Quitting smoking at any age helps reduce the risk of cancer, according to a large study, which found that the biggest drop in cancer risk came after the first decade of quitting.
The chances of developing cancer halved in people who stopped smoking for at least 15 years, compared with those who continued to smoke, with the risk of lung cancer falling further and faster, especially in those who quit before middle age.
Researchers analyzed medical data from nearly 3 million Koreans who had health examinations from 2002 and recorded cases of cancer, including lung, liver, stomach and colorectal tumors until 2019. Over the course of the study, nearly 200,000 participants ‘ received a cancer diagnosis.
“Regardless of age, quitting smoking has been shown to reduce the risk of developing cancer, particularly lung cancer, with early cessation before middle age leading to significant reductions,” said Dr. Jin-Kyoung OWHO led the study at the National Cancer Center near Seoul.
After an average follow-up of 13 years and five months, the risk of lung cancer among those who quit fell by 42%, with smaller decreases of 27%, 20% and 14% recorded for liver, colorectal and stomach cancer respectively is, compared to those who continue to smoke. Details are published in Jama network open.
Cancer causes more than a quarter of all deaths in the UK each year, with lung cancer by far the most common. Smoke causes at least 15 different cancers, affecting the lungs, bladder, stomach and intestines and organs such as the kidneys and liver. Tobacco is the leading preventable cause of cancer and death in the country.
According to the study, smokers who quit before the age of 50 had a 57% reduction in lung cancer risk over the follow-up period compared to those who continued to puff. Those who quit at 50 or older experienced a 40% reduction in lung cancer risk over that time.
“Quitting smoking, regardless of your age, can have significant health benefits,” Dr Oh told the Guardian. “Individuals who stopped smoking after middle age had a 40% lower risk of developing lung cancer compared to those who continued to smoke. Don’t think it’s too late. We encourage you to consider starting your journey to quit smoking.”
The development of cancer is a multi-stage process, with DNA mutations piling up until one or more cells are damaged in a way that causes them to replicate uncontrollably, said Robert West, emeritus professor of health psychology at University College London and an expert on addiction. The further along that path the smoker is when they quit, the more likely they are to eventually develop cancer.
“This study confirms two important facts,” West said. “One is that it can take many years for the risk of cancer to decrease compared to continuing to smoke. The other is that the decline is greater for those who quit at a younger age.”
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“For smokers, it shows how important it is to stop smoking as young as possible. There is a benefit at every age, but the younger smokers can quit, the more of their lives they get back,” Prof West added. “The way out of smoking is clear: try to quit at least once a year and use evidence-based specialist quit-smoking support with each quit attempt rather than trying to go cold turkey.”
Malcolm Clarksenior prevention policy manager at Cancer Research UK, said: “Smoking remains the leading cause of cancer, causing around 150 cases every day across the UK – and the majority of people who smoke have tried to quit.
“It’s never too late to quit smoking, but people need support to help them quit. This is why we support the UK Government’s increased funding for stop-smoking services and the upcoming legislation to change the age of sale of tobacco. If implemented, it could help prevent the next generation from ever becoming addicted to tobacco.”
