Oral Cancer

Executive Summary

Risk factors

Most cases of oral carcinoma can be attributed to certain life-style risk factors and are thus preventable. The most important are the use of tobacco and drinking alcohol to excess. Smoking cigarettes in the most commonly encountered risk factor in Europe although any form of tobacco use carries an increased risk. The rising trend in tongue cancer in young men noted previously in some European Union countries (eg. Denmark, UK-Scotland) is thought to be due to marked increases in alcohol consumption. The role of binge drinking has not been adequately investigated.

For some populations in Asia (and migrants arising therefrom) regular areca nut (betel quid) use is relevant.

For those with no tobacco or alcohol habits (up to 25% of younger cases) Human papillomavirus (HPV) infection may be an important risk factor.

Healthy diet can help guard against oral cancer. Fresh yellow-green vegetables and fruits have been identified as beneficial dietary components. These act as antioxidants.

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Clinical presentation

a) Cancer

Signs and symptoms of oral cancer should be understood by the dental practitioner and the wider dental team and all members should receive updating on recognition of key complaints and early stages.

Oral ulcers that fail to resolve within two weeks after appropriate therapy and any new growths for which no other diagnosis can be established should be considered possibly cancerous, until proven otherwise by a biopsy or a specialist examination.

Cancer could also present as a red patch or a red and white mixed lesion, particularly when associated with symptoms.

Presence of induration (hardness at the margins or base) is a key clinical sign of malignancy.

b) Precancer (Potentially malignant disorders)

Disorders of the oral mucosa which on biopsy may be dysplastic but not frankly malignant, may clinically present in a number of ways:

Leukoplakia – ‘The term leukoplakia should be used to recognize predominantly white plaques of question­able risk having excluded (other) known diseases or disorders (that present as white patches) that carry no increased risk for cancer’. It is recommended that the term be used as a clinical diagnosis.

Erythroplakia – a red lesion (defined in a similar way to Leukoplakia, except it is red) for which there is no other attributable cause. This is a dangerous sign that needs urgent investigation.

An erythroleukoplakia (also called speckled leukoplakia) has combined red and white elements in the plaque together with an irregular surface texture.

Oral submucous fibrosis presents as a loss of elasticity of the mucosa, with fibrous bands causing limitation of opening of the mouth.   Early signs may include blanching of the mucosa, a leathery feeling and presents with burning symptoms at meal times.

Other rare forms of potentially malignant disorders are lupus erythematosus, tongue lesions in tertiary syphilis and actinic keratosis of the lip.

The prevalence and the distribution of oral site of a carcinoma may vary within Europe. For example, actinic keratosis of the lip is encountered more often in Southern Spain.

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Diagnostic Aids

Biopsy is essential to establish diagnosis of lesions suspected of cancer. In those thought to be precursor lesions it is important to exclude malignancy and to estimate the grade of epithelial dysplasia by microscopy, the dysplasia grade has some value for predicting malignant potential.

Ploidy analysis and detecting aneuploidy has been shown to be particularly helpful in distinguishing high-risk lesions. A brush biopsy (i.e transepithelial sample) is adequate to harvest epithelial cells for ploidy analysis.

Adjuncts to conventional methods of detection include:

  • Toluidine blue test
  • Chemiluminescence
  • Autofluorescence

The utility of these tests in primary care has yet to be established.

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Primary prevention (including tobacco control)

The major risk factors for oral cancer are well understood. The preventive approach is therefore clear. Medical practitioners have practice protocols to deal with smoking cessation and may have a trained nurse to help their patients. Dental practitioners should similarly provide brief advice to their patients on tobacco cessation and also refer cases to a smoker’s clinic for additional assistance.

There are five crucial steps in motivating people to stop smoking, known as the “5 A’s”:

  1. Ask
  2. Advise
  3. Assess
  4. Assist
  5. Arrange

The 5 A’s provide a scheme for practitioners in a clinical setting to undertake smoking cessation. The practitioner may refer to other useful resources (tobacco-oralhealth.net) for more information on this topic.

Other cancer prevention approaches relate to alcohol moderation (to drink within recommended guidelines). A “drinks meter” is a tool developed to measure up alcohol consumption (drinksmeter.com). Quitting betel quid use and improving diet (by increasing the consumption of fruits and fresh vegetables rich in antioxidants) are also important. Providing such advice should be undertaken in the primary care setting.

Dentists should give advice to patients about their awareness of oral cancer so that they can recognise the signs and symptoms during self-examination of their mouth during home care.  If some change is noted the patient should immediately return to his/her dentist.

Secondary prevention (screening)

Screening and oral mucosal examination are both elements of routine dental practice (oral health examination).

A thorough systemic examination (opportunistic screening) of the oral mucosa is mandatory every time a dentist starts on a course of treatment or at regular reviews. A routine which is comprehensive, effective and should not take more than three minutes to perform is described and illustrated at section “How to look for it“.

Screening helps in earlier diagnosis thus reducing mortality. A significant reduction in mortality among the screened groups who had risky lifestyles has been demonstrated in a randomised control trial in India. The detection of OPMDs allows appropriate interventions to reduce their malignant transformation.

Tertiary Prevention

Removal (excision) of leukoplakia, erythroplakia or erythroleukoplakia will reduce future risk of cancer but will not completely eliminate that risk. Tertiary prevention is also concerned with preventing recurrence of a treated cancer or a second cancer occurring in the head and neck or upper aerodigestive tract.

Treated patients should be monitored regularly to screen for the possibility of new lesions (diagnostic adjuncts are recommended for surveillance) and advised on risk factors if these are continuing.

Patients on surveillance should be provided ‘walk in’ access to specialist clinics to return sooner if they notice any new symptoms associated with their disease.

Public Awareness

Oral cancer is often poorly understood by society in general. The symptoms are not widely known and are frequently ignored in the early stages when it is most amenable to treat.

Population surveys amongst adults suggest only about half have heard about oral cancer.  A study among young people diagnosed with mouth cancer indicates they often ignore the first symptoms and delay asking help for several months.  For more information on improving public awareness see examples of activities by the British Dental Health Foundation, UK and activities in the Republic of Ireland at mouthcancer.org and mouthcancerawareness.ie.

Role of primary health care dentists, doctors, pharmacists & hygienists

Primary care practitioners can play a key role in both advising their patients about risk factors and case detection.

Dentists are important in the early detection through opportunistic screening and organised screening of populations at high risk.

Dentists should take a leadership role in professional educational activities in their local regions.

Physicians can attempt a targeted approach on smokers and heavy alcohol drinkers.

Dental hygienists should bring to the attention of the supervising dentists any suspicious lesions they might notice during hygiene visits.

Pharmacists have a role to play in smoking cessation and also in directing patients with non healing ulcers who ask for OTC medications to see a dental/medical practitioner.

Medicolegal aspects

Concern should be aroused by any persistent oral mucosal condition that does not respond to conventional simple measures such as eliminating sharp cusps or a short 7 day course of antifungal treatment.

Any delay can have life threatening consequences for the patient that might lead to allegations of negligence. Effective management should follow best clinical practice such as that provided by this resource, keeping abreast with any published updates. This should be backed up with accurate and appropriate record keeping.

A good response to simple treatment given by a dentist is a useful indicator of recovery, and that the suspicious area was not a malignant lesion.  If the area has not fully resolved with attention to possible causes, an urgent referral should be made and clinical notes updated.

For a non-healing ulcer in the oral cavity, trying various local therapies, one after another, simply adds to delay and worsens chance of patient’s survival.

Referral

If oral cancer is suspected the referral must be marked “Urgent”. Urgent referrals should be faxed to the local hospital. In the UK suspected cancers are referred under the 2 week (2 ww) referral guidelines issued by NICE/SIGN.

Other referrals should be categorised as non-urgent or prompt.

Potentially malignant disorders should be referred to a specialist following a mucosal examination for assessment (including biopsy) and advice on management.

Urgent referral of suspected cancers should save lives. Each European Union country should develop guidelines for urgent referral of head & neck cancers. You can find more information at section “How to refer“.

Recent Advances

Cancer is a genetic disease, particularly due to DNA aberrations caused by carcinogens.

It is possible to analyse tissue, body fluids (increasingly including saliva) for markers of aberrations in chromosomes, genes or their protein product in patients with cancer or precancer.

Loss of sections of specific chromosomes (eg. 3p, 9p and 11q) that harbour tumour suppressor genes or mutations that increase the risk of cancer are now known. Any change of ploidy status can also be assessed from a standard biopsy or a brush biopsy.

It is not known precisely how many hits or chromosomal aberrations are necessary to render a clone of cells malignant. Recent research of the above kind and on signalling pathways led to genetic models for explaining the development of head and neck cancer and future potential for biomarker development to assess cancer risk. Therapeutic targets are being pursued and Phase III clinical trials are underway to individualise treatment for cancer.

Key messages

  • Oral cancer can be lethal
  • It is becoming more common worldwide, no age group is immune.
  • Knowledge regarding major risk factors is well established: Oral cancer can be prevented
  • Small lesions are easier to treat: Mucosal disorders suspected to be malignant should be referred to a specialist without delay.
  • Opportunistic screening may allow identification of asymptomatic early disease that may reduce morbidity.

Additional resources

This education resource is based upon ‘Early Detection and Prevention of Oral Cancer‘, an e-learning program based on the research and training material produced by Professor Saman Warnakulasuriya, Department of Oral Medicine, King’s College Hospital, and cosponsored by the Department of Health (UK). This e-learning program was first distributed to the UK dentists on a CD-ROM.  An extended version is available at Oral Cancer Eductaion and Research Centre.

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