[Silicosis and lung cancer].

A clinicopathological analysis was carried out on 50 cases of lung cancer with silicosis diagnosed from April 1975 to March 1988. All patients were males and the age distribution ranged from 47 to 85 years with a mean of 63.5 at diagnosis. They had been exposed to silica in tunneling for 3 to 42 years, with an average of 15.1. Forty eight cases smoked. Histologically, squamous cell carcinoma was the most common with 29 cases, followed by 10 small cell carcinomas, 6 adenocarcinomas, 4 large cell carcinomas and one adenosquamous carcinoma. Thirty seven tumors were located in peripheral regions, mostly upper lobe or S6, while 13 tumors were in large bronchi. As the most common histological types of lung cancer with silicosis were squamous cell carcinoma and small cell carcinoma, some carcinogens might be involved in tumorigenesis. Silica alone is not considered to be a carcinogen, however, silica containing adsorbed polycyclic aromatic hydrocarbons from cigarette smoking or from industrial pyrolysis can act as a carcinogen or promoter.