Chordoma, from the CureRays guide library.

Chordoma is a rare, slow-growing bone cancer of the spine and skull base; surgery and high-dose particle radiation are the cornerstones of treatment.

What it is.

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.

How radiation treats it.

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 ways we can treat it.

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.

Questions we hear often.

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.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.