare team will use what they know about the cancer and about your childʼs health to plan the type and amount of radiation, and when and how it is given.

Radiation therapy may be used to:

• shrink a tumour before surgery (called neoadjuvant therapy)
• destroy cancer cells left behind after surgery or chemotherapy to reduce the risk that cancer will come back (called adjuvant therapy)
• treat a Ewing sarcoma that canʼt be removed with surgery
• treat a recurrence
• relieve pain or control the symptoms of advanced Ewing sarcoma (called palliative therapy)

External radiation therapy is the type of radiation therapy used to treat Ewing sarcoma.

During external radiation therapy, a machine directs radiation through the skin to the tumour and some of the tissue around it. External radiation therapy is also called external beam radiation therapy. Doctors may use the following external radiation techniques to accurately target the area to be treated and spare as much surrounding normal tissue as possible.

Intensity-modulated radiation therapy (IMRT) delivers radiation from many different angles to treat the entire tumour. In addition to shaping and aiming the radiation beams, IMRT allows the radiation oncologist to adjust the intensity of the individual beams. This reduces the dose of radiation reaching nearby normal tissue while allowing a higher dose to be delivered to the tumour and reducing side effects. It’s useful for treating tumours in hard-to-reach areas such as the spine or pelvis.

Stereotactic radiosurgery gives very high doses of radiation to a very specific area where cancer is found. It is given in a small number of sessions. It may be used to treat Ewing sarcoma that has spread to other bones or to the lungs. Stereotactic radiosurgery may be available in some hospitals in Canada.

Proton therapy uses proton beams instead of x-ray beams to treat cancer. It may also be called proton beam therapy. Protons release more energy after reaching a certain distance and then stop, while x-ray beams release energy before and after they hit their target. So protons cause less damage to tissues surrounding the target. Machines called synchrotrons or cyclotrons produce the protons. These machines are not available at any hospitals and cancer centres in Canada. Children who need this treatment must go to treatment centres in the US.

During radiation therapy, the healthcare team protects healthy cells in the treatment area as much as possible. Side effects of radiation therapy will depend mainly on the size of the area being treated, the specific area or organs being treated, the total dose of radiation and the treatment schedule.

Tell the healthcare team if you think your child has any side effects from radiation therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help your child deal with them.

The most common side effects of radiation therapy used for childhood bone cancer are:

• fatigue
• skin problems
• hair loss
• low blood cell counts
• nausea and vomiting
• loss of appetite
• diarrhea
• radiation enteritis

Other side effects can develop months or years after radiation therapy for childhood bone cancer. These are called late effects. Find out more about the late effects of treatment for childhood bone cancer.

Find out more about radiation therapy and the side effects of radiation therapy. To make the decisions that are right for your child, ask the healthcare team questions about radiation therapy.