Centers for Disease Control and Prevention

Lung cancer is the leading cause of cancer death and the second most commonly diagnosed cancer (excluding skin cancer) among men and women in the United States (1,2). Although lung cancer can be caused by environmental expo-sures, most efforts to prevent lung cancer emphasize tobacco control because 80%–90 % of lung cancers are attributed to cigarette smoking and secondhand smoke (1). One sentinel health consequence of tobacco use is lung cancer (1,2), and one way to measure the impact of tobacco control is by examining trends in lung cancer incidence rates, particularly among younger adults (3). Changes in lung cancer rates among younger adults likely reflect recent changes in risk exposure (3). To assess lung cancer incidence and trends among men and women by age group, CDC used data from the National Program of Cancer Registries (NPCR) and the Nationa