What is Osteosarcoma?
Osteosarcoma is a bone cancer that usually found in the shinbone (tibia) near the knee, the thighbone (femur) near the knee, or the upper arm bone (humerus) near the shoulder. It is a very common type of bone cancer in children.
Osteosarcoma tends to develop during growth spurts in early adolescence. This may be because the risk of tumors increases during this period of rapid bone growth.
This type of cancer is more common in boys than in girls. It is also more common in tall children and African-Americans. In children, the average age of diagnosis is 15. Osterosarcoma can be seen in adults over the age of 60 and it can also be seen in people who have undergone radiation for cancer treatment. Individuals who have a family history of cancers and who have retinoblastoma, a cancer of the retina of the eye, have a higher incidence of sarcoma.
Symptoms of Osteosarcoma
Symptoms of osteosarcoma vary depending on the location of the tumor. Common signs of this type of cancer include:
- bone pain (in motion, at rest, or when lifting objects)
- bone fractures
- limitation of motion of joints
How bone pain is experienced may vary. Your child may feel a dull ache or have pain that keeps them awake at night. If your child has bone pain — or if you notice any of the above symptoms — examine their muscles. In the case of osteosarcoma, the muscles in the cancerous leg or arm may appear smaller than those in the opposite limb.
Symptoms of osteosarcoma can mimic growing pains — pain in the legs caused by normal bone growth. However, growing pains typically stop during the early teenage years. Contact a doctor if your child has any chronic bone pain or swelling past their initial growth spurts, or if the pain is causing your child serious issues.
Tests to Detect Osteosarcoma
Your child’s doctor can use a variety of tools to diagnose osteosarcoma. They will first conduct a physical examination to look for swelling and redness. The doctor will also request information about your child’s medical history. This includes previous illnesses and past medical treatments.
Your child’s doctor may do a simple blood test to check for tumor markers. These are chemical readings in the blood that indicate the presence of cancer. Other tests used to diagnose osteosarcoma include:
- CT scan: a 3-D X-ray used to examine bones and soft organs in the body
- MRI: uses sound waves and powerful magnets to create images of internal organs
- X-ray: produces images of dense tissue inside the body, including bone
- PET scan: a full body scan often used to detect cancer
- biopsy: removal of a tissue sample from the bone for testing
- bone scan: a sensitive imaging test that shows bone abnormalities that may be missed by other imaging tools (bone scans can also tell doctors whether the cancer has spread to other bones)
Classification and Staging
Osteosarcoma can be classified as either localized (only present in the bone it started in) or metastatic (present in other areas, such as the lung, or other, unconnected bones).
Osteosarcoma tumors are staged in much the same way as other tumors, using either the Musculoskeletal Tumor Society Staging System or the American Joint Commission on Cancer guidelines.
Treatment of Osteosarcoma
Chemotherapy and surgery are effective at treating osteosarcoma.
Chemotherapy is often administered before surgery. This treatment method uses drugs that help shrink and kill cancerous cells. The length of chemotherapy treatment varies and may depend on whether the cancer has spread to other parts of the body. For example, if your child’s cancer hasn’t spread, their doctor may recommend six months of chemotherapy before surgery. Once your child finishes the course of chemotherapy, surgery will be used to remove any remaining tumors.
In most cases, surgeons can save the cancerous limb. They can surgically remove the tumor and surrounding bone, and replace the missing bone with an artificial one. Chemotherapy may resume after surgery to destroy any microscopic cancer cells.
Bone cancer can recur, even after chemotherapy and surgery. Your child will need follow-up CT scans, bone scans, and X-rays to check for new tumors.
Complications of Osteosarcoma
Chemotherapy and surgery may not completely cure osteosarcoma, and cancerous cells may continue to grow and spread. Your child’s doctor may suggest amputation to stop the spread of cancerous cells. This is the surgical removal of the cancerous limb.
This type of cancer can also spread to the lungs. Signs that bone cancer has metastasized (spread) to the lungs include:
- chest pain
- shortness of breath
- coughing up blood
- chronic cough
Chemotherapy given to your child before and after surgery may produce unpleasant side effects. These side effects include:
- hair loss
- fluid retention
- anemia (low red blood cell count)
Outlook for Osteosarcoma
The prognosis for osteosarcoma is good if your child’s tumor is confined to the original bone. In fact, 3 out of 4 people can be cured if their tumors haven’t spread elsewhere. The survival rate is about 30 percent if the cancer has spread to other parts of the body.