Study Reveals Duration of Smoking Cessation Affects Lung Cancer Screening Timing

Quitting smoking is indeed an important step to reduce the risk of lung cancer. However, a recent study shows that the length of time a person has stopped smoking should be taken into consideration when determining when lung cancer screening should be carried out.

The study was published in JAMA Network Open under the title “Risk-Adapted Lung Cancer Screening Starting Ages for Former Smokers”. The research was conducted by Clara Frick, Lára R. Hallsson, Uwe Siebert, Megha Bhardwaj, Ben Schöttker, and Hermann Brenner. The results were published on 23 December 2025 and are freely accessible via PubMed Central (PMC).

The researchers analysed data from 86,035 people with a history of heavy smoking, with at least 20 pack-years. Of that number, 2,109 people, or around 2.5 per cent, were diagnosed with lung cancer during the observation period.

The results showed a fairly clear pattern. The longer a person has stopped smoking, the lower the risk of lung cancer. People who had stopped smoking for more than 15 years had a much lower risk compared with those who still smoked.

These findings indicate that the time since a person stopped smoking is not merely a number, but can help illustrate a person’s level of lung cancer risk.

Currently, the U.S. Preventive Services Task Force (USPSTF) recommendations use age and smoking history criteria to determine which groups need to undergo lung cancer screening using low-dose computed tomography (LDCT).

The research by Frick and colleagues offers a more personalised approach. Based on their calculations, former heavy smokers who quit within the last five years could have a screening starting age of around 53 years. Meanwhile, those who have quit for more than 15 years could be in the range of 67 years, if the risk level of an active smoker at age 50 is used as a benchmark.

Although this study discusses screening strategies, the key message remains the same: quitting smoking provides significant health benefits.

The researchers consider that a risk-adapted screening approach can help determine who most needs screening and when screening should begin. This is important because LDCT can indeed help detect lung cancer earlier, but screening also has potential impacts such as false positive results and overdiagnosis.

Therefore, former smokers should not determine the need for screening based on age alone. Smoking history, level of tobacco exposure, duration of cessation, and health conditions need to be considered together by medical professionals.