Smokeless Tobacco, Areca Nut Behind 1 in 3 Oral Cancers

Globally, nearly one in three cases of oral cancer can be attributed to use of smokeless tobacco and areca nut products, according to a new study from the International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO).

“Smokeless tobacco and areca nut products are available to consumers in many different forms across the world, but consuming smokeless tobacco and areca nut is linked to multiple diseases, including oral cancer,” Harriet Rumgay, PhD, a scientist in the Cancer Surveillance Branch at IARC and first author of the study in Lancet Oncology, said in a news release.

Worldwide, about 300 million people use smokeless tobacco and 600 million people use areca (also called betel) nut, one of the most popular psychoactive substances in the world after nicotine, alcohol, and caffeine. Smokeless tobacco products are consumed without burning and can be chewed, sucked, inhaled, applied locally, or ingested. Areca nut is the seed of the areca palm and can be consumed in various forms.

“Our estimates highlight the burden these products pose on health care and the importance of prevention strategies to reduce consumption of smokeless tobacco and areca nut,” Rumgay said.

According to the new report, in 2022, an estimated 120,200 of the 389,800 (30.8%) global cases of oral cancer were attributable to these products.

More than three quarters (77%) of attributable cases were among men and about one quarter (23%) among women.

The vast majority (96%) of all oral cancer cases caused by smokeless tobacco and areca nut use occurred in low- and middle-income countries.

Regions with the highest burden of oral cancers from these products were Southcentral Asia — with 105,500 of 120,200 cases (nearly 88%), including 83,400 in India, 9700 in Bangladesh, 8900 in Pakistan, and 1300 in Sri Lanka — followed by Southeastern Asia with a total of 3900 cases (1600 in Myanmar, 990 in Indonesia, and 785 in Thailand) and East Asia with 3300 cases (3200 in China).

Limitations and Action Points

The authors noted a limitation of the analysis is not accounting for the potential synergistic effects of combined use of smokeless tobacco or areca nut products with other risk factors for oral cancer, such as smoking tobacco or drinking alcohol.

The researchers explained that combined consumption of smokeless tobacco or areca nut, smoked tobacco, and alcohol has a “multiplicative effect” on oral cancer risk, with reported odds ratios increasing from 2.7 for smokeless tobacco only, 7.0 for smoked tobacco only, and 1.6 for alcohol only to 16.2 for all three exposures (vs no use).

However, the proportion of people who chewed tobacco and also smoked in countries with high smokeless tobacco or areca nut use was small. In India, for example, 6% of men and 0.5% of women in 2016-2017 were dual users of both smoked and smokeless tobacco, compared with 23% of men and 12% of women who only used smokeless tobacco.

Overall, curbing or preventing smokeless tobacco and areca nut use could help avoid many instances of oral cancer.

Despite “encouraging trends” in control of tobacco smoking in many regions of the world over the past two decades, progress in reducing the prevalence of smokeless tobacco consumption has stalled in many countries that are major consumers, the authors said.

Compounding the problem, areca nut does not fall within the WHO framework of tobacco control and there are very few areca nut control policies worldwide.

Smokeless tobacco control must be “prioritized” and a framework on areca nut control should be developed with guidelines to incorporate areca nut prevention into cancer control programs, the authors concluded.

Funding for the study was provided by the French National Cancer Institute. The authors had no relevant disclosures.