Why oral cancer is spreading Friday, October 04, 2002 This is Oral Health Month. For at least a hundred years, medical students have been taught that cancer of the mouth — oral cancer — is a disease of older people, and that men develop it very much more often than women. It was perceived as a scourge that affected those who had both drunk and smoked too much for too long. It was also thought that poorly maintained, rough and ragged teeth contributed to the problem, but it is now several years since dental causes were believed to be an important aetiological factor. The pattern of oral cancer is changing. No longer do five men develop it for every woman: now it is only twice as common in men, and the gender gap is closing. Nor is oral cancer still overwhelmingly a disease of late middle age and beyond. In the past ten years in Scotland, for instance, there has been an almost 50 per cent increase in incidence among the under-45s, and in the past 40 years a fourfold increase in younger patients suffering from it. There has also been a change in the part of the oral cavity most commonly affected. Cancer of the tongue, once rare, has increased in the under-40s by 60 per cent in 30 years. When I qualified, the classic lesion in oral cancer involved the lip, an unsightly advanced ulcer that had grown on a lip that had clasped a Woodbine or a pipe for years. Although the incidence of lip cancer has fallen, this has been more than compensated for by an increase in tongue cancer — particularly in men — and of the floor of the mouth in women. Oral cancer used to be much more common among the poor and disadvantaged, yet it is now seen increasingly in the professional classes. This shift has not been fully explained. No longer can it be assumed that the stereotypical oral cancer sufferer is an elderly, poor man, addicted to his pipe and whisky, who was a reluctant visitor to the dentist. This cancer now affects all classes, both sexes and all age groups — one of the reasons why dental check-ups should be routine. The key to treating oral cancer successfully is early diagnosis. Anyone who has a white sore or a lump, or any persistent sore or ulcer in the mouth, should tell their doctor or dentist. In 1996, a research trust was established in Peeblesshire in memory of Ben Walton, who had died in his twenties from cancer of the mouth. Earlier this year the Ben Walton Trust and the Scottish Oral Cancer Action Group held a sympos-ium at the Royal College of Surgeons in Edinburgh at which Professor Saman Warnakulasuriya, of King's College London, and David Soutar, a consultant plastic surgeon at the Canniesburn Hospital, Glasgow, discussed the results of a three-year study into mouth cancers in the under-45s. Warnakulasuriya has also recently reviewed the risk factors for cancers of the oral cavity in young people in the journal Oral Oncology. The review confirmed the importance of smoking, particularly when combined with excessive drinking, in the causation of oral cancers. This combination increases the risk dramatically, whereas an excessive alcohol intake alone is not so dangerous. Three quarters of the cases could be attributed to this cause. Twenty-five per cent of the patients were non-smokers who had not persistently drunk to excess. And in the study, as many as 30 per cent of the younger people had never smoked, and only six of these non-smokers could have been described as heavy drinkers. Research workers studied the lifestyles, diet, sex life, medical history and family history of the patients whose cancer could not be attributed to tobacco and alcohol. The patient's previous general health, and in particular any oral problems, was important. There was a statistically significant association with anaemia and glandular fever, as well as with sexually transmitted disease. Oral thrush and lichen planus were oral diseases which also seemed to be relevant. This survey, unlike research done at the Sloan-Kettering Cancer Centre in New York, revealed no association between oral cancer and cannabis smoking, whereas the American survey showed a dramatic and disturbing link between cannabis smoking and oral cancers. Andrea Thompson wrote in the journal Scottish Dentist about the discussion at the symposium that followed the contributions of Warnakulasuriya and Soutar. The latter attracted the attention of, and even alarmed, some of the audience by his suggestion that one area which needed further research was the possible connection between oral cancer and oral sex. He said that unfortunately it was difficult to find people who were willing to discuss their sexual behaviour, but that even so, we had to consider the possibility of viruses, including those associated with sexually transmitted diseases, in its causation, as there was an increase in oral cancer in women who neither drink nor smoke. HPV (the wart virus) is a possible candidate, as it already known to cause cancer of the cervix. However, Soutar thought that much of the increase in the incidence of the cancer in women could be attributed to changing social patterns, as women nowadays not only visit pubs as often as men, but drink and socialise as much as they do. They also smoke more than they used to.

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