Lung cancer in Africans in a South African city population in transition.

In South Africa, a study has been carried out on a series of African patients with lung cancer, who were admitted in 1994-1999 to King Edward VIII Hospital (2000 beds), and who lived in Durban (population includes approximately 650 000 resident Africans). In the urban context, Africans have recently experienced numerous changes in environmental, socio-economic and dietary factors and in other respects, thereby undergoing considerable westernization of lifestyle, compared with the past and the situation still prevailing among Africans in rural areas. In the period indicated, the mean annual number of patients admitted with lung cancer included 56 men and 9 women, thereby yielding standardized incidence rates of 15.5 and 3.5, respectively, per 100 000. While such data have their limitations, it is noteworthy that in the South African Cancer Registry for 1993-1995 the corresponding rates (pathology based) for African men and women for the whole country, rural and urban, were 11.7 and 2.6, respectively, per 100 000. In comparison, in the Registry the corresponding rates reported for white South African men and women were 22.3 and 12.3 per 100 000. With the ongoing transitional changes prevailing, most particularly concerning rises in smoking among adolescents, there is little chance of controlling further rises in the occurrence of the disease. It is significant that in the US, African Americans have been reported to have the highest rate for lung cancer in the world.

Cancer of the oesophagus in Africans in sub-Saharan Africa: any hopes for its control?

Oesophageal cancer, a highly lethal tumour, occurs to a variable extent in Africans in sub-Saharan African countries. In many, its incidence remains low, as in the Ivory Coast, Mali and the Gambia. However, in other African countries, the incidence rate has risen considerably, especially in city populations, as in Durban, South Africa, in Kyadondo, Uganda, and in Harare, Zimbabwe, rising to levels far higher than those reported in white populations. As to risk factors, in some African settings, smoking is a factor, and in others, alcohol consumption. Nutritionally, one enquiry, made in Durban, indicated the use of less-refined cereal products, with higher consumptions of vegetables and fruit, to be protective. In developed populations, protective factors are considered to be those characteristic of a "prudent" lifestyle. However, known risk factors largely fail to explain the high variability in the disease's occurrence. In seeking to combat the disease, it is thought unlikely that most Africans, especially urban dwellers, are willing to alter their lifestyle appropriately, even with the understanding that the changes would confer other protective benefits. This suggests that further rises, especially in the contexts of high incidence rates, are inevitable.

Colorectal cancer in an African city population in transition.

An enquiry has been made on a series of African patients with colorectal cancer who were admitted in 1995-1999 to Chris Hani Baragwanath Hospital (3200 beds), and who lived in Soweto (population about 1 million), Johannesburg, South Africa. In the urban context described, Africans have considerably more advantages, socio-economically, dietarily and in other respects, than their rural counterparts. The 126 patients comprised 58 males and 68 females, giving calculated incidence rates in their communities for colorectal cancer of 1.7 and 2.0, respectively, per 100,000 'world' population. In contrast, as indicated in the South African Cancer Registry for 1993-1995, the corresponding rates for white males and females were 24.7 and 19.3, respectively, per 100,000. The proportion of African patients under 40 years was 19.0%; but was only 4.0% in the white population. In contrast to this major disparity, there was only a minor interethnic disparity regarding cancers that are very common in Africans, namely, those of the oesophagus and lung. Hence, with ongoing transitional changes - in diet and other respects - the relatively high proportion of younger African patients probably indicates a rising occurrence of colorectal cancer in the urban African population.