June 05, 2018

Lung Cancer Risk Drops Within 5 Years of Quitting Smoking

Smokers who quit have a substantially lower risk for lung cancer than current smokers even within 5 years of stopping smoking, new research shows.

“If you smoke, now is a great time to quit,” says lead author Hilary Tindle, MD, MPH, the William Anderson Spickard Jr. professor of medicine, Vanderbilt University School of Medicine in Nashville, Tennessee.

“The fact that lung cancer risk drops relatively quickly after quitting smoking, compared to continuing smoking, gives new motivation,” she said in a statement.

On the other hand, former heavy smokers still have over a threefold greater risk for lung cancer than those who never smoked for several decades after giving up the habit, the same research shows.

“Former heavy smokers need to realize that the risk of lung cancer remains elevated for decades after they smoke their last cigarette, underscoring the importance of lung cancer screening,” said senior author Matthew Freiberg, MD, professor of medicine, Vanderbilt Center for Clinical Cardiovascular Outcomes Research and Trials Evaluation, Nashville, Tennessee.

The study was published online May 16 in the Journal of the National Cancer Institute.

Data from the Framingham Heart Study (FHS) Original as well as the FHS Offspring cohort were analyzed for lifetime smoking and lung cancer incidence from 1954 to 1958 for the Original cohort and between 1971 and 1975 for the Offspring cohort. Lung cancer rates were tracked through 2013.

Information on smoking habits was collected and participants were categorized as current, former, or never smokers. Some 3905 participants from the FHS Original cohort and 5002 participants from the FHS Offspring cohort were included in the analysis.

“Most people (89.5%) who were smoking at baseline quit during follow-up and never relapsed,” the authors point out.

However, during a median follow-up of 25.1 years for the FHS Original cohort and 33.6 years for the FHS Offspring cohort, investigators documented 284 diagnoses of lung cancer.

“Among ever smokers, the majority of lung cancers (92.7%) occurred among heavy smokers, with 21.3 or more cumulative pack-years of smoking,” researchers note.

In this subgroup of participants with 21.3 or more cumulative pack-years of smoking, the unadjusted lung cancer risk was greater than 10-fold higher compared with those who had never smoked.

Are you running a solid smoking cessation program in your practice? It’s time to with MD Spiro.

Table. Incidence Rates of Lung Cancer.