A physician will review a complete medical history and conduct a physical examination as the initial steps in the diagnosis of cancer. In many cases, this exam will be combined with imaging tests or blood tests if the physician suspects the spread of cancer. However, confirmation of cancer can usually be confirmed only with a biopsy of the suspected tissue. This helps determine whether an abnormality is the result of cancer, or another illness such as infection.

Once a patient’s primary cancer has been diagnosed, the physician will try to determine how far it has spread. This is known as staging. The tumor’s exact type and size will help the physician to determine the risk of metastasis.

Tests used to diagnosed metastatic cancer include:

• X-rays. Creates an image of part of the body by using low doses of radiation. Chest x-rays and bone x-rays can help spot masses and evidence of their growth. However, they are not effective in determining the type of cancer present or where it began.
  
  
• Computed axial tomography (CAT) scan. Uses multiple x-ray images, taken from different angles, to create three-dimensional images of body structures. CAT scans can identify signs of metastatic cancer such as enlarged lymph nodes or masses in internal organs.
  

• Magnetic resonance imaging (MRI). Produces clear cross-sectional or three-dimensional images of the body’s tissues, even through bone and other obstructions. This produces images similar to those of a CAT scan and, for some areas, with better detail. MRI may be completed with dye (contrast medium) that can help highlight tissues and organs.
  
  
• Ultrasound. Sends and receives high-frequency sound waves to create images of internal organs or tissues. It can reveal masses in some organs, such as the breast or uterus in women.
  
  
• Radionuclide bone scan. Test in which tiny amounts of radioactive materials (tracers) are introduced into the patient’s body. The tracers emit a type of energy called gamma rays, which are detected by special devices and converted to images. This scan can help reveal whether a cancer has metastasized to bones.
  
  
• Positron emission tomography (PET) scan. A glucose substance is combined with small amounts of radioactive material and injected into a patient’s vein. Cancer cells in the body absorb the substance and they appear as hot spots on th image. PET scan is frequently used to determine the location and extent of cancer metastasis in the body.
  
  
• Tumor markers. Some types of cancer release substances into the bloodstream that can be detected through blood tests. These substances, known as tumor markers, sometimes suggest the presence of metastatic cancers, especially when levels of the substance are very high.
  
  
• Other blood chemical tests. Metastasis to certain organs can damage their cells or alter their metabolism. When this occurs, it may cause certain substances to be released into the bloodstream that can then be detected during blood testing.
  
  
• Biopsy. Procedure to obtain a sample of suspected tissue or bone that is sent to a laboratory for analysis. The analysis is done by a specialized physician known as a pathologist. Biopsy is the definitive way to diagnose cancer and is necessary to determine the presence of the disease.
  
  
• Laparotomy. Surgical technique that involves small incisions in the abdomen to allow a suspicious area to be viewed and biopsied if necessary.
  
  
• Examination of body fluids. Cancer cells discovered in the cerebrospinal fluid indicate that cancer has spread to the brain or spinal cord. Cancer cells can sometimes be found in the space around the lungs (pleural fluid) or in the abdomen (peritoneal fluid). The presence of such cells indicates metastasis in those organs or in their lining membranes.

If cancer appears in more than one area of the body, physicians will try to diagnose whether the second cancer is directly related to the first, or if it developed separately. This is important, because treatment options and the patient’s ultimate prognosis varies depending on whether a cancer is primary or metastatic.