Purpose: Lifetime and age-conditional probability (risk) estimates of developing lung cancer in the United States are presented by age, race, and gender. Effects on the risk estimates of an aging population and changing tobacco use are identified.
Methods: Risk estimates were derived by applying cross-sectional, population-based incidence rates of malignant lung cancer and mortality rates from other causes to a hypothetical cohort. The cohort was aged through a double-decrement life table to determine the expected proportion of the population that would develop the disease across age intervals. Incidence and mortality data were obtained from the Surveillance, Epidemiology, and End Results (SEER) Program and the National Centers for Health Statistics, respectively.
Results: Among all cancers, risk estimates of developing lung cancer within 10 years, conditioned on being free of the disease at age 50, 60, or 70, ranked second to prostate cancer for men and second to breast cancer for women. For men, despite higher incidence rates of lung cancer for blacks than whites across most age groups, the risk of developing this disease over the life-span becomes similar, because white men are more likely to live to older ages where lung cancer is common. For women, lung cancer incidence rates are similar between Whites and Blacks, but an older age distribution among white women explains their greater lifetime risk of being diagnosed with the disease. Changes in the age distribution between the mid 1970s and the mid 1990s had little impact on the short-term risk estimates of developing lung cancer for younger ages but had a large influence on long-term risk estimates, particularly for the older age groups.
Conclusions: Declining lung cancer among younger age groups may be attributed to declining tobacco use among the cohorts, but several more years may be required before the trends begin to fall in older age groups, particularly in women. In the meantime, an aging population is contributing to more people being diagnosed with lung cancer. Consequently, the projected risk of developing lung cancer will remain high for several years to come.