Abstract
We have examined 32 cases of primary bronchogenic carcinoma which had been complicated with unilateral ventilatory impairment due to non-neoplastic pleuropul monary diseases.
The age-sex distributions revealed a much higher incidence among the aged males as compared with the incidence of the lung cancer in general population. The time intervals between the past non-neoplastic lung disease and the detection of the lung carcinoma were over 10 years in 75 % of cases in this series. In 27 cases (84.4%), carcinoma developed in the healthy side of the lung.
Analyses as to the histological types of the tumors disclosed:
1) the frequency of the squamous cell carcinoma was high (17 cases, 53.1%), 2) all of 17 squamous cell carcinomas and 2 undifferentiated small cell carcinomas developed in the healthy side of the lung, and 4 of 9 adenocarcinomas in the lung with ventilatory impairment.
From the results obtained, it is considered that the bronchial epithelium of the healthy side of the lung was exposed more to the exogeneous carcinogens than that of the diseased side because of the increased ventilatory volume in that side, resulting in the higher risk of the development of squamous cell carcinoma.
