Diagnosis of oral cancer

Diagnosis is the process of finding out the cause of a health problem. Diagnosing oral cancer usually begins with a visit to your dentist or family doctor. Your dentist or doctor will ask you about any symptoms you have and do a dental or oral exam. Based on this information, your dentist or doctor will refer you to a specialist, such as a head and neck surgeon. A head and neck surgeon is also called an ENT (ear, nose and throat) doctor or an otolaryngologist. The head and neck surgeon or ENT doctor will do other exams and tests.

The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as oral cancer. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of oral cancer.

The following tests are usually used to rule out or diagnose oral cancer. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has progressed). Your doctor may also order other tests to check your general health and to help plan your treatment.

Health history and physical exam

Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. Your doctor will ask questions about your history of:

  • symptoms that suggest oral cancer
  • tobacco use
  • alcohol use
  • sun and ultraviolet (UV) exposure
  • human papillomavirus (HPV) infection
  • previous cancer
  • weight loss
  • other medical conditions

Your doctor may also ask about a family history of:

  • head and neck cancers
  • other cancers

A physical exam allows your doctor to look for any signs of oral cancer. During a physical exam, your doctor may:

  • assess facial symmetry, speech, swallowing, breathing and hearing
  • carefully look at the mouth
  • feel for lumps or swelling on the inside of the mouth, including the cheeks and lips
  • feel the floor of the mouth, tongue and roof of the mouth
  • check tongue movements
  • feel the neck for any lumps or swelling
  • check the salivary glands
  • look at the throat using an endoscope

Find out more about physical exams.

Exfoliative cytology

Exfoliative cytology is a test used to look for abnormal or cancerous cells. The doctor or dentist uses a cotton swab, brush or small wooden stick to scrape a small sample of cells from an area and places them on a glass slide. They stain the sample with dye and examine it under a microscope. This test can detect cell changes and may show that further tests are needed. If an abnormality is found, doctors may do a biopsy.


During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. Doctors sometimes apply dye to an abnormal area in the mouth (such as an area of leukoplakia or erythroplakia) to help them see the biopsy site more clearly. A report from the pathologist will show whether or not cancer cells are found in the sample.

Punch biopsy removes a round part of the growth using a sharp tool called a punch. It is the most common type of biopsy used to sample the inner lining (mucosa) of the mouth. A special instrument is used to collect a biopsy sample from an ulcer or lesion.

Incisional biopsy removes a small piece of tissue from the abnormal area using a scalpel (knife).

Fine needle aspiration (FNA) uses a very thin needle to remove a small amount of fluid or cells from the abnormal area. FNA may be used to biopsy lumps or lymph nodes in the neck. An ultrasound or a CT scan may be used to guide the needle for FNA.

Find out more about biopsies.


An endoscopy is done when diagnosing and staging oral cancer. It allows a doctor to look inside the body using a flexible tube with a light and lens on the end. This tool is called an endoscope.

Different types of endoscopy may be used to find small tumours or to see if cancer has spread beyond the mouth or if there are other tumours anywhere in the head or neck.

Nasopharyngoscopy may be used to look inside the nose and throat (pharynx).

Laryngoscopy may be used to look at the voice box (the larynx).

Panendoscopy may be used to look at the pharynx, larynx, esophagus, windpipe (trachea) and bronchi.

Find out more about an endoscopy.

Nutritional assessment

People diagnosed with oral cancer usually have serious nutrition problems. Good nutrition is especially important for people who have cancer because it helps to ensure that you are healthy enough to have and recover from treatment.

A dietitian will give you a nutritional assessment when you are diagnosed and during your treatment by looking at your body mass index (BMI), what you are eating and any weight changes. You may need to have a feeding tube placed so your nutrition can be good enough to support your treatment. Find out more about tube feeding.

Speech, swallowing and dental assessments

People diagnosed with oral cancer may already have dental problems and problems with speech or swallowing. It is important to have a complete dental exam and have any necessary dental work done before treatment such as radiation therapy.

You will see a speech therapist (speech-language pathologist) at diagnosis and throughout treatment to help manage any speech or swallowing problems you may have as a result of oral cancer or its treatment.

You may also have one of the following tests to see if you are having any problems with swallowing.

Fibre optic endoscopic evaluation of swallowing (FEES) uses a special endoscope with a fibre optic camera to look at the pharynx and larynx while the person swallows.

Video fluoroscopic swallow study (VFSS) (also called a modified barium swallow) uses x-ray and a contrast medium (barium) to record swallowing movements.


An x-ray uses small doses of radiation to make an image of parts of the body on film.

Chest x-ray may be used to check if cancer has spread to the lungs.

Panoramic x-ray of the mouth (also called a panorex) may be done to assess the teeth and see if cancer has spread to the jaw. This x-ray takes pictures of the upper and lower jawbones and surrounding area.

Find out more about x-rays.


An ultrasound uses high-frequency sound waves to make images of parts of the body. It is used to check if cancer has spread to the lymph nodes in the neck (called cervical lymph nodes) or to major blood vessels in the neck, such as the carotid arteries. Ultrasound may also be used to guide an FNA biopsy.

Find out more about ultrasounds.

CT scan

A computed tomography (CT) scan uses special x-ray equipment to make 3-D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

A CT scan is used to provide information about the size, shape and location of a tumour. It can also be used to see if cancer has spread to the lower jawbone or lymph nodes in the neck. A CT scan of the chest can also be used to see if cancer has spread to the lungs. Some surgeons routinely perform a CT scan of the neck and the chest before surgery.

Sometimes a contrast medium is used with a CT scan to help show better detail. It is usually injected into a vein in the hand or arm.

Find out more about CT scans.


Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-D pictures.

An MRI is used to provide information about the size, shape and location of a tumour. It is often used after a CT scan to get additional information. It can be used to assess the soft tissues of the head and neck. It can also be used to measure how deep a tumour has grown into a structure in the mouth or see if the tumour is spreading along a nerve. MRI can be used to see if cancer might have spread to the lymph nodes in the neck.

Find out more about MRIs.

PET scan

A positron emission tomography (PET) scan uses radioactive materials called radiopharmaceuticals to look for changes in the metabolic activity of body tissues. A computer analyzes the radioactive patterns and makes 3-D colour images of the area being scanned.

A PET scan is used to see if the cancer has spread to lymph nodes or other parts of the body. It may be combined with a CT scan (called a PET-CT scan).

Find out more about PET scans.

Heart and lung function tests

The doctors may order heart and lung function tests to check how well the heart and lungs are working and make sure you are healthy enough to have and recover from surgery or anesthesia. An electrocardiogram (ECG) measures the electrical activity in the heart. An echocardiogram (echo) uses ultrasound to look at the structure and motion of the heart.

Lung function tests (also called pulmonary function tests) measure how much air your lungs can hold and how well you can let the air out of your lungs.

Find out more about ECG, echo and pulmonary function tests.

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about a diagnosis.

Expert review and references

  • Alberta Health Services. Oral Cavity Cancer Clinical Practice Guideline HN-002. Alberta Health Services; 2016.
  • American Cancer Society. Oral Cavity and Oropharyngeal Cancer. 2016.
  • American Society of Clinical Oncology. Oral and Oropharyngeal cancer. 2016: http://www.cancer.net/.
  • Cancer Care Ontario. Evidence-Based Series 5-3: The Management of Head and Neck Cancer in Ontario. 2009.
  • Cancer Research UK. The Mouth and Oropharynx. Cancer Research UK; 2016.
  • Koch WM, Stafford E, Chung C, Quon H . Cancer of the oral cavity. Harrison LB, Sessions RB, Kies MS. Head and Neck Cancer: A Multidisciplinary Approach. 4th ed. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2014: 16A:335-356.
  • National Cancer Institute. Lip and Oral Cavity Cancer Treatment (PDQ®). 2016.
  • National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers (Version 1.2015). 2015.
  • Richardson,M.S., Barnesw,L., Carlson,D.L., et al . Protocol for the Examination of Specimens from Patients with Carcinomas of the Lip and Oral Cavity . College of American Pathologists . College of American Pathologists . Northfield, IL : College of American Pathologists ; 2009 .
  • Scully C, Bagan JV, Hopper C, et al . Oral cancer: current and future diagnostic techniques. American Journal of Dentistry. 2008.

Medical disclaimer

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