Radiation therapy for osteosarcoma
Radiation therapy uses high-energy rays or particles to kill cancer cells. Osteosarcoma cells are not easily killed by radiation, so radiation therapy does not play a major role in treating this disease.
External beam radiation therapy
This is the type of radiation therapy most often used to treat osteosarcoma.
Before treatments start, the radiation team takes careful measurements with imaging tests such as MRI scans to determine the correct angles for aiming the radiation beams and the proper dose of radiation.
External radiation therapy is much like getting an x-ray, although the dose of radiation is much higher. For each session, you (or your child) will lie on a special table while a machine delivers the radiation from a precise angle. The treatment is not painful.
Each actual treatment lasts only a few minutes, although the setup time – getting you (or your child) into place for treatment – usually takes longer. Young children may be given medicine to make them fall asleep so they will not move during the treatment. Most often, radiation treatments are given 5 days a week for several weeks.
Newer radiation techniques, such as intensity modulated radiation therapy (IMRT) and conformal proton beam therapy, may allow doctors to aim treatment at the tumor more precisely while reducing how much radiation nearby healthy tissues get. This may offer a better chance of increasing the success rate and reducing side effects. Many doctors now recommend using these approaches when they are available (see “What’s new in osteosarcoma research and treatment?”).
Radiation therapy may be useful in some cases where the tumor cannot be completely removed by surgery. For example, osteosarcoma can start in hip bones or in the bones of the face, particularly the jaw. In these situations, it is often not possible to completely remove the cancer. As much as possible is removed, and then radiation is given to try to kill the remaining cancer. Chemotherapy may be used after radiation.
Radiation can also help control symptoms like pain and swelling if the cancer has come back or surgery is not possible.
The possible side effects of external radiation therapy depend on the dose of radiation and where it is aimed. Short-term problems can include effects on skin areas that receive radiation, which can range from mild sunburn-like changes and hair loss to more severe skin reactions. Radiation to the abdomen or pelvis can cause nausea, diarrhea, and urinary problems. Talk with your (child’s) doctor about the possible side effects because there may be ways to relieve some of them.
In children, radiation therapy can interfere with the growth of normal body tissues, including the bones. For example, radiation to the bones in one leg might result in it being much shorter than the other. Radiotherapy of facial bones may cause uneven growth, which might affect how a child looks. But if a child is fully or almost fully grown, this is less likely to be an issue.
Depending on where the radiation is aimed, it can also damage other organs. Radiation to the chest wall or lungs may affect lung and heart function. Radiation to the pelvis may damage the bladder or intestines. It can also damage reproductive organs, which could affect a child’s fertility later in life, so doctors do their best to protect these organs by shielding them from the radiation or moving them out of the way whenever possible.
Another major concern with radiation therapy is that it may cause a new cancer to form in the part of the body that was treated with the radiation. The higher the dose of radiation, the more likely this is to occur, but the overall risk is small and should not keep children who need radiation from getting treatment.
To lower the risk of serious long-term effects from radiation, doctors try to use the lowest dose of radiation therapy that is still effective. Still, it’s important to continue follow-up visits with your (child’s) doctor so that if problems come up they can be found and treated as early as possible.
Radioactive drugs (radiopharmaceuticals)
Bone-seeking radioactive drugs, such as samarium-153, are also sometimes used to treat symptoms such as pain in people with advanced osteosarcoma. These drugs are injected into a vein and collect in bones. Once there, the radiation they give off kills the cancer cells and relieves some of the pain caused by bone metastases.
These drugs are especially helpful when cancer has spread to many bones, since external beam radiation would need to be aimed at each affected bone. In some cases, these drugs are used together with external beam radiation aimed at the most painful bone metastases.
The major side effect of these drugs is a lowering of blood cell counts, which could increase the risk for infections or bleeding, especially if the blood counts are already low.
For more detailed information on radiation therapy, see Understanding Radiation Therapy: A Guide for Patients and Families.
Last Medical Review: 01/08/2013
Last Revised: 01/17/2013