OBJECTIVES: Smoking is a modifiable risk factors for lung resections but to what extent preoperative smoking cessation reduces that risk remains unclear. The study hypothesis was that potential benefit of smoking cessation can be assessed measuring the risk difference between active and former smokers in a large cohort of patients. METHODS: Data were extracted from the French Society of Thoracic and Cardiovascular Surgeons (SFCTCV) database. The study cohort was composed of patients who underwent lung resection for cancer from January 2002 to December 2020 and for which information on smoking status was available. The risk of overall and specific postoperative complications according to smoking status was defined by logistic regression models and results were presented in terms of OR and relative 95% confidence intervals adjusted for confounding factors. RESULTS: Out of the 7204 analysed patients, at the time of surgery, 20.2% were active smokers, 60.7% ex-smokers and 19.1% never smokers. As compared to former smokers, active smokers experienced a higher rate of respiratory complications (OR 1.5, CI 1.2-1.7) and infections (OR 1.6, CI 1.3-1.9). Postoperative atelectasis was significantly reduced in former smoker (3%) as compared to active smokers (6.9%, p <
0.01). In active smokers, the risk was related to the level of exposure, being higher for smokers of more than 40 P/Y. CONCLUSIONS: After lung surgery, active smokers experience an higher risk of respiratory complications, infections and prolonged air leak as compared to former smokers. This risk seems to be related to the level of exposure.