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Lung Biopsy Study Finds It's Never Too Late To Quit Smoking


Rachael Funnell

Social Editor and Staff Writer

clockFeb 5 2020, 10:27 UTC
quit smoking better lung health

Quitting smoking can improve lung health at a molecular level, Leolintang/Shutterstock

It’s no great secret that giving up smoking is beneficial for your health, but a recent study published in the journal Nature has found that even heavy smokers have a shot at reducing their risk of lung cancer, provided they’re ready to give up completely. With around 1.1 billion smokers across the globe, according to the World Health Organization, the discovery offers an olive branch to smokers who think it’s too late to make a difference.

Smoking is directly linked to an estimated 1.8 million deaths from lung cancer annually, and in the UK accounts for 72 percent of reported cases of the disease. The increased risk of developing cancer arises from the way carcinogenic agents in cigarette smoke affect cells in the lungs. In a heavy smoker, many cells will carry a host of genetic mutations, some of which can be drivers for cancer. 


The study from the Wellcome Sanger Institute and University College London found that for participants who had once smoked regularly but since kicked the habit, the number of genetically healthy cells was hugely increased when compared to participants who were still smoking. This shows that there is still hope even for long-term smokers to turn around the health of their lung tissue and consequently reduce their future risk of lung cancer.

Using a sample comprised of smokers, ex-smokers, life-long non-smokers, and children, the study analyzed lung biopsies from 16 participants (an admittedly small sample size). Nine out of every 10 lung cells in those currently smoking were found to contain as many as 10,000 additional genetic mutations compared to non-smokers, each of which was directly linked to chemicals found in tobacco. Meanwhile, those who had given up smoking had four-times the number of genetically healthy cells lining their airways compared to those still smoking. 

The lungs of ex-smokers contained up to four times as many genetically healthy cells than those of current smokers. The Sanger Institute / UCL

“People who have smoked heavily for 30, 40 or more years often say to me that it’s too late to stop smoking – the damage is already done,” said senior author Dr Peter Campbell from the Wellcome Sanger Institute in a statement. “What is so exciting about our study is that it shows that it’s never too late to quit – some of the people in our study had smoked more than 15,000 packs of cigarettes over their life, but within a few years of quitting many of the cells lining their airways showed no evidence of damage from tobacco.” 


While the risk of chronic lung disease as a result of permanent damage deeper in the lung still remains, the capacity for an isolated minority of cells to repopulate the lung tissue with genetically healthy cells once smokers quit has raised promising questions as to whether there is a mechanism through which medicine can further promote the proliferation of these cells. Although further investigation is needed to fully understand the cell biology that underpins these findings, the study has shed light on how the cessation of smoking can improve lung health at a molecular level.

Thinking you'd like to kick the habit? These Ten Myths About Smoking might spur you on.

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