One third of mouth cancers caused by smokeless tobacco

A new study from the International Agency for Research on Cancer (IARC)[1] estimates worldwide the share of oral cancers linked to the consumption of smokeless tobacco and betel[2]In 2022, more than 120,000 cases of oral cancer were caused by the consumption of these products, representing a third of oral cancer cases worldwide.

The researchers obtained data on smokeless tobacco and areca nut use from national surveys of the general population in countries around the world. They then linked these data to estimates of the increased risk of oral cancer attributable to smokeless tobacco or areca nut use. They drew on epidemiological studies listed in the recent IARC Handbook on Cancer Prevention Volume 19, which focuses on preventing oral cancer.

Worldwide, it is estimated that 300 million people use smokeless tobacco and 600 million people use areca nut. The highest rates of use are in South Central Asia, Southeast Asia and Melanesia.

Oceania and Asia, the most affected regions

According to the IARC study, published in The Lancet Oncology, 120,000 people diagnosed with oral cancer in 2022 developed the disease because they had used either smokeless tobacco such as snus (found in Nordic countries), naswar (popular in South Asia) and toombak (used in Sudan), or addictive betel nuts, which grow on the Areca palm tree.

More than 95 % of all cases of oral cancer caused by smokeless tobacco and areca nut use occurred in low- and middle-income countries (115 900 cases). The regions with the highest incidence of oral cancer caused by smokeless tobacco and areca nut use are South Central Asia (total 105 500 cases, including 83 400 in India, 9700 in Bangladesh, 8900 in Pakistan and 1300 in Sri Lanka), followed by South-East Asia (total 3900 cases, including 1600 in Myanmar, 990 in Indonesia and 785 in Thailand) and East Asia (total 3300 cases, including 3200 in China).

In Papua New Guinea, more than 77,% of the population currently consume areca nut. Areca nut was responsible for 84% of oral cancer cases in both sexes in 2022.

Men are the main consumers of these products

Globally, an estimated 77 % of oral cancer cases attributable to smokeless tobacco and areca nut use were in men (92 600 cases) and 23 % in women (27 600 cases). In general, the proportions of oral cancer cases attributable to smokeless tobacco and areca nut use were higher in men than in women, except in Southern Africa and South-East Asia. However, the prevalence of smokeless tobacco and areca nut use is higher in women than in men in both regions.

In Bangladesh, for example, betel quid and tobacco use accounted for 67% of oral cancer cases in women and 54% of oral cancer cases in men in 2022.

Have specific prevention policies

The proportion of adults who smoke (combustible tobacco) fell from around 34 % at the start of the millennium to 23 % in 2020. The same reduction was not observed for other tobacco products, notably smokeless tobacco.

According to the researchers, these results demonstrate the need to improve public health measures to dissuade people from using these products, in order to achieve the same reduction as that recorded for combustion products.

The free availability of smokeless tobacco and areca nut and the existence of very strong marketing make them widely consumed products in these countries. The areca nut market in Southeast Asia has been growing steadily over the last two decades.

In India, the areca nut industry has hired Bollywood celebrities to advertise the product as a mouth freshener. Tobacco control experts have been warning for years about the health hazards of areca nut and the sinister product placement by tobacco companies.

"Although tobacco control has improved, prevention of smokeless tobacco use has stalled and areca nut remains largely unregulated"[3], said Dr Isabelle Soerjomataram, deputy head of the cancer surveillance department at the International Agency for Research on Cancer and co-author of the report. “To reduce inequalities, we must prioritize the fight against smokeless tobacco and integrate an areca nut prevention framework into cancer control programs,” she said, noting that the health systems that treat most cases of oral cancer are not necessarily well equipped.

©Generation Without Tobacco

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[1] Global burden of oral cancer in 2022 attributable to smokeless tobacco and areca nut consumption: a population attributable fraction analysis, Rumgay, Harriet et al. The Lancet Oncology, Volume 0, Issue 0

[2] Betel is a preparation combining betel leaves with areca nut and sometimes also with tobacco. It is chewed for its stimulant and psychoactive effects. After it has been chewed, it is spat out or swallowed.

[3] Sarah Newey, One in three oral cancers linked to smokeless tobacco products like snus, The Telegraph, published October 8, 2024, accessed October 9, 2024