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Doctor examining patient's throat for cancer

Oral cancer—the most common type of head and neck cancer—occurs when a malignant (cancerous) growth develops in a part of the mouth, such as the:

  • Lips
  • Gums
  • Tongue
  • Floor of the mouth (underneath the tongue)
  • Roof of the mouth
  • Inside lining of the cheeks

Signs of oral cancer are often spotted by dentists during routine teeth cleanings. If a dentist believes a suspicious growth may be malignant, he or she may refer the patient to a cancer specialist, a head and neck surgeon or an otolaryngologist (ENT doctor) for further evaluation. 

How is oral cancer diagnosed?

A physician may use one or more of the following procedures to rule out oral cancer or confirm a diagnosis:

  • Biopsy. A biopsy is a minimally invasive procedure that involves removing a small amount of suspicious tissue from the mouth, usually under local anesthesia in an outpatient setting. The tissue is then examined underneath a microscope for cancerous or precancerous cells.
  • Imaging scans. There are multiple imaging scans that can be used to assist in the diagnostic process, including computerized tomography (CT) scans and magnetic resonance imaging (MRI) scans that provide clearer pictures of the oral cavity than traditional X-ray imaging.
  • Endoscopy. An endoscopy procedure involves inserting a thin, lighted scope into the mouth to examine hard-to-see areas toward the back of the oral cavity and into throat.

Once oral cancer is diagnosed, the next step is to stage the cancer and determine an appropriate course of treatment. Oral cancer is staged from 1 to 3 according to the size of the primary tumor, with 3 being the most advanced stage.

How often should you have an oral cancer screening?

Identifying oral cancer in an early stage can improve the likelihood of successful treatment and a positive quality of life. For this reason, many dentists and physicians recommend oral cancer screening every three years for adults ages 20 through 40. Individuals older than 40 should be screened on an annual basis, while people with oral cancer risk factors (such tobacco use, human papillomavirus (HPV) infection and/or heavy alcohol consumption) should be screened annually regardless of their age. It’s also recommended for adults to conduct monthly oral cancer self-exams and promptly report any white patches, lumps, sores or other unusual changes to their dentist or physician.

What does oral cancer screening involve?

An oral cancer screening begins with a clinical exam of a patient’s mouth and throat. This will involve assessing the roof of the mouth, tongue, tonsils, gums and inner cheeks for abnormalities like lumps, discolored patches and swelling. The clinician performing the screening will also gently feel around the jaw, the neck, under the chin and the outside cheeks to identify any unusual masses or firm nodules.

If a patient’s dentist detects any possible signs of precancerous or cancerous lesions, he or she may use a special dye and/or light to further examine the mouth. Some common testing methods involve:

  • Using a laser light that illuminates abnormal tissue differently than healthy tissue
  • Rinsing the mouth with an acetic acid solution and then using a special light to assess the abnormal area
  • Placing toluidine blue dye over the suspicious area, which will turn blue if abnormal tissue is found

Oral cancer diagnostics at Moffitt

Moffitt Cancer Center’s Head and Neck Oncology Program offers  world-class diagnostics and cancer treatment. To request an appointment at Florida’s top cancer hospital, contact Moffitt at 1-888-663-3488 or submit a new patient registration form online. A referral is not required. We’re streamlining access to advanced cancer care by connecting patients with physicians in 24 hours or less.


American Cancer Society: About Oral Cavity and Oropharyngeal Cancer  
CDC: Oral Cancer and HPV Vaccine/


Oral Cavity (Mouth) Cancer