Global Patterns and Trends in Lung Cancer Incidence: A Population-Based Study.

Introduction: Lung cancer (LC) has been the most common cancer worldwide for several decades. This study comprehensively examines recent geographic patterns and temporal trends in LC incidence from 1978 to 2012 in 43 countries and evaluates the effects of birth cohort and period on temporal trends.

Methods: Data were retrieved from the Cancer Incidence in Five Continents database. Joinpoint regression and age-period-cohort models were applied.

Results: The age-standardized rate was highest in Turkey (69.3 per 100,000 person-years) for men and in Denmark (36.7) for women in the period 2008 to 2012. Sex disparities were noted in most countries. From 1978 to 2012, a total of 19 countries had significantly declining trends among men, whereas 26 countries had significantly increasing trends among women (all p < 0.05). Quasi-reversed V-shaped and U-shaped incidence rate ratio trends indicating birth cohort effects were detected in 26 countries for men, with the highest risks mainly occurring in the 1930 to 1950 birth cohorts. However, the risks among recent generations have moderately increased in the People's Republic of China and Japan for men and sharply increased in Lithuania, Belarus, and Republic of Korea for women. Incidence rate ratio increases were steep among earlier birth cohorts and gradual among the post-1930s cohorts in 15 countries for women. Period effects were more evident than birth cohort effects in five countries for both sexes.

Conclusions: Disparities in LC incidence and carcinogenic risk persist worldwide. Our findings identified high-risk target populations for primary prevention to reduce the LC incidence and highlighted the urgent need for etiologic studies to identify the reasons for pronounced cohort-specific risk increases in certain countries.