Twenty-year secular changes in sex specific lung cancer incidence rates in an urban Chinese population.

The objective of this study was to describe trends in the incidence rates of primary lung cancer in a geographically defined Chinese population. Primary lung cancer cases (N=40,022) diagnosed between 1981 and 2000 were identified by the Tianjin Cancer Registry. Age-specific and age-adjusted incidence rates to the world standard population were examined in both males and females. Age-period-cohort (APC) model and Poisson regression were used to assess the cohort effects and incidence trends. Crude and age-adjusted incidence rates in the study period were: 66.2/100,000 and 45.2/100,000 in males; and 47.7/100,000 and 28.2/100,000 in females, respectively. The major birth cohort effect can be described as for those born before 1940, in every age group lung cancer incidence rate increased as the birth years advanced. For those born after 1940, age specific incidence rates decreased as the birth years advanced. Results from the Poisson regression analyses suggested a statistically significant increasing trend of incidence rates of lung cancer from 1981 to 1990 and changed little afterwards. Through first 10 years of the study period between 1981 and 2000, lung cancer incidence rates increased in both males and females. While the study results suggest that the age-adjusted incidence rates may have reached their peak and may even decline, as the Chinese population ages, and smoking prevalence remains high, the number of new lung cancer cases will continue to increase and overall burden of lung cancer will remain high.