Doctors use many tests to diagnose cancer and find out if it has metastasized (spread). 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. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
• Type of cancer suspected
• Severity of symptoms
• Previous test result

The following tests may be used to diagnose oral and oropharyngeal cancer:

Physical examination. Dentists and doctors often find lip and oral cavity cancers during routine check-ups. If a person shows signs of oral or oropharyngeal cancer, the doctor will take a complete medical history, asking about the patient’s symptoms and risk factors. The doctor will feel for any lumps on the neck, lips, gums, and cheeks. Since patients with oral and oropharyngeal cancer have a higher risk of other cancers elsewhere in the head and neck region, the area behind the nose, the larynx (voice box), and the lymph nodes of the neck are also examined.

Endoscopy. This test allows the doctor to see inside the mouth and throat. Typically, an endoscope (a thin, flexible tube with an attached light and view lens) is inserted through the nose to examine the head and neck areas. Sometimes, a rigid endoscope (a hollow tube with a light and view lens) is placed into the back of the mouth to see the back of the throat in more detail. The examination has different names depending on the area of the body that is examined, such as laryngoscopy (larynx), pharyngoscopy (pharynx), or a nasopharyngoscopy (nasopharynx). To make the patient more comfortable, these examinations are performed using an anesthetic spray to numb the area. If tissue looks suspicious, the doctor will take a biopsy. Tests are often done in the doctor’s office; however, sometimes, an endoscopy must be performed in an operating room at a hospital using a general anesthesia.

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 performed will depend on the location of the cancer. In a fine needle aspiration biopsy, cells are withdrawn using a thin needle inserted directly into the tumor. The cells are examined under a microscope for cancer cells (called cytologic examination).

Oral brush biopsy. During routine dental examinations, some dentists are using a newer, simple technique to detect oral cancer in which a dentist uses a small brush to gather cell samples of a suspicious area. The specimen is then sent to a laboratory for analysis. This oral brush biopsy procedure is easy and can be done right in the dentist’s chair with very little or no pain. If cancer is found using this method, it is recommended that a traditional biopsy (see above) be done to confirm results.

X-ray. An x-ray is a way to create a picture of the structures inside of the body, using a small amount of radiation. A dentist may take extensive x-rays of the mouth, including a panorex (panoramic view; see below).

Barium swallow. Two types of these tests are generally used to look at the oropharynx and swallowing. The first is a traditional barium swallow; during an x-ray exam, the patient is asked to swallow liquid barium so the doctor can look for any changes in the structure of the oral cavity and throat and see whether the liquid passes easily to the stomach. A modified barium swallow, or videofluoroscopy, is used to assess swallowing; the patient is asked to swallow liquid barium, pudding, and a cracker coated with barium.

Panorex. This is a rotating, or panoramic, x-ray of the upper and lower jawbones to detect bone destruction from cancer, or to evaluate teeth before radiation therapy or chemotherapy.

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.  Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail. A CT scan can help a doctor decide whether the cancer can be surgically removed and determine whether the cancer has spread to lymph nodes in the neck or lower jawbone.

Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body, especially images of soft tissue, such as the tonsils and base of the tongue. A contrast medium may be injected into a patient’s vein to create a clearer picture.

Ultrasound. An ultrasound uses sound waves to create a picture of the internal organs. This test can detect the spread of cancer to the lymph nodes in the neck (called the cervical lymph nodes).

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 substance is injected into a patient’s body. This substance is absorbed mainly by organs and tissues 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.

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

After these 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. Learn more about the first steps to take after a diagnosis of cancer.