What is osteosarcoma?

Osteosarcoma is a kind of bone cancer. It most often starts in a leg bone (either the femur or the tibia) in the area of the knee or in the upper arm bone (the humerus) near the shoulder. Osteosarcoma can spread (metastasize) to other parts of the body, most often to the lungs or other bones.

Who gets osteosarcoma?

Overall, osteosarcoma is not a common cancer. Only about 400 cases happen in the United States each year. Osteosarcoma is, however, the most common bone cancer in children and teenagers. It most often starts between 10 and 20 years of age. Osteosarcoma has no known cause.

What are some signs of osteosarcoma?

Your child may have a dull aching pain in the bone or joint where the osteosarcoma is. The pain can awaken your child from sleep. Often, there is a firm swelling or lump in the area of the tumor.

If the cancer is in a leg bone, your child may limp. Also, the muscles in the arm or leg that has the osteosarcoma may look smaller than those in the opposite arm or leg. Sometimes, the bone can break in the area of the tumor, because the tumor weakens the bone.

What tests will the doctor use to tell if my child has osteosarcoma?

X-ray

If your child has signs of an osteosarcoma, your doctor will order x-rays. If there is a tumor, it will usually show up on the x-ray.

MRI and CT

Your child will also have an MRI scan, a CT scan (also called a CAT scan), or both. MRI and CT scans help the doctor see how much bone the tumor has destroyed, and if the tumor has grown outside the bone into nearby muscles.

Biopsy

A biopsy is important because other kinds of tumors (some that are not cancer) and infections can sometimes look like an osteosarcoma on an x-ray. For the biopsy, a doctor with special training in the treatment of bone cancer takes a piece of the tumor from the bone. This piece is looked at under a microscope to make sure the tumor is an osteosarcoma.

Other Tests

If your child has osteosarcoma, another CT scan will be done to see if the cancer has spread to the lungs. Your child will also have a bone scan to see if the cancer has spread to other bones. Before the bone scan, your child will be given a shot of a harmless radioactive substance that goes into the cancer cells so they show up on the scan. Other tests may also be needed.

How is osteosarcoma treated?

Osteosarcoma is treated with chemotherapy and surgery. For chemotherapy, your child will be given medicines that kill the main tumor and any tumor cells that have traveled to other parts of the body. Your child will have chemotherapy for about 9 to 12 months. This treatment is started before surgery to kill the tumor or make it smaller. This makes surgery easier.

At one time, all people with osteosarcoma had an amputation (removal of part or all of the arm or leg that had the tumor). Now, almost everyone with this cancer can have “limb-sparing” surgery. In this surgery, the tumor is removed along with the area of bone that it grew in. Sometimes an entire joint, like the knee joint, is removed. Then the missing bone is replaced with an artificial metal bone called an endoprosthesis (say: end-o-pross-thee-sis).

After the surgery, your child will have more chemotherapy.

What can we expect after treatment?

Today, about three out of four people with osteosarcoma can be cured if the cancer has not spread to other parts of the body. Almost everyone who is treated with limb-sparing surgery ends up with an arm or leg that is painless and works well.

To make the leg or arm strong, and so that it works well again, your child will have to do special exercises for several months after the surgery. If amputation is necessary, your child will have intense rehabilitation for several weeks.

After the chemotherapy is over, your child will need to see the bone cancer specialist regularly for several years. Your child will have frequent CT scans of the lungs, bone scans and x-rays of the arm or leg to see if the tumor comes back in the bone, or travels to the lungs or other parts of the body. X-rays will be checked to make sure that your child has no problems with the metal bone.