Osteosarcoma
What is it?
Osteosarcoma is the most common type of childhood bone cancer. A sarcoma is a bone tumor that contains cancer cells.
"Osteo" is from the Greek word for bone.
Who gets it?
Osteosarcomas account for approximately 5% of all childhood cancers. They are most common in children and young adults between the ages of 10 and 20, affecting boys twice as often as girls. This type of cancer is most often seen in adolescents who are experiencing a growth spurt. Because it develops from cells that manufacture growing bone, research has shown that teenagers who are above average in height are at a greater risk for developing osteosarcoma. Children with inherited retinoblastoma, which is cancer of the retina of the eye, or Li-Fraumeni syndrome, which is a gene mutation that results in an unusually high risk of childhood cancer, also are at a higher risk for osteosarcoma. Children who have received radiation therapy for other types of cancers may have an increased risk of developing osteosarcoma in any bones that have been exposed to high levels of radiation. While osteosarcoma is most common in children and young adults, it can occur at any
age.
What causes it?
Osteosarcoma develops from osteoblasts, which are the cells that manufacture growing bone. Most cases of osteosarcoma occur during times of intense bone growth when errors occur in the DNA of growing bone cells. DNA stands for deoxyribonucleic acid. DNA carries our genetic
"code" on thread-like structures called chromosomes. In some cases, these DNA errors, or mutations, occur for no apparent reason. In other cases, the tendency to develop an osteosarcoma is inherited from one or both parents. Children with retinoblastoma or Li-Fraumeni syndrome have inherited DNA mutations that make them more likely to develop osteosarcoma and other tumors. Radiation exposure can also trigger DNA mutations. However, the amount of radiation contained in routine diagnostic x-rays does not increase a person's risk of developing any type of bone
cancer.
What are the symptoms?
More than half of all osteosarcomas occur around the knee. They commonly affect the fastest-growing bones of the body, which are the long bones supporting the arms and legs. These tumors grow very quickly, and cause pain and swelling in the area around the tumor. In some cases, there may be a visible lump in the affected area. Other symptoms of osteosarcoma can include fever, fatigue, and weight loss. With time, the osteosarcoma weakens the bone structure and the bone breaks for no apparent reason. In fact, osteosarcoma is often diagnosed when treating a broken
bone.
How is it diagnosed?
To diagnose an osteosarcoma, your doctor will perform a thorough physical examination. He or she will order x-rays of the painful area. If the x-rays show a tumor, your doctor may also order a computed tomography (CT) scan to pinpoint the exact location of the tumor and to determine if it has spread to the muscles and fat around the bone. This will help target the location for a bone biopsy, which will help confirm a diagnosis. There a two ways to perform this biopsy. A needle biopsy is performed under local anesthesia, which means the affected area is numbed so your child will not feel pain during the procedure. Then, a long, thin needle is inserted into the tumor and a sample of tumor cells and tissues is removed for examination under a microscope. An open biopsy is performed under general anesthesia, which means your child will be given drugs to put him or her into a sleep-like state. With an open biopsy, a piece of the tumor is removed surgically. Magnetic resonance imaging (MRI) is another diagnostic technique that may be used to determine the location and number of tumors. Your doctor will also order bone scans and CT scans of other parts of your child's body, such as the chest, to determine whether the cancer has spread. A blood sample will be taken for a complete blood count (CBC), which may help determine whether the cancer has spread to the bone marrow. Determining whether and how far the cancer has spread from its original location is called
"staging," and helps determine treatment. The stages of osteosarcoma are classified as localized (low grade) or metastatic (high grade). Localized means the cancer has not spread beyond the bone where it originated. Metastatic means the cancer cells have spread to other areas of the body. Osteosarcoma most commonly spreads to the lungs. However, it can also travel to other bones, tissues, and organs. Osteosarcoma may be classified as intermediate when it involves more than one
bone.
What is the treatment?
Osteosarcomas are treated by cancer specialists called oncologists, and bone specialists, called orthopedic surgeons. While treatment depends upon the cancer's stage, most cases are treated with a combination of surgery and chemotherapy. Chemotherapy involves doses of very strong medicine that are often given first to control the growth of the tumor by killing the cancer cells. Then, the tumor is surgically removed and any gap in the bone is filled in with a bone graft from another part of the body or a metal rod. In the past, the affected arm or leg was surgically removed, called amputation. Today, however, more than 70% of all osteosarcomas are treated with limb-saving surgery. Amputation is performed only when the tumor has spread beyond the bone to the surrounding nerves and blood vessels. If the cancer has spread to other areas of the body, your child will need surgery to remove those tumors as well.
Your child will receive additional chemotherapy treatment after the surgery. Chemotherapy can make your child feel sick and weak, and lose his or her hair. These side effects are temporary and will go away once the chemotherapy treatments are finished. Your doctor can prescribe medicine to counteract these side effects if your child cannot tolerate them. If your child has had surgery to save his or her limb, it will take some time and physical therapy to regain use of the affected limb. If he or she has had a limb amputated, a prosthetic (artificial) limb can be fitted. It may take anywhere from three to six months for your child to learn to use the prosthetic leg or arm. In addition to physical therapy, most adolescents will also need psychological therapy to help them cope with their condition during an already difficult time of life. After treatment is complete, your child will continue to have follow-up diagnostic tests such as CAT scans, bone scans, and x-rays to ensure the tumor is gone. Survival rate depends upon the stage of the cancer and the success of
treatment.
Self-care tips
Because many cases of osteosarcoma occur for no apparent reason, or are genetically inherited, there are no known steps to take to prevent this type of cancer. Because osteosarcoma usually develops during adolescence, it's important to have your child examined by a doctor if he or she develops any unexplained bone pain, tenderness, or swelling.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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