Giving up smoking may have benefits even to those with the most advanced stages of cancer, new research suggests.
Published in the Journal of the National Comprehensive Cancer Network, the study found that people with cancer who quit smoking had a 97 per cent lower risk of dying within two years compared to those who kept smoking.
Scientists have said their new study shows it is “never too late” to cut the habit, which is linked to around 80,000 deaths a year in the UK.
Researchers followed more than 13,000 individuals with cancer, tracking whether they quit smoking in the first six months after being seen by doctors. They found that those who continued to smoke had a substantially higher risk of death within two years compared to those who quit smoking.
This survival benefit was seen across all cancer types and stages, the study found, including the most serious stages where treatments are less likely to cure tumours.
But despite these benefits, only about one in five smokers quit within six months of their visit.
Lung cancer is one of the most common and serious types of cancer, with more than 43,000 people diagnosed in the UK each year, according to the NHS. Although people who have never smoked can develop lung cancer, smoking is the most common cause - accounting for more than 70 out of 100 cases - due to the toxic substances inhaled while smoking.
The NHS has led a number of initiatives to encourage people to stop the habit, including Stoptober, an annual campaign in England that encourages smokers to quit for the month of October.
But data from April of this year shows smoking rates may be on the rise in some parts of England, despite efforts to slash numbers.
In 2023, the UK government rolled out a targeted lung cancer screening programme with the aim of detecting cancer sooner and speeding up diagnosis.
Lead author of the study Dr Steven Tohmasi said the research showed how lifestyle changes, such as quitting smoking, can “prolong survival even more than some chemotherapies”.
“Our research reinforces the idea that smoking cessation should be considered the fourth pillar of cancer care — alongside surgery, radiation therapy, and chemo or immunotherapy,” he continued.
“Future cancer care must treat smoking cessation not as an optional extra, but as a core part of the treatment plan. By doing so, we can maximise survival, improve quality of life, and truly deliver comprehensive oncology care.”
“It is never too late, and no one is ever ‘too sick’ to quit smoking,” added senior author Dr Li-Shiun Chen. “Our study found that individuals with cancer who stop smoking after their diagnosis live significantly longer than those who continue smoking, even when their cancer is at an advanced stage.
“This data argues for an important paradigm shift to routinely include tobacco treatment as part of care in order to extend survival and improve outcomes for all people with cancer.”
Megan Winter, Health Information Manager at Cancer Research UK, said: “Tobacco remains the biggest cause of death in the UK, responsible for around 160 cancer cases every day. Stopping smoking completely is the best thing you can do for your health, and studies like this show that it’s never too late to stop.
“We know that most people who smoke have tried to quit, but they need the right support to do so. That’s why the UK Government must deliver long-term funding for stop smoking support so everyone can access the tools they need to quit successfully. To help find what works, people can get free support from their local stop smoking service or talk to a pharmacist or GP.”
