CHANGING TRENDS IN HISTOLOGIC TYPES OF LUNG-CANCER DURING THE LAST DECADE (1981-1990) IN KOREA - A HOSPITAL-BASED STUDY

A review of the histopathology and past history of 2229 patients with primary lung cancer diagnosed at the Yonsei UniversitY Medical Center from 1981 to 1990 was,performed to investigate the changes in histolog ic types and the relationship to smoking history. The most frequent hi stologic type of lung cancer was squamous cell carcinoma (956 patients , 54-0%) followed by adenocarcinoma (311 patients, 17.6%) in males (17 72 patients), and adenocarcinoma (206 patients, 45.1%) followed by squ amous cell carcinoma (126 patients, 27.6%) in females (457 patients). In both sexes, the predominant type was adenocarcinoma under the age o f 40, whereas squamous cell carcinoma was the most frequent type above the age of 40. While squamous cell carcinoma decreased over 10 years (54.3% in 1981, 44.3% in 1990), adenocarcinoma showed a gradually incr eased incidence (17.0% in 1981, 28.3% in 1990) in both sexes, and the proportion of small cell carcinoma and large cell carcinoma remained u nchanged. These changes in histologic type were more prominent in non- smokers. In conclusion, the increasing incidence of adenocarcinoma in both sexes, especially in non-smokers, suggests the possible presence of etiologic factors other than smoking, such as environmental polluti on.