The purpose of radiation therapy is to kill or stop the growth of tumor cells within the body. Radiation can serve different roles in the treatment of chordoma, which can vary based on the stage of the disease.
Read more about radiation for newly diagnosed skull base tumors
Chordomas are generally treated with a beam of radiation that is delivered to the tumor from a source outside of the body. This is called external beam radiation.
Radiation with beams of charged particles, called particle therapy, is generally recommended for treating chordoma because it can be focused very precisely on the tumor.
Two different types of particles are commonly used: protons and carbon ions. These are usually referred to as proton therapy or proton beam therapy, and carbon ion therapy. It is not yet known whether there is any difference in effectiveness between protons and carbon ions.
Proton and carbon ion treatment centers are very expensive to build, so they do not exist at every medical institution. Proton centers are becoming more common, with centers in the United states and several countries throughout Europe and Asia. Currently, carbon ion therapy is only available in Austria, China, Germany, Italy, and Japan.
In some cases, highly focused photon radiation can be a suitable alternative to particle therapy as long as a high enough dose can be delivered without damaging healthy tissue. Intensity modulated radiation therapy (IMRT) is one type of photon radiation that may be used.
Stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) are types of hypofractionated radiation, which may make them important options for recurrent or advanced chordoma. When hypofractionation is used the total amount of radiation given is less than when standard fractionation is used, but the effect should be the same.
Sometimes it may be helpful to combine particle therapy and photon radiation. For all types of external beam radiation, imaging is needed every day of treatment to make sure that the radiation is going to exactly the right place. This technique is called image guidance.
Another method of delivering radiation, called brachytherapy, involves inserting a small amount of radioactive material inside the body during surgery. This method is not used very often for chordoma, but can sometimes be helpful for delivering a high enough dose of radiation to the area near the brainstem or spinal cord. When used, it is usually given in combination with external beam radiation.
What matters most about radiation for chordoma is that chordomas require very high doses of radiation to be controlled. Specifically, a total dose of at least 74 GyE (Grey Equivalents) is recommended for proton and photon radiation. If the entire tumor has been removed, the dose of radiation to the areas surrounding where the tumor was can sometimes be limited to 70 GyE. See the treatment guidelines for new diagnosis for more information.
Once you have been treated with a high dose of radiation, it might not be possible for you to have radiation again. If your tumor comes back after your first treatments, the option of further radiation will depend on factors such as the location of the new tumor growth and how long it has been since the previous dose of radiation. Hypofractionated radiation like SRS and SBRT can sometimes make it possible to have further radiation.
Lower doses of radiation are sometimes given to help slow the growth of recurrent or advanced tumors and ease symptoms like pain and nerve damage. Radiation may also be given along with drug therapies to help increase their effectiveness.
Any time you are considering treatment it is a good idea to talk with your medical team about the role that radiation therapy should play in your treatment.
Before you begin radiation treatments, you will visit with the radiation oncologist. The doctor will discuss your treatment plan with you, including what side effects you might expect from the treatments. If you have a skull base or cervical tumor, radiation technicians will fit you for a mask that will be used to stabilize your head and neck during the treatments. Something similar may also be done if your tumor is on the thoracic, lumbar, or sacral spine.
The radiation technicians will see you at each visit. You may need to remove certain parts of clothing and then the tech will have you lay down on a special table, called a treatment couch, which is used to accurately position you. If you have a mask, the technician will attach your mask to the treatment couch. This can cause some patients to feel anxious or claustrophobic. If this happens to you, ask your technicians about things other patients have found helpful in dealing with this feeling.
Proton beam, carbon ion, and IMRT photon radiation are typically given in small doses during daily sessions (usually around 35-40) over 6-8 weeks. The dose of radiation delivered during each session is called a fraction. The radiation from each fraction accumulates over time until the total dose is reached. The treatments themselves last just a minute or two.
Hypofractionated radiation like SRS and SBRT are given in larger doses over a shorter amount of time (usually 1-5 sessions). This is called hypofractionation. The treatments themselves can last an hour or more, depending on how many sessions are being done.
During treatment, you will have a check-up with your radiation oncologist every few weeks. After you complete all radiation treatments, your doctors will likely recommend waiting 2-3 months before doing imaging to allow time for any swelling or inflammation that might have been caused by the treatments to subside.
The amount of radiation required to treat chordoma is higher than what healthy tissue can handle. For this reason, it is important for the radiation dose to be focused on the tumor while avoiding important nearby structures such as the brain, brainstem, nerves, or spinal cord. However, even with highly focused radiation like proton beam or carbon ion therapy, short- and long-term side effects are still possible.
Short-term side effects that you might experience during radiation treatments can vary depending on the location of your tumor. A rash and skin irritation at the site of radiation are very common for all patients. Your care team can suggest types of lotion or cream that can help protect your skin and soothe irritation. Nausea and fatigue are experienced by most patients at some point during radiation treatments. Other side effects that might be experienced are listed below.
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Despite these possible side effects, most patients receiving radiation say they feel good enough to continue daily activities. Patients having proton beam therapy who move temporarily to where the proton center is located often enjoy outings and sightseeing in the local area.
Most of these side effects will resolve after radiation ends. However, some can remain for many months or be permanent. You may also experience “late” effects of radiation, meaning they do not begin until months or years after radiation ends.These can include issues with endocrine system function; changes to hearing, vision, or swallowing; bowel, bladder, or sexual issues; and neuropathy including pain, weakness, and numbness in the face or extremities.
Talk with your radiation oncologist about the risks involved in your radiation treatment plan.
Learn from chordoma experts about the types of radiation used to treat chordoma
The resources and information below can help you make the most informed decisions about your treatment.
The information provided herein is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your or your child’s physician about any questions you have regarding your or your loved one’s medical care. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.