Quitting smoking early is linked to improved survival rates for people diagnosed with lung cancer, research suggests.
The findings indicate that the benefits of giving up smoking before being being diagnosed continue to be seen even after a diagnosis.
A study found that among those diagnosed with the most common form of lung cancer: non-small cell lung cancer (NSCLC); current smokers had a 68% higher death rate and former smokers had 26% higher death rate compared to people who had never smoked.
According to the findings, the longer a patient had gone without smoking before being diagnosed, the better their odds of survival were.
This wide range gave us confidence in our results - that the benefit of pre-diagnosis smoking cessation persists even after lung cancer is diagnosed— Professor David Christiani, Harvard University
The study is one of the few to examine death rates not just among current and never smokers, but also among former smokers, enabling more robust findings about the impacts of giving up the habit, researchers said.
Never smoking was associated with the best chance of surviving after a lung cancer diagnosis, but the findings showed significant links between lower death rates and having quit smoking pre-diagnosis.
The longer a patient went without smoking, the more health benefits they had, the researchers found.
For former smokers, doubling the years of smoking cessation before their lung cancer diagnosis was significantly associated with prolonged survival, the researchers say.
But doubling smoking-pack years was associated with shorter survival among current and former smokers.
Senior author David Christiani, the Elkan Blout Professor of Environmental Genetics, at Harvard University, said: “Our participants’ smoking histories varied, with some having stopped smoking a few years before their diagnosis and others having stopped several decades before.
“This wide range gave us confidence in our results – that the benefit of pre-diagnosis smoking cessation persists even after lung cancer is diagnosed.”
The study, published in the Jama Network Open journal, followed 5,594 people with NSCLC enrolled in the Boston Lung Cancer Survival Cohort at Massachusetts General Hospital between 1992 and 2022.
Of this group, 795 had never smoked, 3,308 were former smokers, and 1,491 were current smokers.
People were asked to complete questionnaires about their smoking habits and other health and demographic information, with the researchers checking in on their survival every 12 to 18 months.
During the study period, 3,842 of the people enrolled died – 79.3% of the current smokers, 66.8% of the former smokers, and 59.6% of the never smokers.
The researchers noted that associations between survival and smoking history may vary depending on the stage the lung cancer was diagnosed at, and that the study did not account for the different kinds of treatment participants.
Hazel Cheeseman, deputy chief executive of Action on Smoking and Health (ASH), said: “Most people find a lung cancer diagnosis terrifying.
“Too often, smokers think the damage is done and there is no point in stopping but quitting gives them the best chances of survival.
“Our healthcare services must reflect this too.
“Too few smokers receive proper support to stop as part of the NHS’s existing lung health check schemes despite evidence that it can double their chances of successfully stopping – this must change in the future.”
