ASBESTOS EXPOSURE ACCORDING TO DIFFERENT EXPOSURE INDEXES AMONG FINNISH LUNG-CANCER PATIENTS

During a 6-month period all lung cancer patients in a university hospi tal chest clinic were investigated for asbestos exposure by means of p ersonal interview, bronchoalveolar lavage (BAL), roentgenograms, lung function testing, histology and measurement of fibre concentrations in lung tissue samples using scanning electron microscopy (SEM). About o ne-third of the patients (33%) were classified as having been exposed to asbestos on the basis of the interview. BAL was performed and AB co unts were done in 51 patients. Fourteen (27%) BAL specimens had AB cou nts of 1 or more AB/ml, which is the conventional limit for non-trivia l asbestos exposure. For a subgroup of 25 operated lung cancer patient s fibre analysis was also available. In six cases (30%) the asbestos-c ontaining samples had asbestos fibre concentrations equal to or more t han 1 million fibres/g dry lung. In eight (32%) of the operated lung c ancer patients histopathologically confirmed fibrosis was seen; five o f these patients were in the two highest exposure classes. Pleural pla ques on X-ray films were seen in six (24%) of the operated cases. With each indicator of exposure about 30% of lung cancer patients were fou nd to have been exposed, confirming the ''one-third rule''; however, w hen all the information was collated there were three cases (12%) in w hich exposure was most obvious according to the different parameters u sed in this study. In these three cases the cancer could well be attri buted to asbestos. Anthophyllite was present in all asbestos-containin g samples and anthophyllite was the main fibre type in 61% of these sa mples.