A Decade of Never-smokers Among Lung Cancer Patients-Increasing Trend and Improved Survival

It is not known whether clinicopathologic characteristics, treatment, and survival of never-smokers among lung cancer incident cases have changed over time. We assessed the trend and overall survival (OS) of these patients within our institution during a 10-year period.

We reviewed 2 cohorts of non-small-cell lung cancer patients with a diagnosis from 1999 to 2002 and from 2008 to 2011. The patient characteristics and OS were compared by smoking status within each cohort and between the 2 cohorts over time.

Of the 992 patients in the 1999-2002 cohort and the 1318 patients in the 2008-2011 cohort, 902 and 1272 had a known smoking status, respectively. The proportion of never-smokers increased from 31% in 1999-2002 to 48% in 2008-2011 (P < .001). Within both cohorts, the differences in characteristics among never-, former-, and current-smokers have remained largely constant over time. A greater proportion of never-smokers had Eastern Cooperative Oncology Group performance status 0 to 1 and adenocarcinoma. The median OS increased from 15.5 months in 1999-2002 to 24.9 months in 2008-2011 (P = .001) for never-smokers, 12.3 to 15.9 months (P = .150) for former-smokers, and 10.5 to 13.9 months (P = .011) for current-smokers. The larger survival improvement among never-smokers was likely accounted for by the larger increase in never-smokers who were treated with tyrosine kinase inhibitors and pemetrexed over time.

We found an increasing trend of never-smokers among incident lung cancer cases and improved survival for these patients during a 10-year period. The documentation of smoking status in any national cancer registry is vital to estimate the true incidence of lung cancer among never-smokers over time.