Osteosarcoma (Bone Cancer), from the CureRays guide library.

Osteosarcoma is the most common bone cancer, often in teenagers and young adults; chemotherapy and surgery are the cure, with radiation used in specific, hard-to-reach situations.

What it is.

Osteosarcoma is the most common cancer that starts in the bone itself. It arises from the cells that build new bone, and it tends to appear in the fast-growing bones of children, teenagers, and young adults — most often around the knee (the lower thighbone or upper shinbone) or in the upper arm — though it can occur at any age, including in older adults. The first sign is usually bone pain that may come and go, often worse at night or with activity, sometimes with swelling or a lump; occasionally the weakened bone breaks with little injury. Osteosarcoma is different from the much more common 'bone metastases,' which are other cancers (like breast or prostate) that have spread to bone — osteosarcoma begins in the bone. Treatment has advanced dramatically over recent decades: with chemotherapy and modern surgery that can usually save the limb, many patients are cured. Care is delivered by a specialized team, and radiation has a focused role for tumors in places where surgery is difficult.

How radiation treats it.

Radiation uses focused high-energy beams to damage the DNA inside tumor cells so they can no longer grow and divide. Osteosarcoma is relatively resistant to radiation, which is why surgery and chemotherapy — not radiation — are the main, curative treatments. Still, radiation has an important focused role. For tumors in places that are difficult or impossible to remove, such as the spine or pelvis, high-dose, precisely targeted radiation can help control the cancer. Because the tumor resists standard x-rays, specialized particle beams like protons are sometimes used to deliver a stronger, sharply focused dose while protecting nearby organs. Radiation can also relieve pain from a tumor or a deposit in bone. Treatments are painless and brief, given over a series of sessions. Side effects depend on the area treated and are usually temporary, such as fatigue or local skin irritation. In osteosarcoma, radiation works best as a precise, supportive tool for specific situations.

The ways we can treat it.

Definitive radiation for unresectable sites. For tumors in locations that can't be fully removed — like the spine, skull base, or pelvis — high-dose, precisely targeted radiation can help control the cancer when surgery isn't possible.

Particle (proton) therapy. Because osteosarcoma resists conventional radiation, specialized proton or other particle beams can deliver higher, more focused doses to hard-to-reach tumors while sparing nearby organs.

Palliative radiation. Focused radiation can relieve pain from a tumor or a deposit that has spread to bone, improving comfort when other treatments aren't enough.

Questions we hear often.

Is osteosarcoma the same as cancer that spreads to bone? No. Osteosarcoma begins in the bone itself, growing from bone-forming cells. 'Bone metastases' are far more common and are other cancers — like breast, prostate, or lung — that have spread to bone. They are different diseases and treated in completely different ways.

Will treatment mean amputation? Usually not. Modern limb-sparing surgery can remove the tumor and rebuild the bone or joint in most patients, preserving a functional limb. Amputation is reserved for situations where the cancer can't be safely removed otherwise. Your surgical team will discuss the best option for you.

Why isn't radiation the main treatment? Osteosarcoma is relatively resistant to radiation, so chemotherapy and surgery are the curative treatments. Radiation still has a valuable, focused role — for tumors in places that can't be removed, such as the spine or pelvis, and to relieve pain — sometimes using specialized particle beams.

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