An autopsy study of lung cancer with special reference to the relationship between cigarette smoking and histological differentiation of adenocarcinoma and squamous cell carcinoma.

To clarify the relationship between cigarette smoking and the degree of differentiation of adenocarcinoma and squamous cell carcinoma of the lung, 207 male and 103 female cases of adenocarcinoma and 125 male and 26 female cases of squamous cell carcinoma, autopsied between 1958 and 1985, were reviewed. In males, adenocarcinoma cases increased as the degree of differentiation decreased. In females, poorly differentiated cases of adenocarcinoma and, in males, those of squamous cell carcinoma, were minimal, and the number of poorly-differentiated adenocarcinoma cases significantly less (p less than 0.005) in females than in males. The number of male smokers with adenocarcinoma increased, and that of female non-smokers decreased, as the degree of differentiation decreased. On the other hand, the number of male smokers with squamous cell carcinoma decreased and that of female non-smokers increased as the degree of differentiation decreased. The incidences of well-differentiated adenocarcinoma in female non-smokers, well-differentiated squamous cell carcinoma in male heavy smokers and poorly-differentiated squamous cell carcinoma in female non-smokers were prominent. A histopathological diagnoses of differentiated subtypes of adenocarcinoma and squamous cell carcinoma of the lung is useful and important in understanding the biological characteristics of lung cancer and also the effects of cigarette smoking.