Watch Your Mouth

If routine screening is the best defense against oral cancer, why aren’t more doctors offering it?

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By  Dr Vinod K Joshi Published  August 16, 2006

If routine screening is the best defense against oral cancer, why aren’t more doctors offering it?

Mouth cancer shown in the right buccal mucosa. Cancer can occur in any part of the mouth, tongue, lips, throat, salivary glands, pharynx, larynx, sinus, and other sites located in the head and neck area.

Oral and pharyngeal cancer is the sixth most common malignancy reported worldwide, and one with high mortality ratios among all malignancies. The global number of new cases is estimated at 405,318 annually, with about two-thirds of them arising in developing countries.

The proportion of deaths per number of cases is markedly higher from oral cancer than breast cancer, cervical cancer or skin melanoma, and this is largely due to late diagnosis. Yet the precursor tissue changes that lead up to a malignancy are visible to the naked eye, making them an easy target for identification. So the question is, why are early detection rates so low?

One answer may be poor screening rates. A recent study of primary care medical practitioners revealed that many GPs felt routine head and neck screening should fall to dentists. But in countries such as the UAE, where only a minority of residents undertake regular visits to the dentist, it’s easy for high-risk patients to fall through the net.This is particularly concerning as the incidence of risk behaviour, such as smoking and alcohol consumption, is highest among lower socio-economic groups that are least likely to visit the dentist.

The number of cases of mouth cancer in Middle Eastern countries is significant, but the situation is not getting the attention it deserves. Implementing opportunistic screening in a primary care setting, alongside education on risk factors, could increase early discovery of lesions and have a positive impact or morbidity and mortality.

People who smoke and drink face a 38% greater risk of developing oral cancer|~|Men are twice as likely to develop oral cancer than women, and those aged 40 or over are most at risk. However, while gender and age play a role in the development of oral cancer, lifestyle choices have the most significant influence.

Tobacco is the predominant risk factor for mouth cancer. According to the American Cancer Society, 90% of patients diagnosed with oral cavity and oropharyngeal cancer are tobacco users.

Among the World Health Organisation regions, the Middle East has one of the highest smoking rates, with nearly two-thirds of men regular smokers. But there is hope: stopping smoking leads to a rapid reduction in risk of the disease – a fall of 50% within five years – and after ten years, the risk approaches that of life-long non-smokers.

In the list of risk behaviours, alcohol consumption comes a close second, particularly for those who consume more than four units a day. The World Cancer Research Fund recommends that patients at risk avoid alcohol entirely. If abstinence is not an option, than guidelines indicate that men should consume less than two alcoholic drinks a day, and women less than one.

The combined effect of tobacco and alcohol on mouth cancer risk is much greater than that of either factor on its own. People who combine tobacco and excessive alcohol use face a 38% greater risk of developing oral cancer than those who abstain from both products.

Aside from the risk factors of smoking and chewing tobacco, oral cancer occurs more frequently among people who chew areca nuts in betel quids, such as paan and gutka.

This is a common practice among the immigrant worker population in the Middle East from Pakistan, Bangladesh, India and other countries in the region, where its use is culturally bound. Packaged betel mixtures, known by several names, are widely available in Asian countries and regions of the world with large populations of Asian immigrants.

Recent findings have also suggested a link between oral cancer and the human papilloma virus (HPV). While HPV has long been known to cause cervical cancers, researchers now believe the virus could be behind a small, but significant, group of oral cancer cases that cannot be attributed to excessive tobacco and alcohol use, either because the patients are too young or because they do not smoke. Researchers suspect the virus is transmitted through oral sex.

A study conducted by Dr No-Hee Park showed that the mouth was, at the cellular level, structurally very similar to the vagina and cervix. Both organs have the same type of epithelial cells that are the target of HPV 16 and HPV 18.

Dr Park also showed that smoking and drinking alcohol promotes HPV invasion. A more recent study, conducted by Dr Maura Gillison at the Johns Hopkins Oncology Center, revealed that in 25% of 253 patients diagnosed with head and neck cancers, the tissue taken from tumours was HPV positive. HPV 16 was present in 90% of these positive tissues. With the advent of cervical cancer vaccines, oral infection may be avoided in the future.

Although there have been significant improvements in chemotherapy and surgical techniques, oral cancer remains particularly challenging to treat since most patients present with advanced disease, have secondary tumours and suffer from other co-morbidities. Over 60% of all patients present with late lesions when the prognosis is already poor and metastatic spread has occurred.

Treatment at a late stage causes problems with speech, eating, swallowing, taste and appearance, resulting in greater disability than is associated with other cancers.

Very few people know the early warning signs for mouth cancer, with many patients tending to view oral mucosal abnormalities, such as long-standing ulcers and white patches, as unimportant and treatable with over-the-counter products. Most people don’t realise that a persistent mouth ulcer can be an early sign of mouth cancer when, in fact, it is one of the most common symptoms.

Sadly, this delay in diagnosis means their condition is much harder to cure and treatment is more debilitating. To have any hope of improving this, it is vital for healthcare professionals to educate patients on the risk factors and symptoms of oral cancer.

If oral cancer is detected early, survival rates are in the 80-90% range. Late stage detection yields less than a 30% survival rate. Patients should be encouraged to examine their mouth regularly, particularly if they are at high-risk.

A high index of suspicion is a prerequisite for early diagnosis and referral of patients with oral cancer. The oral mucosa tends to heal itself in two weeks, so any changes to a patient’s mouth that last three weeks or more should be checked out.

Extraoral and perioral tissues should be examined first, followed by the intraoral tissue. Malignant lesions, usually discrete entities located in the high-risk areas of the mouth, are not associated with a specific aetiology, and persist despite removal of local factors. Patients with urgent referral symptoms should be referred to a specialist immediately.

The most common areas for mouth cancer to develop are on the tongue and the floor of the mouth. Individuals that use chewing tobacco are likely to have them develop in the sulcus between the lip or cheek and teeth in the lower jaw.

Cancers of the hard palate are uncommon, though not unknown. The base of the tongue at the back of the mouth, and on the pillars of the tonsils, are other sites where it is commonly found.

The earliest and most consistent clinical presentation of squamous carcinoma is the persistent red (erythroplakia) or mixed red and white (erytholeukoplakia) lesion. This is an innocuous appearing lesion, which is inflammatory, atrophic and shows mucosal alteration, with or without a karatinised component.

Purely white (leukoplakia) lesions, that can’t be rubbed off and arise without apparent cause, are considered to be premalignant, but the rate of change to malignancy in the Western World is comparatively slow with only 0.13 to 6% eventually becoming malignant. Only 6% of early invasive carcinomas or carcinoma in-situ have been shown to be purely white lesions.

The standard appearance of oral cancer is an ulcer with a raised rolled edge, which feels firm on palpation. Unfortunately, this typical presentation is often a late sign of oral cancer.

In some cases the lesion may be raised without ulceration and there may be erythroplakia or leukoplakia associated with the lesion. In some cases of tongue cancer, the ulceration may be posterior and difficult to observe.

In these cases, palpation of the tongue can reveal a mass or thickening, which may confirm the need for urgent referral. Any lesion, whether it looks benign or malignant, should be palpated. Identifiable co-existing risk factors in patients with a lesion should heighten suspicion, but it is important to remember that 25% of mouth cancer patients have no known risk factor.

Health professionals have a key role to play in increasing awareness and early detection.

Patients with lifestyles that put them at risk should be provided with health promotion advice to help them reduce their susceptibility. Leaflets and posters on lowering the risk of mouth cancer are available free of charge to health professionals, and can be used as discussion tools during consultations or displayed in the waiting room (http://info.cancerresearchuk.org/images/pdfs/mc_gp.pdf).

Screenings are quick, painless and cost-effective and can significantly contribute to reducing the death rate of mouth cancer cases. Take the time to educate and screen your high-risk patients. Remember, mouth cancer is both preventable and treatable if found early.

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