n WHAT IS METASTASIS? Metastasis refers to the spread of a tumor from its original location (primary site) to other parts of the body. When osteosarcoma spreads, it usually goes to the lungs. It also can spread to other bones. About 20% of children with osteosarcoma have metastasis at the time they are diagnosed. It is important to determine whether any metastatic disease is present at diagnosis to decide on the best treatment for your child.
n WHAT TESTS AND PROCEDURES WILL MY CHILD NEED? To diagnose osteosarcoma and determine the extent of your child’s disease, a number of tests and procedures are necessary, including many of the following:
Tumor Biopsy This test is necessary to determine what type of cancer the child has. It also helps determine what treatment should be chosen. The biopsy is usually done in the operating room by a surgeon while the child is under heavy sedation or anesthesia. Some medical centers do the biopsy in the radiology department. In some cases, the biopsy sample is obtained through a needle that is guided into the tumor. In other cases, an incision is made. Your child’s comfort and anxiety level will always be considered in planning procedures that involve needles.
MRI Magnetic resonance imaging (MRI) is a test that gives very exact pictures of the muscles, nerves, blood vessels, and tumor inside the body. The child is asked to lie on a table, which is then moved into a tube-like machine that surrounds the child with a magnetic field. The test is painless, but the machine makes quite a bit of noise. The child must not move at all during the test. If your child is not able to lie completely still, a sedative may be given to make him or her sleep through the MRI. Sometimes a small amount of dye is injected into a vein. Generally, no side effects from either type of dye occur, although allergic reactions are possible. CT Scan The computerized tomography (CT) scan is a computer-assisted X ray that shows very precise pictures. This is used to examine the lungs for tumors. The procedure is painless, but the child must be able to lie absolutely still during the scan. Some children require sedation to help them lie still. Sometimes a small amount of dye is injected into a vein. Generally, no side effects from either type of dye occur, although allergic reactions are possible. Bone Scan A bone scan is done to look at all bones in the body for areas of bone where the tumor is growing. It involves injecting a small amount of isotope (radioactive marker) into a vein, allowing 2–3 hours for the isotope to distribute itself throughout the body, and then having the child lie still for the scan (pictures) to be taken of the entire body. This isotope is picked up by tumor cells so that the tumor’s location in the body can be seen. The scanning process is painless, but some children need sedation to help them lie still.
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