We describe here the results of the final 8 years of geographical and temporal data of a 33-year study of the
cancer experience of 12.8 million man-years of black miners working on the
gold fields of South Africa over the period 1964-96. These workers were recruited from 15 territories, the major areas during the most recent period being Lesotho (26.8%), Transkei (21.5%) and Mozambique (15%). The earliest analyses, 1964-71 and 1972-79, showed hepatocellular and oesophageal
cancers to be the most frequent
cancers. The final analysis, for 1989-96, however, shows marked temporal changes in the relative position of four
cancers or grouped
malignancies: respiratory
cancer up by 236%,
hepatocellular carcinoma down to 32%, oesophageal holding steady, and lymphatic system
cancers up by 420%, almost certainly because of association with HIV/
AIDS infection. Significant geographical variations occurring between the home areas of the miners are important, as mining operations have little to do with the
cancers that develop. The causes are essentially socio-environmental rather than occupational, and this means that the rates of the major
cancers in the miners are surrogate measures of the same
cancers in the home areas.