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What is chordoma?
Chordoma is a rare, slow-growing cancer that develops in the bones of the spine and the base of the skull. It arises from leftover cells of the notochord, a structure present before birth that helps form the spine; tiny remnants of these cells can later give rise to a chordoma. The most common locations are the very bottom of the spine (the sacrum and tailbone area), the base of the skull, and the bones of the spine in between. Because chordomas grow in these delicate places — near the brainstem, spinal cord, important nerves, and blood vessels — they can be challenging to remove completely, and they tend to come back locally if any tumor is left behind. Symptoms depend on location and can include pain, numbness or weakness, problems with bladder or bowel control, or, for skull base tumors, double vision and headaches. Chordoma is treated by a highly specialized team. The cornerstones of care are careful surgery to remove as much tumor as safely possible, followed by high-dose, precisely targeted radiation — often using proton or other particle beams — to control any remaining cells.
The main types
Doctors group chordoma by where it starts and how it behaves:
| Type | What it means, simply |
|---|---|
| Conventional chordoma | The most common type, made of classic notochord-like cells; slow-growing but persistent. |
| Chondroid chordoma | A subtype with cartilage-like features, more often found at the skull base; tends to behave somewhat more favorably. |
| Dedifferentiated chordoma | A rare, faster-growing and more aggressive form that needs more intensive treatment. |
Staging, in plain terms
Chordoma is not usually described by standard number stages. What matters most is where the tumor is (skull base, mobile spine, or sacrum), how large it is, how much it involves nearby nerves, the spinal cord or brainstem, and blood vessels, and whether it can be removed completely with clear margins. Because chordoma rarely spreads to distant organs but often regrows where it started, controlling the tumor at its original site is the central goal. Doctors use detailed MRI and CT imaging to map the tumor and plan surgery and radiation together.
| Location and resectability based (not standard TNM) | What it generally means |
|---|---|
| Localized, fully removable | The tumor can be removed completely with a margin of healthy tissue — the best situation, usually followed by radiation to lower the chance of return. |
| Localized, partly removable | The tumor is wrapped around critical nerves or structures, so some must be left behind — high-dose radiation is used to control the remaining tumor. |
| Recurrent | Chordoma that has grown back at the original site — managed with further surgery, radiation, and clinical trials. |
| Metastatic | Uncommon spread to distant sites such as the lungs or other bones — managed with radiation, surgery when helpful, and trials of targeted medicine. |
The standard of care
Chordoma is almost always treated by a team that may include a surgeon, a medical oncologist, and a radiation oncologist, combining therapies for the best result. The usual building blocks are:
Surgery
Removing as much of the tumor as safely possible — ideally in one piece with clear margins — is the foundation of treatment, done by surgeons experienced with the spine and skull base.
High-dose particle radiation
Chordomas need a very high radiation dose to control them, which is best delivered with proton or other particle beams that can concentrate dose on the tumor while sparing the spinal cord and brainstem.
Targeted medicine (selected cases)
For tumors that grow back or spread, certain targeted drugs are used or studied, since standard chemotherapy is not very effective for chordoma.
Long-term monitoring
Because chordoma can return years later, regular imaging follow-up is an important part of care.
How radiation treatment works
Radiation uses high-energy beams to damage the DNA inside tumor cells so they can no longer grow and divide. Chordomas are relatively resistant to radiation, which means they require a very high dose to control — higher than nearby structures like the spinal cord and brainstem can normally tolerate. This is why chordoma is one of the clearest examples where the type of radiation matters. Proton beams and heavy-particle beams (such as carbon ions) can be aimed to release most of their energy right at the tumor and then stop, delivering a powerful dose to the cancer while protecting the critical nerves and tissues just millimeters away. Radiation is usually given after surgery to destroy any tumor cells left behind, and it can be the main treatment when a tumor cannot be safely removed. Treatments are painless and delivered over a series of carefully planned sessions by a highly specialized team. Side effects depend on the location treated and are managed closely.
The main ways radiation is delivered for chordoma:
Proton therapy
Proton beams stop at a set depth, delivering a high dose to the tumor while sharply limiting dose to the spinal cord, brainstem, and other vital structures nearby.
Carbon-ion / heavy-particle therapy
Available at specialized centers, heavy-particle beams deliver very powerful, focused radiation to chordomas that are otherwise hard to control.
Stereotactic radiosurgery / SBRT
Highly focused photon radiation delivered in one or a few sessions can treat selected tumors or areas of regrowth with great precision.
Post-surgery (adjuvant) radiation
High-dose radiation after surgery targets any microscopic tumor left behind to lower the chance of the cancer returning at the original site.
Latest studies shaping care
Care keeps improving — often toward getting the same excellent results with less burden on patients. A few developments:
High-dose proton therapy improves control: Studies of skull base and spine chordoma show that combining surgery with high-dose proton therapy achieves better long-term local control than lower-dose conventional radiation.[1]
Skull base and spinal chordoma proton series
Carbon-ion therapy for difficult tumors: Specialized centers report strong local control with carbon-ion radiation for chordomas that are hard to remove or have returned, expanding options for these challenging tumors.[2]
International particle therapy registries
Targeted and immune therapies under study: Because standard chemotherapy is not effective, researchers are testing targeted drugs and immune therapies, including approaches aimed at a protein called brachyury that drives chordoma.[3]
Chordoma Foundation–supported trials
Common questions
Why is special radiation used for chordoma? Chordomas need a very high radiation dose to control, but they sit right next to the spinal cord and brainstem, which can only tolerate so much. Proton and particle beams can deliver that high dose to the tumor while stopping short of these vital structures, making treatment both powerful and safe.
Will chordoma come back? Chordoma rarely spreads to distant organs, but it can return at the original site, sometimes years later. That is why complete surgery, high-dose radiation, and long-term imaging follow-up are all important parts of care.
Is chemotherapy used? Standard chemotherapy is not very effective against chordoma, so it is not a main treatment. For tumors that grow back or spread, doctors may use or study targeted medicines and immune therapies, often through clinical trials.
References
Numbered sources for the studies cited above. Links open the primary publication on PubMed or the publisher’s site.