Histologically diagnosed cancer in South Africa, 1987.

The National Cancer Registry collects information on cases of histologically diagnosed cancer via a country-wide network of private and public pathology laboratories. Minimal age-standardised incidence rates (ASIR, world standard) per 100,000, excluding basal and squamous cell skin cancers, for white, coloured and Asian males were 195.9, 76.2 and 82.9 respectively, and for females 161.8, 68.8 and 81.1 respectively. The oesophagus was the commonest site of cancer in black males, comprising 25.2% of all cancers in this group, and the cervix was the commonest site in black females (31.6%). Basal and squamous cell skin cancers were the leading cancers in white males (ASIR 191.9) and females (ASIR 96.9). Despite limitations, especially in data for blacks, rates for oesophageal, cervical and skin cancers rank among the highest in the world. The lung was the leading site of cancer in coloured males (ASIR 13.8) but this cancer is underestimated in all populations. Reasons for underestimation of cancer incidence include the use of non-histological methods for diagnosing cancer (cytology, radiographs, clinical examination) and variable access of populations, especially blacks and coloureds, to laboratory diagnostic facilities.