Osteosarcoma

(Cáncer infantil: Osteosarcoma)

Osteosarcoma is the most common type of bone cancer, and the sixth most common type of cancer in children. Although other types of cancer can eventually spread to parts of the skeleton, osteosarcoma is one of the few that actually begin in bones and sometimes spread (or metastasize) elsewhere, usually to the lungs or other bones.

Because osteosarcoma usually develops from osteoblasts (the cells that make growing bone), it most commonly affects teens who are experiencing a growth spurt. Boys are more likely to have osteosarcoma than girls, and most cases of osteosarcoma involve the knee.

Most osteosarcomas arise from random and unpredictable errors in the DNA of growing bone cells during times of intense bone growth. There currently isn't an effective way to prevent this type of cancer. But with the proper diagnosis and treatment, most kids with osteosarcoma do recover.

Risk for Childhood Osteosarcoma

Osteosarcoma is most often seen in teenage boys, and evidence shows that teens who are taller than average have an added risk for developing the disease.

Kids who have inherited one of the rare cancer syndromes also are at higher risk for osteosarcoma. These syndromes include retinoblastoma (a malignant tumor that develops in the retina, usually in children younger than age 2) and Li-Fraumeni syndrome (a kind of inherited genetic mutation). Because exposure to radiation is another trigger for DNA mutations, children who have received radiation treatments for a prior episode of cancer are also at increased risk for osteosarcoma.

Symptoms of Osteosarcoma

The most common symptoms of osteosarcoma are pain and swelling in a child's leg or arm. It occurs most often in the longer bones of the body — such as above or below the knee or in the upper arm near the shoulder. Pain may be worse during exercise or at night, and a lump or swelling may develop in the affected area up to several weeks after the pain starts. Pain that persistently wakes the child up at night or pain at rest are of particular concern. In osteosarcoma of the leg, the child may also develop an unexplained limp. In some cases, the first sign of the disease is a broken arm or leg, because the cancer has weakened the bone to make it vulnerable to a break.

If your child or teen has any of the above symptoms, it's important to see a doctor.

Diagnosing Osteosarcoma

To diagnose osteosarcoma, the doctor will likely perform a physical exam, obtain a detailed medical history, and order X-rays to detect any changes in bone structure. The doctor may also order a magnetic resolution imaging (MRI) scan of the affected area, which will find the best area to biopsy and show whether the osteosarcoma has spread from the bone into nearby muscles and fat. The doctor will also order a bone biopsy to obtain a sample of the tumor for examination in the lab. This is best done by an orthopedic surgeon experienced in the treatment of osteosarcoma (orthopedic oncologist).