TUMORS IN ICELAND .7. MALIGNANT EPITHELIAL TUMORS OF THE LUNG - A HISTOLOGICAL CLASSIFICATION, EPIDEMIOLOGICAL CONSIDERATIONS AND RELATION TO SMOKING

Abstract

All malignant epithelial tumors of the lung submitted for a histological diagnosis in Iceland between 1955-1974 and available for review were typed histologically according to the WHO Classification originally published in 1967 and later revised and republished in 1981. The series includes 355 tumors, 217 from males and 138 from females, and 78% of all registered malignant tumors of the lung. Among males the incidence of squamous cell carcinoma and small cell carcinoma was about equal and adenocarcinoma was in 3rd place. Among females the incidence of adenocarcinoma was the highest and that of small cell carcinoma in 2nd place, other types being much less frequent. During the period there was a rise in the incidence of all the major histological types in both sexes and the greatest rise was in adenocarcinoma, where the incidence doubled in males and tripled in females. Among European nations the incidence of lung carcinoma is the lowest for Icelandic males and the highest for Icelandic females. There is a close correlation between the sale of cigarettes and the incidence of lung carcinoma in Iceland. Among those lung carcinoma patients with known smoking histories, all with small cell carcinoma, almost all with squamous cell carcinoma and 4 of 5 with adenocarcinoma were smokers.