The incidence of non-small cell lung cancer (NSCLC) in never-smokers appears to be increasing independent of sex, stage, and race/ethnicity, according to a study published in the Journal of the National Cancer Institute.1
Approximately 10% to 15% of lung cancer cases in the United States occur in people who have never smoked tobacco; however, whether this rate is increasing is unclear. To examine whether the proportion of never-smokers developing lung cancer is increasing, researchers retrospectively analyzed data from 10,593 NSCLC cases and 1510 small cell lung cancer (SCLC) cases.
The investigators collected demographic information obtained from 1990 to 2013 from the registries of 3 diverse institutions: The University of Texas Southwestern Medical Center in Dallas, Parkland Hospital in Dallas, and Vanderbilt University Medical Center in Nashville, Tennessee.
Results showed that the proportion of never-smokers who developed NSCLC increase from 8.0% during the period between 1990 and 1995 to 14.9% in 2011 to 2013 (P <.001). The investigators observed similar results after controlling for sex, stage at diagnosis, and race/ethnicity.
However, researchers found no statistically significant increase in the cases of SCLC (1.5% in 1990 to 1995 to 2.5% in 2011 to 2013; P =.36) or squamous cell NSCLC among never-smokers from the 1990 to 1995 period to the 2011 to 2013 period.
Given the findings that show that the number of NSCLC cases increased in never-smokers irrespective of sex, stage, and race/ethnicity, the authors conclude that the actual incidence of lung cancer in people who have smoked is increasing.
1. Pelosof L, Ahn C, Gao A, et al. Proportion of never-smoker non–small cell lung cancer patients at three diverse institutions. J Natl Cancer Inst. 2017 Jan 27. doi: 10.1093/jnci/djw295 [Epub ahead of print]