Bone Cancer (Sarcoma of Bone): Diagnosis

Approved by the Cancer.Net Editorial Board, 09/2022

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of a medical problem. Use the menu to see other pages.

Doctors use many tests to find, or diagnose, cancer. They also do tests to learn if cancer has spread to another part of the body from where it started. If the cancer has spread, it is called metastasis. For example, imaging tests, such as an x-ray, may be used to diagnose bone sarcoma and to find out whether the cancer has spread. Imaging tests show pictures of the inside of the body. Benign and cancerous tumors usually look different on imaging tests, which are described below.

Although imaging tests may suggest a diagnosis of bone sarcoma, a biopsy will often be performed to confirm the diagnosis and to find out the subtype. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.

Bone sarcomas are rare, and the way a biopsy is performed can affect the outcomes of surgery and risk of recurrence. Whenever a bone sarcoma is suspected, it is extremely important to see a surgeon who specializes in sarcomas, such as an orthopedic oncologist, before any surgery or a biopsy is performed.

How bone sarcoma is diagnosed

There are different tests used for diagnosing bone sarcoma. Not all tests described here will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

In addition to a physical examination, the following tests may be used to diagnose or determine the stage (or extent) of a bone sarcoma:

  • Biopsy. A biopsy is the only way to make a definite diagnosis, even if other tests can suggest that cancer is present. During biopsy, a small amount of tissue is removed for examination under a microscope. A pathologist analyzes the sample(s). A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. Whether a needle biopsy or incisional biopsy is performed depends on where the cancer is located. During a needle biopsy, a small hole is made in the bone, and a tissue sample is removed from the tumor with a needle-like instrument. During an incisional biopsy, the tissue sample is removed after a small cut is made in the tumor. Sometimes it may not be possible to do a biopsy.

    The type of biopsy and how it is done are important in diagnosing and treating sarcoma, so patients should be seen in a sarcoma specialty center even before the biopsy is performed. At the sarcoma center, the treating surgeon can identify the location for the biopsy. It is also important to have an expert pathologist review the sample of tissue removed to appropriately diagnose a sarcoma.

  • X-ray. An x-ray creates a picture of the structures inside of the body using a small amount of radiation.

  • Bone scan. A bone scan may be used to help determine the stage of a bone sarcoma. A bone scan looks at the inside of the bones using a radioactive tracer. The amount of radiation in the tracer is too low to be harmful. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears lighter to the camera, and areas of injury, such as those caused by cancerous cells or sometimes a broken bone, stand out on the image.

  • Computed tomography (CT or CAT) scan. A CT scan takes pictures of the inside of the body using x-rays taken from different angles. A computer combines these pictures into a detailed, 3-dimensional image that shows any abnormalities or tumors. A CT scan can be used to measure the tumor’s size. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a pill or liquid to swallow.

  • Magnetic resonance imaging (MRI). An MRI produces detailed images of the inside of the body using magnetic fields, not x-rays. MRI can be used to measure the tumor’s size. A special dye called a contrast medium is given before the scan to create a clearer picture. This dye can be injected into a patient’s vein. MRI scans are used to check for any tumors in nearby soft tissue. MRIs provide a road map for the orthopedic oncology surgeon to perform the best cancer surgery possible.

  • Positron emission tomography (PET) or PET-CT scan. A PET scan may be used to help determine the stage of a bone sarcoma. A PET scan is a way to create picture of organs and tissues inside the body. A PET scan is usually combined with a CT scan (see above), called a PET-CT scan. However, you may hear your doctor refer to this procedure just as a PET scan. A small amount of a radioactive sugar substance is injected into the patient’s body. This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. However, the amount of radiation in the substance is too low to be harmful. A scanner then detects this substance to produce images of the inside of the body.

  • Blood tests. Sarcomas are never diagnosed by a laboratory blood test. People with osteosarcoma or Ewing sarcoma can occasionally have higher alkaline phosphatase and lactate dehydrogenase levels in the blood, but high levels of these substances may also have any of a number of benign causes, such as growing in children or a healing broken bone.

After diagnostic tests are done, your doctor will review the results with you. If the diagnosis is cancer, these results also help the doctor describe the cancer. This is called staging and grading.

The next section in this guide is Stages and Grades. It explains the system doctors use to describe the extent of the disease. Use the menu to choose a different section to read in this guide.