CIGARETTE-SMOKING AND CHANGES IN THE HISTOPATHOLOGY OF LUNG-CANCER

Background: Adenocarcinoma of the lung, once considered minimally rela ted to cigarette smoking, has become the most common type of lung canc er in the United States, The increased incidence of this cancer might be explained by advances in diagnostic technology (i.e., increased abi lity to perform biopsies on tumors in smaller, more distal airways), c hanges in cigarette design (e.g., the adoption of filtertips), or chan ges in smoking practices, We examined data from the Connecticut Tumor Registry and two American Cancer Society studies to explore these poss ibilities, Methods: Connecticut Tumor Registry data from 1959 through 1991 were analyzed to determine whether the increase in lung adenocarc inoma observed during that period could be best described by birth coh ort effects (i.e., generational changes in cigarette smoking) or calen dar period effects (i.e., diagnostic advances), Associations between c igarette smoking and death from specific types of lung cancer during t he first 2 years of follow-up in Cancer Prevention Study I (CPS-I), in itiated in 1959) and Cancer Prevention Study II (CPS-II, initiated in 1982) were also examined, Results: Adenocarcinoma incidence in Connect icut increased nearly 17-fold in women and nearly 10-fold in men from 1959 through 1991, The increases followed a clear birth cohort pattern , paralleling gender and generational changes in smoking more than dia gnostic advances, Cigarette smoking became more strongly associated wi th death from lung adenocarcinoma in CPS-II compared with CPS-I, with relative risks of 19.0 (95% confidence interval [CI] = 8.3-47.7) for m en and 8.1 (95% CI = 4.5-14.6) for women in CPS-II and 4.6 (95% CI 1.7 -12.6) for men and 1.5 (0.3-7.7) for women in CPS-I, Conclusions: The increase in lung adenocarcinoma since the 1950s is more consistent wit h changes in smoking behavior and cigarette design than with diagnosti c advances.