Background: Incidence rates for adenocarcinoma of the lung are increasing and are higher in the United States than in many other developed countries. We examine whether these trends may be associated with changes in cigarette design.
Methods: Lung cancer risk equations based on observations during 1960-1972 from the American Cancer Society Cancer Prevention Study I are applied to 5-year birth cohort-specific estimates of changes in smoking behaviors to predict birth cohort-specific rates of squamous cell carcinoma and adenocarcinoma of the lung among US White men for the period 1973-2000. These expected rates are compared to observed rates for the same birth cohorts of White men in the US Surveillance, Epidemiology and End Results (SEER) data.
Results: Changes in smoking behaviors over the past several decades adequately explain the changes in squamous cell carcinoma rates observed in the SEER data. However, predicted rates for adenocarcinoma do not match the observed SEER data without inclusion of a term increasing the risk for adenocarcinoma with the duration of smoking after 1965.
Conclusion: The risk of developing squamous cell carcinoma from smoking appears to have remained stable in the United States over the past several decades; however, the risk of adenocarcinoma has increased substantially in a pattern temporally associated with changes in cigarette design.