Oral cancer diagnosis and detection

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on May 31, 2022.

Many oral cancers are found by a dentist during a routine dental exam. But because the disease doesn’t usually cause symptoms in its early stages, paying attention to changes in the oral cavity is critical, especially for people who regularly smoke tobacco and drink alcohol. Along with a clinical exam of the mouth, other tests or procedures designed for diagnosing oral cancer include those listed below.

Barium swallow

A barium swallow test may show irregularities in the larynx, pharynx, mouth and surrounding areas, and may often detect small, early oral tumors.


Only a biopsy can confirm an oral cancer diagnosis. A sample of tissues or cells is required for a biopsy, which must be conducted before treatment begins. Two types of biopsies are typically used for diagnosing oral cancers.

Incisional biopsy: A small piece of tissue is cut from an abnormal-looking area. If the abnormal region is easily accessed, the sample may be taken at a doctor’s office. If the tumor is deeper inside the mouth or throat, the biopsy may need to be performed in an operating room, with general anesthesia administered to prevent pain.

Exfoliative cytology: A suspicious area is gently scraped to collect a sample of cells. These cells are placed on a glass slide and stained with dye, so that they can be easily viewed under a microscope. If any cells appear abnormal, a deeper biopsy will be performed.

Dental exam

If radiation is part of the treatment plan for oral cancer, a dental exam beforehand is usually recommended.

When teeth or other structures in the oral cavity must be removed, a specialist known as a prosthodontist may make prosthetic replacements to help restore appearance, comfort and function after treatment.


Although most areas of the nose and mouth may be examined without the use of an instrument, doctors may perform an endoscopy to view hard-to-see areas, such as the larynx and behind the nose.

Imaging tests

Computed tomography (CT) scan: A CT scan may provide information about the size, shape and position of any tumors, and also help identify enlarged lymph nodes that may contain cancer cells.

Magnetic resonance imaging (MRI): Commonly, an MRI scan may be used to examine oral cancer. MRIs provide a very detailed view, and may be particularly useful in determining whether or not the cancer has spread, either to other areas in the neck or other regions of the body.

Positron emission tomography (PET): For patients diagnosed with oral cancer, a PET/CT scan may be used to determine whether cancer has spread to the lymph nodes or other parts of the body.

Indirect pharyngoscopy and laryngoscopy

For both of these procedures, the care team may spray the patient's nose or the back of his or her throat with a numbing medicine to avoid pain. Because people diagnosed with oral cancer are also at increased risk for other head and neck cancers, the care team may also examine other areas of the throat or nose.


If the care team suspects the presence of oral cancer, this thorough exam will most likely be performed. If any oral tumors are found, the care team will remove samples to be examined under a microscope.


An X-ray of the chest may be taken to determine whether the cancer has spread to the lungs. Cancer will not be present in the lungs unless it has advanced. If the result is abnormal, further tests will be performed.

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