Chondrosarcoma, from the CureRays guide library.

Chondrosarcoma is a cancer that forms in cartilage, the smooth tissue that cushions bones; most grow slowly and are cured by surgery, but they resist ordinary chemo and radiation.

What it is.

Cartilage is the rubbery tissue that caps the ends of bones and forms structures like the ribs and pelvis. Chondrosarcoma starts when cartilage-making cells grow out of control, usually in the pelvis, thigh, shoulder, or base of the skull. Most are low-grade and grow slowly over years; a minority are high-grade and can spread to the lungs. Because the tumor makes its own cartilage matrix, it carries a poor blood supply and is famously resistant to standard chemotherapy and ordinary x-ray radiation, which makes complete surgical removal the single most important goal.

How radiation treats it.

Radiation damages the DNA inside cancer cells so they can no longer divide. Cartilage tumors repair this damage unusually well, so chondrosarcoma needs much higher doses than most cancers — which is exactly why proton and carbon-ion beams are favored. These particle beams deliver a heavy dose to the tumor and then stop, protecting the delicate nerves and spinal cord nearby. Treatment is painless, given as a series of short daily sessions, and leaves no radioactivity in your body.

The ways we can treat it.

Proton beam therapy. Protons stop at a set depth, so a high dose can be packed into a skull-base or spinal tumor while sparing the brainstem, optic nerves, and spinal cord just millimeters away.

Carbon-ion therapy. Carbon ions hit harder than x-rays or protons, damaging even radioresistant cartilage cells; available at a few specialized centers and used for low- and intermediate-grade skull-base tumors.

Advanced photon radiation (IMRT/IGRT). When particles are unavailable, image-guided, intensity-modulated x-ray radiation shapes the dose tightly around the tumor and is used to higher-than-usual doses.

Questions we hear often.

Why can't I just have chemotherapy? Conventional chondrosarcoma doesn't respond to standard chemotherapy because its cartilage matrix shields the cells and they divide slowly. Surgery — and radiation when surgery can't get it all — is what controls it.

Why do I need proton or carbon-ion radiation instead of regular radiation? Chondrosarcoma needs very high radiation doses, and many tumors sit beside the brainstem or spinal cord. Particle beams stop after the tumor, letting your team push the dose high while protecting those critical structures.

Will it come back? Low-grade tumors removed completely have an excellent outlook. Higher-grade and skull-base tumors need long-term follow-up scans, because chondrosarcoma can return or reach the lungs years later.

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