4 in 10 cancer cases can be prevented, smoking is top avoidable cause: WHO

Close to four in 10 cancer cases worldwide can be prevented, if people avoided risk factors such as tobacco, alcohol, and physical inactivity, the World Health Organisation (WHO) said on Feb. 3.

The findings came from a new global study from the WHO and its International Agency for Research on Cancer (IARC), using data from 185 countries and 36 cancer types.

They found that about 37 per cent of all new cancer cases in 2022 — around 7.1 million cases — were linked to preventable causes.

This shows that prevention has enormous potential in reducing the global cancer burden, WHO said.

Preventable causes

The study analysed 30 factors that are known to increase the risk of cancer and yet can be avoided.

They include smoking tobacco, drinking alcohol, a high body mass index (BMI), physical inactivity, air pollution, and ultraviolet (UV) radiation.

While most of them are lifestyle choices, the study also looked at nine cancer-causing infections including human papillomavirus (HPV) and hepatitis B.

The biggest preventable contributor to cancer was tobacco, responsible for 15 per cent of all new cases worldwide.

It was followed by infections and alcohol consumption, behind 10 and three per cent of new cases respectively.

The most preventable types of cancer were lung, stomach, and cervical cancer.

Lung cancer was primarily linked to smoking and air pollution, and the other two to different infections.

Gender differences

The report also highlighted some differences in the potential of cancer prevention between genders.

More men get cancer that could have been prevented, making up 45 per cent of new cases in 2022 compared to 30 per cent among women.

This gap was partly because smoking accounted for more men's cancer cases than women's, according to the study.

In Southeast Asia, about 45 per cent of men's cancer cases were preventable in 2022, while only about 25 per cent of women's were.

Smoking was overwhelmingly the biggest preventable cause among Southeast Asian men, accounting for about 25 per cent of new cases that year.

For the women, infections came up top, responsible for over 15 per cent of new cases in 2022, followed by smoking at less than five per cent.

Based on the findings, the WHO urged more context-specific prevention strategies.

They include strong tobacco control measures, alcohol regulation, vaccination against cancer-causing infections, improved air quality, safer workplaces, and healthier food and physical activity environments.

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