Chronological observation of epidemiological characteristics of lung cancer in Taiwan with etiological consideration--a 30-year consecutive study.

In order to determine whether the epidemiological characteristics of lung cancer have changed within a certain period of time in Taiwan and to propose some causative factors for its rapid rate of increase we performed chronological and epidemiological studies based on the analysis of: (1) available vital statistics and demographic data for Taiwan after 1932; (2) data reported by WHO for international comparison; (3) prevalence surveys carried out in 1972-73 and 1977-78; and (4) 7,307 clinical cases collected from major hospitals since 1952. Some possible factors, i.e., the smoking history of patients, yearly tobacco consumption, geographical distribution of patients, and the number of motor vehicles were studied in correlation with epidemiological characteristics. We have found that the mortality of lung cancer in Taiwan has been increasing rapidly for both sexes. The rate of increase is probably the highest in the world. The prevalence rate increased from 15.26 per 100,000 population in 1972-73 to 22.35 in 1977-78. The male to female ratio has remained unchanged, roughly at 2:1, over the past 50 years. Adenocarcinoma contributed to about 60% of lung cancer in women and 35% in men. This proportion has not changed during the past 30 years. The cancer showed a striking urban predominance. The causes of the rapid increase in lung cancer in Taiwan cannot be explained solely by tobacco smoking, particularly for women, although it certainly plays an important role.