ON THIS PAGE: You will find a list of the common tests, procedures, and scans that doctors can use to find out what’s wrong and identify the cause of the problem. To see other pages, use the menu on the side of your screen.
Doctors use many tests to diagnose cancer and find out if it has spread to another part of the body, called metastasis. 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 spread.
Your doctor may consider these factors when choosing a diagnostic test:
Age and medical condition
Type of cancer suspected
Signs and symptoms
Previous test results
In addition to a physical examination, the following tests may be used to diagnose eyelid cancer. Not all tests listed will be used for every person.
Biopsy . Because basal cell and squamous cell cancers rarely spread to other parts of the body, a biopsy is often the only test needed to determine the extent of cancer. 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 type of biopsy performed will depend on the location of the cancer.
During this procedure, performed under local (numbing) or general anesthetic, the doctor removes the suspicious tissue using techniques that test the thickness of the cancer and its margins. The margins are the healthy tissue around the lesion. The sample removed during the biopsy is analyzed by a pathologist. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. The amount of healthy tissue removed around the cancer depends on its thickness. Further treatment beyond the biopsy may not be necessary if the entire growth is removed.
If cancer is present at the edges of the tissue taken for the biopsy, additional treatment (for example, surgery, radiation therapy, or cryotherapy; see Treatment Options ) is usually necessary.
Computed tomography (CT or CAT) scan . A CT scan creates a three-dimensional picture of the inside 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. A CT scan can also 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 to swallow.
Magnetic resonance imaging (MRI) . An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. MRI can also 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 or given as a pill to swallow.
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 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. A scanner then detects this substance to produce images of the inside of the body.
Ultrasound . An ultrasound uses sound waves to create a picture of the internal organs.
To plan treatment, the doctor will determine the extent, or stage, of the cancer. The stage depends on how thick or large the tumor is and whether there is evidence that the cancer may have spread. Occasionally, a patient’s lymph nodes may be removed to determine if the cancer has metastasized. The doctor may perform other tests, including blood sample analysis, and diagnostic scans of the liver, bones, and brain. Read Stages and Grades  for more information.
After diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is cancer, these results also help the doctor describe the cancer. This is called staging.
The next section in this guide is Stages and Grades , and it explains the system doctors use to describe the extent of the disease. Or, use the menu on the side of your screen to choose another section to continue reading this guide.