Lung cancer is the leading cause of cancer death in Australia and worldwide.
A large collaborative study led by UNSW’s Centre for Big Data Research in Health pooled seven Australian cohort studies of 370,000 people. The project found that tobacco smoking continued to be responsible for most of the lung cancer burden in Australia.
Senior Research Fellow Dr Maarit Laaksonen said: “More than three out of four lung cancers are caused by ever smoking.
“Current smoking is responsible for more than half of lung cancers and past smoking for nearly a quarter.”
The study showed that the lung cancer risk remained elevated for 40 years after stopping smoking, with the risk approximately halving every 10 years. Of the 74,600 lung cancers attributable to current smoking in Australia in the next 10 years, 25,400 could be avoided if all current smokers were to quit.
The findings show harm from smoking persists for decades and emphasise the importance of plain packaging and other tobacco control activities that discourage smoking uptake.
While most current smokers do not describe themselves as ‘heavy’ smokers, those who smoke fewer than 20 cigarettes a day carry a large proportion of the future lung cancer burden.
The researchers also found that eating two serves (about 300 grams) of fruit each day may reduce the lung cancer burden by 8%, and doing the recommended 150 minutes of moderate or 75 minutes of vigorous physical activity each week may reduce the lung cancer burden by 16%.
Currently, about 16% of Australians smoke but roughly half of all Australians are not meeting the guidelines for fruit intake and 74% are not meeting guidelines for physical activity.
“The majority of Australians could benefit from increasing their fruit intake and physical activity. But for those who currently smoke, stopping smoking should be the first course of action,” Dr Laaksonen said.
Overall, at least four in five lung cancers appear preventable through behaviour modifications.
For the first time, the researchers were able to compare the lung cancer burden for different population subgroups. They found that men under the age of 75, unmarried, with lower educational levels, living in remote areas and not meeting the fruit consumption or physical activity recommendations, have the highest smoking-attributable lung cancer burden. Such high-burden groups are likely to benefit most from efforts that help them to not take up smoking, to quit smoking, and to be considered for screening to facilitate early detection.
“Our findings strongly support the dual importance of preventing the uptake of smoking and assisting quitting, in all Australians and especially in those with the highest burden,” Dr Laaksonen said.