THE INCREASING INCIDENCE OF LUNG ADENOCARCINOMA - REALITY OR ARTIFACT- A REVIEW OF THE EPIDEMIOLOGY OF LUNG ADENOCARCINOMA

Lung adenocarcinoma is the most common cell type in females (smokers o r non-smokers) and in non-smoking males. Its incidence has been increa sing in younger cohorts of males and females until very recent years. Changes in classification and in pathological techniques account for s ome of this increase. In females and non-smoker males, the increase co uld be partly due to a detection bias in former studies. Nevertheless, successive cohorts over time seem more likely to develop adenocarcino ma and less likely to develop squamous cell carcinoma. These differenc es between birth cohorts suggest that the increasing incidence of aden ocarcinoma is not only due to changes in pathological diagnosis. Geogr aphical differences are also observed: in Europe, the squamous cell ty pe still predominates and an increase in incidence of adenocarcinoma h as only been reported in the Netherlands. In Asia, in the 1960s and 19 70s, the proportion of adenocarcinoma was higher than in North America or Europe and seems to be increasing, To what extent these difference s are due to differences in establishing diagnosis remains unknown, De spite these biases in temporal and geographical trends detailed in thi s review, there has probably been a true increase in incidence of aden ocarcinoma. An explanation for this should be sought in studies on det ailed smoking history and passive smoking exposure, occupational expos ure, diet and cooking, pollution and other environmental factors.