New Delhi: Nearly two in every five cancer cases worldwide in 2022 were likely preventable, as they were linked to modifiable risk factors such as smoking, infections and alcohol, according to an analysis.
Researchers, including those from the International Agency for Research on Cancer, the United Nations’ cancer agency under the World Health Organization, analysed 18.7 million cancer cases in 2022 across 185 countries using the GLOBOCAN database, covering 36 types of cancers.
Lung cancer had the highest share of cases attributable to modifiable risk factors — 1.8 million out of 2.5 million cases — followed by stomach and cervical cancers.
A high body mass index (BMI), insufficient physical activity, sub-optimal breastfeeding and air pollution were among the other modifiable risk factors, showed the findings published in the journal Nature Medicine.
The researchers also found that a higher proportion of cancer cases among men were linked with modifiable risk factors (45.4 per cent of all new cancer cases), compared with women (nearly 30 per cent).
“More than one-third (37.8 per cent), or 7.1 million out of 18.7 million, cancer cases worldwide were attributable to 30 modifiable risk factors, underscoring the critical importance of prevention in reducing the global cancer burden,” the authors wrote.
“Smoking tobacco was the leading risk factor, accounting for 15.1 per cent (3.3 million cases) of all new cancer cases, followed by infections, which contributed to 10.2 per cent (2.3 million cases), and alcohol consumption, responsible for 3.2 per cent (approximately 700,000 cases) of all new cancer cases,” they said.
Infections such as those caused by human papillomavirus (HPV) or helicobacter pylori (causes stomach infection) appeared to be the biggest risk factor for cancers among women around the world, and were linked with 11.5 per cent of cases.
A high BMI and insufficient physical activity cause common cancers specific to women, such as breast and corpus uteri, the researchers said.
They added that a rising prevalence of high BMI, lack of physical activity and an increasing access to and intake of unhealthy, unbalanced diets — particularly in middle and lower-income countries — could further increase the future burden of cancer linked to high BMI.
“For men, many causes of cancer can be linked to behavioural risk factors. Smoking remained the single largest contributor to the cancer burden, causing not only nearly 60 per cent of all new lung cancer cases in men but also 15 other cancer types,” the authors said.
The team noted a “clear persistence of infectious causes of cancer in sub-Saharan Africa and South Asia (which) further emphasise the importance of infection control on long-term cancer control.”
The findings also highlighted potential opportunities for cancer prevention, including tobacco control, preventing infections, and nationally adapted strategies suited to each region, the authors said.
They also pointed to how data quality and availability can vary widely across regions, with particularly large gaps in low and middle-income countries where cancer and risk factor data are often limited.
A better surveillance and more detailed data would help strengthen future estimates and improve policy guidance, they said.>
