Abstract
To examine the risk of chromate in relation to lung cancer, we carried out a prospective study on 84 male workers who had worked at a chromate processing. factory. Cytological examinations of sputum were repeatedly performed during the period from Oct., 1975 to Oct., 1981. Bronchoscopy was performed for cases with atypical squamous metaplasia or malignant cells. As a result, 6 cases with lung cancer were found, 2 of which were double primary lung cancer cases.
The mean age of these 6 cases was 66 at the time of diagnosis and the mean duration of exposure to chromate was 21 years and 8 months. Five of the lesions weresquamous cell carcinoma and 2 were small cell carcinoma. Five lesions were able to find by bronchoscopy, and 5 were diagnosed as early cancer or almost early cancer.
The morbidity of lung cancer in this group was estimated to be as high as 1, 190 per 100, 000 population. Morbidity rate of this group was 16.6 times higher than that of general population after ajusting for age and sex, and it was 21.6 times higher in workers who worked more than 9 years at a chromate factory.
These results emphasize the usefulness of cytological examination and bronchoscopy for detection of such an occupational lung cancer and demonstrate that chromate is a high risk factor for lung cancer.
