Radiographic progression of asbestosis: preliminary report.

In a collaborative study with the Pneumoconiosis Medical Panel, 232 asbestos workers were seen between 1967 and 1975. During this time, 50 of the 232 (21.5%) workers dies, 33 (13.8%) from respiratory disease probably related to asbestos exposure [10 (4.3%) pleural mesothelioma, three (1.3%) peritoneal mesothelioma, 10 (4.3%) asbestosis, 10 (4.3%) carcinoma of the lung]. Of the 182 survirors, 119 were recalled for other studies, and follow-up data were obtained as additional information at the same time, over a 1--7 year period. Paired radiographs were read, and 21 patients (17.6%) had worsened. As expected, the frequency of progression increased with a longer follow-up time, so that about one third of the subjects displayed progression after a minimum follow-up of 6 years. Ten of 73 patients (13.6%) had progressed in 3 years or less and may be defined as rapid progressors. No particular clinical feature distinguished clearly between progressors and nonprogressors, but there was a trend toward a greater frequency and higher titer of ANA among the progressors in this group. There was also a higher frequency of progression in those who were initially classified radiographically as 1/1 of 1/2 than in those with other initial radiographic appearances. This pilot study is now forming the basis for a larger, longer-term comprehensive survey.