Bone Cancer in Children: Osteosarcoma and Ewing Sarcoma

Bone cancer in children is rare. The two most common types are osteosarcoma and Ewing sarcoma. Both usually start in a long bone, often near a joint like the knee. Both are treated with chemotherapy and surgery together. Most children are treated as part of a clinical trial. Outcomes have improved a great deal over the past several decades.

Osteosarcoma mostly affects teens and young adults. About 440 people under age 20 are diagnosed with it each year in the United States. It often shows up during a growth spurt. More than half the time, it starts in a long bone near the knee. Ewing sarcoma also mostly affects teens and young adults, from the teen years into the mid-20s. It can start in a bone. It can also start in the soft tissue around a bone.

The most common signs are pain and swelling in a bone or joint. These signs may come and go at first. A limp, stiffness, or a fracture with no clear injury can also be a sign. Some children with Ewing sarcoma also get fever, fatigue, or weight loss they cannot explain. Any bone pain that keeps coming back is worth a doctor visit, especially in a growing child.

Doctors start with imaging tests. An X-ray comes first. A CT scan or MRI usually follows, to see the tumor in more detail. A biopsy is the step that confirms cancer. A small piece of the tumor is removed and checked under a microscope. This step matters a lot. Ideally, the surgeon who does the biopsy should be the same surgeon who does the final tumor surgery later. A poorly placed biopsy can make that later surgery harder.

Treatment usually starts with chemotherapy. Doctors give it before surgery, to shrink the tumor and kill cancer cells that imaging cannot see. Surgery follows, to remove the tumor completely. Many children can have limb-sparing surgery. This removes the cancer while keeping the arm or leg. Some children need amputation instead. That choice depends on the tumor's size and exact location. Research has found that survival is about the same either way. After surgery, children usually get more chemotherapy, to kill any cancer cells left behind.

Ewing sarcoma is also treated with chemotherapy first. This usually lasts several months, to shrink the tumor. Then comes local treatment: surgery, radiation, or sometimes both. The choice depends on where the tumor is, and how it responded to chemotherapy. More chemotherapy usually follows. The whole process can take six months to a year. If Ewing sarcoma comes back after treatment, doctors may use high-dose chemotherapy with a stem cell transplant.

Most children with osteosarcoma or Ewing sarcoma in the United States are treated through the Children's Oncology Group. Joining a trial usually means your child gets the current best standard treatment. It is closely tracked. Sometimes it includes a promising new addition. Ask your child's team whether a trial is open for their specific cancer.

Recovery does not stop when treatment ends. Children who had limb-sparing surgery often need physical therapy to rebuild strength and movement. Growing bones can need extra surgery later, to keep both legs or arms an even length. Ask your child's team for a written survivorship plan that covers physical therapy, growth monitoring, and long-term checkups.

Treat a fever during chemotherapy as an emergency, not a message to leave. Phone the oncology team at once, day or night, if your child's temperature reaches 100.4°F (38°C) or higher or if they get shaking chills. Chemotherapy lowers blood counts, and CDC says an infection during chemotherapy can become life-threatening quickly. If you cannot reach the team in minutes, take your child to an emergency department and tell the staff straight away that they are on chemotherapy. Call 911 if breathing becomes hard.

Call the care team the same day for sudden severe pain in the affected limb, or a bone that gives way or breaks after only a small knock.

Ask whether limb-sparing surgery is possible, and what recovery and rehab will look like. Ask how many rounds of chemotherapy are planned, and what side effects to expect. Ask whether a clinical trial is available. Ask what follow-up scans and appointments will look like once treatment ends. Bone cancers can come back, and regular monitoring catches this early.

• National Cancer Institute — Osteosarcoma and Undifferentiated Pleomorphic Sarcoma of Bone Treatment (PDQ).
• National Cancer Institute — Ewing Sarcoma Treatment (PDQ).
• National Cancer Institute — Infections in People with Cancer.
• CDC — Fever and Cancer Treatment.