Duration of smoking abstinence as a predictor for non-small-cell lung cancer survival in women.

BACKGROUND

Previous studies have attempted to investigate the impact of smoking cessation on lung cancer survival but have been limited by small numbers of former smokers and incomplete data.

METHODS

Over a six-year period, 5229 patients with non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC) were enrolled in a prospective cohort of whom 2052 were former smokers. Patient's characteristics were obtained from medical records and a baseline interview. Vital status was determined through multiple sources. Cox proportional hazards models were used to estimate the effect of smoking abstinence on post-diagnosis mortality.

RESULTS

For all patients with NSCLC, the median survival among never, former, and current smokers was 1.4 years, 1.3 years, and 1.1 years, respectively (P < 0.01). Female NSCLC patients had a significantly lower risk of mortality with a longer duration of smoking abstinence (RR per 10 years of smoking abstinence = 0.85; 95% CI: 0.75, 0.97). No effect of smoking abstinence on mortality was observed for women with SCLC or for men with either histologic group.

CONCLUSIONS

The identification of smoking history as a prognostic factor in lung cancer survival supports previous research suggesting a direct biologic effect of smoking on survival. However, this effect may vary by sex and type of lung cancer.