Lung cancer is the leading cause of cancer death in France; smoking is the main cause. However, a minority of smokers develop the disease. How is it possible ? What protects them?
A minority of smokers with lung cancer
Tobacco is the main responsible for the majority of lung cancers at 90%. However, many smokers escape this cancer. Indeed, of the 13 million smokers in France, 46,000 develop cancer lung every year. According to researchers at the Albert Einstein College of Medicine in New York, some smokers have robust mechanisms that limit lung cell mutations. A mechanism that would protect them from lung cancer.
We count in pack-years of smoking
The results of the American scientists were published on April 11 in Nature Genetics . They analyzed data from people aged 11 to 86 who had smoked, compared with those who had not smoked. The researchers counted in each year. A year-pack of smoking corresponds to a pack of cigarettes smoked per day for a year.
Cell mutations in smokers
The researchers found that the mutations were accumulating in lung cells non-smokers as they grew older. Mutations that are much more numerous in smokers. Thus, the study confirms that smoking “increases the risk of lung cancer by increasing the frequency of mutations”.
Mutations stop after 23 packet-years
The number of cellular mutations increases with the number of pack-years of smoking…stopping increasing after 23 pack-years of exposure. In short: the heaviest smokers are not necessarily the most exposed to the risk of lung cancer.
“This mutation leveling could come from the fact that these people have very efficient systems to repair DNA damage or to detoxify cigarette smoke,” the researchers assume.