Mouth cancer

Dr Johann Kluge explains the causes, symptoms and treatment of mouth cancer.

Mouth (oral cavity) cancer is a subdivision in the head and neck region. The mouth is confined by the anatomical borders that stretch from the lips (anteriorly) to include the tongue, floor of the mouth, cheeks, hard palate and gums (or gingiva).

What is the incidence of mouth cancer?

It’s the 11^th most common malignancy. More than 90% of cancerous growths  in the mouth are squamous cell carcinomas, with the remainder being rarer tumours or tumours developing from the small salivary glands.

Current oral cancer  statistics (US data):

• Overall 10,5 adults per 100 000 will develop mouth cancer.
• The rates for males are significantly higher than for females.
• Rates are higher for Hispanic and African-American males than for Caucasian males.
• Increase of rates with age. The increase becomes more rapid after age 50 and peaks between ages 60 and 70.
• The average age of most people diagnosed is 62 years.
• Rare in children, but a little more than one quarter occur in patients younger than 55.
• Eight in 10 people with mouth cancer are tobacco users.
• According to the National Institutes of Health, nicotine and alcohol together account for around 80% of mouth cancers in men and around 65% of mouth cancers in women.

In the Western world, the tongue and floor of the mouth are the most common sites of origin for primary squamous cell carcinoma. Whereas the retromolar trigonum and buccal mucosa (see image) are most frequently encountered in areas, of the world, where chewing of tobacco and/or   betel nuts are common.

Symptoms of mouth cancer

• Any sore or lump on the lip or in the mouth.
• A white and/or red patch on the gums, tongue, or cheeks.
• Unusual or persistent bleeding, pain, or numbness in the mouth.
• Swelling that causes false dentures to fit poorly or be uncomfortable.
• Any loose teeth without a definite cause.
• Halitosis (persistent bad breath).
• Unexplained weight loss.

Risk factors 

Tobacco

• Eighty percent of people with mouth cancers use tobacco. This includes cigarettes, chewing tobacco or snuff. E-cigarettes have also been proven to cause cancer.

Alcohol

• Seventy percent of people diagnosed with mouth cancer are heavy drinkers. Hard liquor has a higher risk than wine but alcohol has clearly been proven as the second biggest risk factor.

Tobacco and alcohol combined

• Together these have a synergistic effect that increases the risk even further than the two risk factors alone. Studies have shown that people who use tobacco and alcohol together have a substantially bigger risk.

Betel quid and gutka

• Asian countries are well-known for chewable tobacco with betel quid (a leaf from the betel plant) and gutka (a combination of betel quid and tobacco), being the most common and consumed. The use of this, especially, leads to buccal mucosal (cheek) squamous cell carcinoma.

Ultraviolet light

• Cancers of the lip are more common among people with prolonged or chronic exposure to sunlight. 

Other risk factors

• A diet low in fruits and vegetables.
• A weakened immune system.
• Graft versus host disease (GvHD), a condition that sometimes occurs after a stem cell transplant.
• Lichen planus – a disease that often affects the skin.
• Genetic syndromes, such as Fanconi anaemia.

How is mouth cancer diagnosed?

Any suspicious lesion needs to be biopsied. During the biopsy, a small piece of abnormal tissue from the area, where mouth cancer is suspected, is taken and sent for histological evaluation. This entails special staining of the piece biopsied and inspection under microscopic magnification.

In certain conditions, special investigations are made use of to evaluate the extent of the cancer and the presence of possible spreading of the tumour. This entails CT scans, MRIs and/or Panorex (X-rays of the upper and lower jaw).

What is the treatment of mouth cancer?

There are different ways to treat mouth cancer, depending on the location and stage, including:

Surgery still stays the first choice of treatment, with the emphasis not only on removing the whole tumour but restoring the functionality of the involved area.

Radiotherapy makes use of high-energy rays to destroy cancer cells. This can be used as single treatment or in combination with surgery, depending on the extent of the cancerous growth.

Chemotherapy is a variety of medicines used to kill cancer cells. These drugs can be used alone (i.e. lymphoma) or in combination with surgery and radiation, or in palliative cases where cure is unfortunately not feasible.

MEET OUR EXPERT – Dr Johann Kluge

Dr Johann Kluge MBChB (UP), MMed (ENT) (UP) is a head and neck surgeon at Life Groenkloof Hospital as well as one of the consultants, Department of General Surgery, University of Pretoria. He completed a two-year fellowship, in 2016, with the International Federation of Head and Neck Oncologic Societies underwritten by Professor Jatin Shah.