Radiation Therapy for Bone Cancer

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

For most types of bone cancer, the cancer cells are not easily killed by radiation, so high doses are needed. This can damage nearby healthy tissues, including key structures (like nerves and blood vessels) in the area. Because of this, radiation therapy isn't used as a main treatment for most types of bone tumors (although it's often used for Ewing tumors).

The information here focuses on primary bone cancers (cancers that start in bones) that most often are seen in adults. Information on Osteosarcoma, Ewing Tumors (Ewing sarcomas), and Bone Metastasis is covered separately.

Getting external beam radiation therapy

External beam radiation therapy is radiation delivered from outside the body that's focused on the cancer. This is the type of radiation therapy used most often to treat bone cancer.

Before treatment starts, the radiation team takes careful measurements of the area to be treated with imaging tests such as MRI scans to determine the correct angles for aiming the radiation beams and the proper dose of radiation. This planning session is called simulation.

Most often, radiation is given in more than one treatment. Each treatment is much like getting an x-ray, although the dose of radiation is much higher. The treatment is not painful. For each session, you lie on a special table while a machine delivers the radiation from precise angles.

Each treatment lasts only a few minutes, although the setup time – getting you into place for treatment – usually takes longer.

When might radiation therapy be used?

Radiation therapy might be used in different situations:

• After surgery if it’s not clear that all of the cancer was removed (for example, if cancer cells were found in the edges (margins) of the removed tissue). This is done to try to kill any cancer cells that may have been left behind.
• Instead of surgery (possibly along with other treatments) for bone cancers that can’t be removed (resected) completely. It might help control the growth of the tumor, and can also help control symptoms like pain and swelling.

Types of radiation therapy

Because high doses of radiation are needed to kill bone cancer cells, doctors typically use special types of radiation therapy when treating them. These approaches allow them to control the size and strength of the radiation beams so that higher doses get to the tumor and spare the nearby tissues.

Intensity-modulated radiation therapy (IMRT)

With IMRT, a computer program is used to shape and aim radiation beams at the tumor from several different angles, as well as to adjust the strength (intensity) of the beams. This makes it possible to reduce radiation damage to nearby normal tissues while increasing the radiation dose to the cancer.

Stereotactic radiosurgery (SRS)

This technique lets doctors give a large dose of radiation to a small tumor area, usually in one session. Once imaging tests have been done to show the exact location of the tumor, a very thin beam of radiation is focused on the area from many different angles. This is typically done with a radiation source on the end of a computer-controlled robotic arm, which rotates around the person as they lie on a table. 

Sometimes doctors give the radiation in several smaller treatments to deliver the same or slightly higher dose. This is called stereotactic body radiotherapy (SBRT).

Proton-beam radiation therapy

Proton-beam radiation therapy uses protons to kill cancer cells, instead of x-rays or other types of radiation.

Protons are parts of atoms that travel a certain distance before releasing most of their energy, but that cause little damage to the tissues they pass through. This is different from x-rays, which give off the same amount of energy as they pass through normal tissue both before and after reaching the tumor. Doctors can use this property of protons to give higher doses of radiation to the tumor while doing less damage to the normal tissue around it. 

This type of treatment can be helpful in treating tumors in small, intricate areas (such as the base of the skull or the spine), where it's very important to limit the radiation that reaches nearby structures.

Proton beam radiation requires highly specialized equipment, and there are only a limited number of them in the United States at this time. 

Side effects of radiation therapy

Possible side effects of radiation therapy depend on what area of the body is being treated and how much radiation is used.

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 doctor about the possible side effects because there may be ways to relieve some of them.

Depending on where the radiation is given, it can also damage other organs:

• Radiation to the chest wall or lungs can affect lung and heart function.
• Radiation to the jaw area might affect the salivary glands, which could lead to dry mouth and tooth problems.
• Radiation therapy to the spine or skull might affect the nerves in the spinal cord or brain. This could lead to nerve damage, headaches, and trouble thinking, which usually become most serious a year or two after treatment. Radiation to the spine might cause numbness or weakness in part of the body.
• Radiation to the pelvis can damage the bladder or intestines, which can lead to problems with urination or bowel movements. It can also damage reproductive organs, so doctors do their best to protect these organs by shielding them from the radiation or moving them out of the way whenever possible.
• Radiation that includes a joint (a place where two bones come together) might damage the joint, which could result in pain, scarring, and/or limited range of motion.

Another concern with radiation therapy is that it might cause a new cancer to form in the part of the body that was treated. The higher the dose of radiation (and the younger a person is), the more likely this is to occur, but the overall risk is small and should not keep people who need radiation from getting it.