Diagnosis

Doctors use many tests to diagnose cancer and determine if it has metastasized. Some tests may also determine which treatments may be the most effective. 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.

Imaging tests may be used to find out whether the cancer has metastasized. Benign and cancerous tumors usually look different on imaging tests. A benign tumor has round, smooth, well-defined borders. A cancerous tumor has irregular, poorly defined border due to aggressive growth. There may also be evidence of bone destruction on an image of a cancerous tumor. Imaging tests may suggest a diagnosis of bone cancer, but a biopsy will always be performed to confirm the diagnosis and determine the subtype. It is extremely important for a patient to be seen by a sarcoma specialist before any surgery or a biopsy is performed.

Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
  
  
• The type of cancer suspected
  
  
• Severity of symptoms
  
  
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose bone cancer:

Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). The type of biopsy (needle or incisional, see below) performed will depend on the location of the cancer. However, there are some cases where a biopsy may not be able to be performed.

For 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. In an incisional biopsy, the tissue sample is removed after a small cut is made in the tumor.

Blood tests. Some laboratory tests may help detect bone cancer. Alkaline phosphatase and lactate dehydrogenase levels may be higher in patients with osteosarcoma or Ewing’s sarcoma. However, it is important to note that alkaline phosphatase is normally high when cells that form bone tissue are very active (for example, when children are growing or a broken bone is mending), so high levels do not always mean cancer. Patients with chondrosarcoma may have abnormal glucose tolerance tests.

X-ray. An x-ray is a picture of the inside of the body. Typically, if an x-ray suggests cancer, the doctor would order other imaging tests.

Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a vein to provide better detail.

Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture. MRI scans are useful to check for tumors in nearby soft tissues.

Bone scan. A bone scan uses a radioactive tracer to look at the inside of the bones. 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 gray to the camera, and areas of injury, such as those caused by cancerous cells, appear dark.

Positron emission tomography (PET) scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images.

Integrated PET-CT scan. This scanning method collects images from both CT and PET scans at the same time, and then combines the images. This technique has the advantage of looking at both the structure and metabolism of the tumor and normal tissue. This information can be helpful to plan treatment and determine the benefits of different treatments.

Learn more about what to expect when having common tests, procedures, and scans.

Find out more about common terms used during a diagnosis of cancer.