It is important that there is little delay in the diagnosis of osteosarcoma. The earlier the diagnosis, the greater is the chance for cure.

Signs and Symptoms of Osteosarcoma

Pain in the affected bone is the most common complaint of patients with osteosarcoma. At first, the pain is not constant and may be worse at night. The pain increases with activity and may result in a limp if a leg is involved. Swelling in the area of the pain site may not occur until weeks later.

Depending on the location of the tumor, it may be possible to feel a lump or mass. Although osteosarcoma may weaken the bone it develops in, the bones do not often break. Telangiectatic osteosarcomas, which are rare, tend to weaken bones more than other forms of osteosarcoma. About 30% of telangiectatic osteosarcomas cause a fracture at the tumor site. Patients with a fracture next to or through an osteosarcoma will describe a limb that was sore for a few months and suddenly became severely painful when the fracture occurred.

Unfortunately, limb pain and/or swelling are seen very commonly seen in normal, active teenagers, so they are often not thoroughly evaluated. This can delay a diagnosis. These symptoms are less common in adults and should be a sign to see a doctor.

Imaging Studies

Bone x-ray: Doctors will usually recognize (or at least suspect) osteosarcoma on regular x-rays of the bone. However, a biopsy (sample of the tumor for examination under the microscope) is needed to prove that cancer is really present.

Computed tomography (CT): The CT scan is an x-ray procedure that produces detailed cross-sectional images of the body. Instead of taking one picture, like a conventional x-ray, a CT scanner takes many pictures as it rotates around you. A computer combines these pictures into an image of a slice of your body. The machine will create multiple images of the part of your body that is being studied.

Often after the first set of pictures is taken, you or your child will receive an intravenous (IV) injection of a "dye" or contrast agent that helps better outline structures in the body. A second set of pictures is then taken.

You or your child will need an IV line through which the contrast dye is injected. Some people are allergic to the dye and get hives or a flushed feeling or, rarely, have more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you or your child has ever had a reaction to any contrast material used for x-rays.

A CT scan of the affected bone can show if the tumor has grown into nearby muscle, fat, etc. The scan will also help the surgeon pick the best area to biopsy. A chest CT scan is very important in determining if osteosarcoma has metastasized (spread) to the lungs.

Magnetic resonance imaging (MRI): MRI scans use radio waves and strong magnets instead of x-rays. Energy from the radio waves is absorbed by tissues of the body. The energy is then released in a pattern affected by the type of tissue and by certain diseases. A computer is used to translate the pattern of radio waves given off by tissues into a very detailed cross-sectional image of parts of the body. Not only does this produce cross sectional slices of the body like a CT scanner, it can also produce slices that are parallel with the length of your body. A contrast material might be injected just as with CT scans.

MRI gives more details of the soft tissues, the bone tumor, and the bone marrow cavity than a CT scan. It is thought to be better for evaluating osteosarcoma. Sometimes, the MRI can help find small tumors several inches away from the main tumor (called "skip metastases"). Finding these small tumors is important for planning the type of surgery that is best for each patient. MRI scans are also very helpful in looking at the brain and spinal cord.

MRI scans are a little more uncomfortable than CT scans. First, they take longer – often up to an hour. Also, you have to be placed inside tube-like equipment, which is confining and can upset people with claustrophobia (fear of enclosed places).

Chest x-ray: This test can spot cancers if they are large enough (one-half inchor larger) that have spread from the original site in the bone. (A CT scan of the chest is more sensitive; it can spot very small tumors.)

Radionuclide bone scan: During a bone scan, a radioactive tracer is injected into a vein. The most commonly used tracer is Technetium 99. Another tracer that can also be used is Thallium 201; this tracer seems to provide better information regarding the response of the tumor to chemotherapy, but it also exposes children to much higher radiation, so it is seldom used in younger people. The tumor absorbs these radioactive materials, which are detected by a special type of camera. A computer reconstructs images showing all the bones of the body. Osteosarcoma will usually appear as a darker spot in the scan indicating more concentrated radioactivity. The bone scan can also detect spread of the osteosarcoma to the lungs and/or to other bones.

Positron emission tomography (PET): This is a new type of radioactive scan. With PET, you or your child will receive an infusion of glucose (a form of sugar) that contains a radioactive atom. A special camera can detect the radioactivity. Cancer cells in the body absorb high amounts of the radioactive sugar, because of their high rate of metabolism. PET may be useful for looking at spread of cancer.

Blood Tests

High levels of certain chemicals in the blood can suggest that the osteosarcoma is more advanced than it appears. The most important of these are called alkaline phosphatase and LDH. They are released into the blood by osteosarcoma cells. Higher levels indicate a worse outlook for cure.

Biopsy

A biopsy procedure takes a sample of tumor tissue to examine under the microscope and use for certain other laboratory tests. Probably in no other cancer is it as important to perform this procedure properly. If the biopsy is not done properly, the affected limb may have to be amputated (removed by cutting).

A biopsy may be done under local or general anesthesia. With local anesthesia, the anesthetic is injected with a small needle to numb the tissue over the sample site. During general anesthesia, drugs are injected into a vein or are breathed in so the patient is asleep during the operation.

There are 2 different types of biopsies: the needle biopsy and the open biopsy.

The needle biopsies can use thin (also called fine) or thick needles. The fine needle biopsy removes very small fragments of tissue. With the thick needle biopsy, the surgeon obtains a cylindrical core of tissue. Most experts recommend this thicker core biopsy.

In the open biopsy, the surgeon cuts through the skin, exposes the tumor, and then cuts out a piece of tissue. This biopsy must be done by an expert in bone tumors, or it’s possible the chance for saving a limb may be lost. If possible, the opening through the skin used in the biopsy procedure should be lengthwise along the arm or leg because this is the orientation of the incision that will be used for the operation to remove the cancer. The entire scar of the original biopsy will also have to be removed so planning the biopsy incisions in this way minimizes the amount of tissue that needs to be removed later on.

Tissue removed by biopsy is always examined under the microscope. Examining a bone tumor may also involve tests of the chromosomes or genes. These tests may help distinguish osteosarcoma from other cancers that look similar under the microscope, and can sometimes help predict whether the osteosarcoma is likely to respond to therapy.

Revised: 03/19/2007