Influence of smoking status on treatment outcomes after post-operative radiation therapy for non-small-cell lung cancer.

Background And Purpose: The role of post-operative radiotherapy in patients with resected non-small-cell lung cancer (NSCLC) is unclear. Modifiable factors, like smoking, may help guide therapy. We retrospectively evaluated the impact of smoking on control in patients undergoing post-operative radiation therapy (PORT) for NSCLC.

Materials And Methods: Between 1995 and 2007, 152 patients who underwent surgery for NSCLC were analyzed (median follow-up 26 months). Non-smokers were defined as patients who never smoked or who had stopped smoking at the time of initial consultation. Sixty seven percent were non-smokers; 5% never smoked, 40% of the non-smokers had ceased smoking for a year or less, while 55% had stopped for more than a year.

Results: On univariate analysis, smokers had worse 5-year local control than non-smokers (70% versus 90%, p=0.001) and locoregional control (52% versus 77%, p=0.002). The 5-year survival rate was 21% for smokers and 31% for non-smokers (p=0.2). On multivariate analysis, smokers maintained a detrimental effect on locoregional control (HR 3.6, p=0.0006).

Conclusions: Smokers at initial consultation have poorer local and locoregional control after PORT than non-smokers. In patients being considered for PORT for NSCLC, quitting smoking before treatment confers additional treatment advantage.