UICC/Cincinnati Classification of the Radiographic Appearances of Pneumoconioses: A Cooperative Study by the UICC Committee

Abstract

The International Union Against Cancer (UICC) convened a Working Group on Asbestos and Cancer in 1984 which recommended that an international classification of the radiographic appearances of the chest films of asbestos-exposed workers be developed. Three interested groups-the UICC Working Party, the U.S. Public Health Service Group of Radiologists, and a McGill University epidemiologic research group-met in Cincinnati in November. 1967. Agreement was achieved on a proposed new classification which is an extension of the International Labour Organization (ILO) 1958 scheme. Tests of the practicability and intra- and inter-observer variations made subsequently were sufficiently encouraging for the Group to recommend publication of the scheme at their next meeting ill April 1968. The principal extensions from the ILO 1958 scheme are: 1. Small opacities are subdivided into “rounded” (as in the ILO 1958 scheme) and “irregular.” This new “irregular” group has four categories, 0-3, and describes verbally and with standard films the linear or irregular small opacities which are frequentlyseen in asbestosis and in some of the other pneumoconioses. 2. Large opacities, defined as in the ILO 1958 scheme, carry an extra comment on whether the outline of the shadow is well or ill-defined. 3. Pleural thickening, for which a single symbol was used in the ILO 1958 scheme, is brought into the main classification and divided into “calcified” and “noncalcified.” A system of grading, with standard films, is provided. Costopbrenic angle obliteration is separately recorded. 4. Ill-defined cardiac outline (shaggy heart) and diaphragmatic outline are also separately classified, using standard films. 5. The additional symbols used in the ILO scheme are divided into an ohligatorv and an optional group. With a well-designed reading sheet, the classification was found easy to use by six readers from four countries in 16,000 radiographs from a survey of asbestos miners and mill workers in Quebec. The variation within the same observers was tested and found to he reasonably small. The variation between observers was tested in a study of 100 radiographs read by 12 readers from six countries. The results indicate that the classification should be satisfactory for many epidemiologic purposes. But it is clear that further improvement in definitions and in the standard films might be expected to improve the agreement between readers. The classification is known as the UICC/Cincinnati Classification of the Radiographic Appearances of Pneumoconioses. We believe it can be used to describe all the principal types of pneumoconiosis.