
The number of lung cancer diagnoses amongst people who have never smoked is increasing globally, says the World Health Organization’s (WHO) cancer agency.
According to a new study published in The Lancet Respiratory Medicine journal, air pollution is said to be an ‘important factor’ in this rise.
The International Agency for Research on Cancer (IARC) estimates that lung cancer cases in those who have never smoked cigarettes or tobacco is the fifth highest cause of cancer deaths in the world.
The study, conducted by IARC researchers, sought to estimate national-level lung cancer cases for four different subtypes: adenocarcinoma, squamous cell carcinoma, small- and large-cell carcinoma.
The researchers found that adenocarcinoma, which starts in glands that produce mucus and digestive fluids, has become the most dominant of the four subtypes among both men and women. They also found that, in 2022, the subtype accounted for 53-70% of lung cancer cases in people who have never smoked before.
Adenocarcinoma is ‘weakly related’ with cigarette smoking, according to the researchers.
The study also found that 15% (around 200,000) of all adenocarcinoma cases in 2022 were a result of air pollution. The researchers believe this suggests that number of lung cancer cases linked to air pollution is on the rise, especially in east Asia and China.
‘Urgent monitoring’ needed
Dr Freddie Bray is the study’s lead author and head of the IARC cancer surveillance branch. He believes these findings underscore the need for ‘urgent monitoring of the changing risk of lung cancer’.
He told The Guardian: ‘With declines in smoking prevalence – as seen in the UK and US – the proportion of lung cancers diagnosed among those who have never smoked tends to increase.
‘Whether the global proportion of adenocarcinomas attributable to ambient air pollution will increase depends on the relative success of future strategies to curtail tobacco use and air pollution worldwide.’
He also said: ‘Changes in smoking patterns and exposure to air pollution are among the main determinants of the changing risk profile of lung cancer incidence by subtype that we see today.
‘The diverging trends by sex in recent generations offer insights to cancer prevention specialists and policy-makers seeking to develop, and implement tobacco and air pollution control strategies tailored to high-risk populations.’
Cancer treatment delays
This comes as new data shows that more than 500,000 UK cancer patients waited at least two months for treatment.
Experts have warned that ‘delays will cost thousands of lives’.
In the decade up to November 2024, NHS data shows that 506,335 cancer patients did not begin treatment within the 62-day government target. This means less than seven in 10 patients (69%) were seen within two months.
According to Cancer Research UK, there are nearly 50,000 new lung cancer cases diagnosed each year, making it the third most common form of cancer in the UK.
The charity says it is also the leading cause of cancer death in men and women, with lung cancer survival not seeing much improvement over the last 50 years. Less than one in 10 (9.5%) are said to survive the disease for 10 years or more, according to Cancer Research UK.
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