Oral cancer

What is oral cancer?

The oral cavity comprises the lip, tongue, lining of the cheeks, gums, floor of the mouth and roof of the mouth, the hard palate and soft palate; while the tonsils, back of the tongue (base of tongue/epiglottis) and mouth (posterior pharyngeal wall) collectively form the oropharynx.

Malignant growths in the oral cavity and the oropharynx are called oral cancers. Most of these cancers are of a type called squamous carcinoma, which means they begin on the surface layer of the mouth and can spread if left untreated. Other types, such as adenocarcinomas, lymphomas and melanomas, may also occur.

Every year in the UK about 5,400 people are diagnosed with oral cancer. About one-third of these will die because of the condition.

Oral cancer is more common in men and is diagnosed most frequently in people over 60, but it's rising in people under 40, particularly young people, due to alcohol intake or exposure to HPV (thought to play a part in causing sexually transmitted infections such as genital warts and cervical cancer).

Oral cancer symptoms

The most common symptoms of oral cancer are:

• An ulcer in the mouth that doesn't heal or bleeds easily on touch
• Persistent pain in the mouth or throat

Less common symptoms are:

• Lump in the mouth, tongue or throat
• Difficulty in opening the mouth or chewing
• Difficulty or pain when swallowing
• Pain going from the mouth or throat into the ear
• Persistent white or red patches in the mouth

Oral cancer risk factors

• People smoking tobacco are more than three times at risk of developing oral cancer, compared with non-smokers. In particular, chewing tobacco is also associated with high rates of oral cancer - this type of exposure is more common in the south-Asian population and the Indian subcontinent (because of the intake of paan).
• Consumption of alcohol increases the risk. It's the quantity of alcohol consumed rather than the type that's linked to the increased risk (consumption of two 125ml glasses of wine doubles the risk). A combination of regular use of alcohol and tobacco is far greater than just the added risk of each on its own.
• HPV is a common virus that is sexually transmitted and is known to cause cancers of the cervix, vulva and anus. Recent studies have shown a relationship between a type of HPV and throat cancer, especially in non-smokers and young adults.
• The risk of lip cancer is increased by sun exposure.
• People with previous lung, gullet and head and neck cancers are at increased risk. This is thought to be because of damage to the lining of the mouth cavity and by exposure to smoking and alcohol (which may have caused the previous cancer).
• Medicines that depress the defence or immune system for conditions such as kidney transplant appear to increase the risk. The risk is also increased in conditions which suppress the immune system, such as AIDS.

As with most cancers, fruit and vegetable intake appears to decrease the risk of oral cancer.

Diagnosing oral cancer

Most oral cancers are diagnosed after one or more of the symptoms listed above have developed, although occasionally some cancers may be detected during routine dental visits. Once a malignant lesion is suspected an urgent referral to an ear, nose and throat specialist, or unit specialising in head and neck cancer should be made by the GP/physician who has first seen the patient.

The initial assessment includes a thorough examination of the mouth, throat and neck both visually and with a fine flexible telescope (nasendoscope) to assess the problem and obtain some tissue from the suspected area. This may take the form of a biopsy (usually done under anaesthetic) or a fine needle aspirate (FNA) of a lymph gland if it's enlarged.

If the diagnosis of cancer is confirmed by the biopsy, further scans may be required to:

• See if the cancer is operable (usually with an MRI scan of the head and neck)
• Find out if the cancer has spread elsewhere either to the lymph glands or lungs (this is usually done with a CT scan of the chest/lungs or a chest x-ray)

Further decisions regarding treatment are discussed in a multidisciplinary meeting among the surgeons, oncologists, radiologists and pathologists. They will study the results of the scans and biopsies to finalise treatment that offers the best chance of cure, and the best function after treatment. Often these two objectives may be at opposite ends of achievability.

Oral cancer treatments

Treatment options include:

• Surgery - to remove the tumour and any lymph glands (neck dissection) it may have spread to.
• Radiotherapy - focused high-energy x-ray treatment of the tumour (or tumour bed) and lymph glands. This area of medicine has seen several new technical innovations, such as IMRT (where precise doses of radiation are administered, with less affect on healthy areas), which results in fewer long-term side effects. Radiotherapy can be given after surgery or with chemotherapy to improve cure rates. Part of the process involves making a plastic shell of the patient to hold the chin and shoulders in a fixed position during the treatment.
• Chemotherapy - involves giving drugs in a drip into a vein can be combined with radiotherapy to cure advanced tumours. By itself, chemotherapy is not curative in oral cancer, but can be used to control the cancer if it has spread to the lungs or other areas.

Treatment of oral cancer can result in severe morbidity, such as facial disfigurement, swallowing difficulties, speech problems, dental problems and/or long-term dryness of the mouth because of lack of saliva.

Managing the side effects and toxicities of the treatment requires close cooperation between the clinicians and speech and swallowing therapists, dentists, nutritionists, dieticians and specialist nurses to proactively manage problems that arise before, during and after the treatments.