Mineral fibre content of lung in mesothelial tumours: preliminary report.

A survey was made, through pathologists, of all 274 fatal cases of primary malignant mesothelioma in North America in 1972. For each case, a control with pulmonary metastases from a primary tumour other than lung cancer was matched for sex and age. Relatives and friends of both cases and controls were interviewed; and specimens of lung tissue were obtained for 100 case-control pairs and analysed 'blind' by electron microscopy and X-ray energy dispersion analysis. This report describes the preliminary results of the analyses of asbestos fibres in the first 37 case-control pairs: chrysotile fibres were far more prevalent than amphiboles, but equal quantities were found in cases and controls. There was, however, a clear excess of amosite fibres in male cases as compared with controls.