Objective. To describe the overall and age-specific incidence
rates for breast cancer and determinants of the stage of breast
cancer at the time of diagnosis in the Western Cape, South
Africa.
Methods. Data were derived from a case-control study of the
association between injectable progestagen contraceptives
and breast cancer conducted over a 4-year period from
January 1994 to December 1997. In all,485 cases were drawn
from a study population consisting of coloured and black
women under the age of 55 years, who presented with a first
occurrence of invasive breast cancer at two tertiary hospitals
in Cape Town. A questionnaire was administered and
information on a large number of variables was recorded.
Results. The 249 cases who were interviewed during the first
2 years of the study constituted the numerator for estimates
of incidence rates. The overall incidence rate was 23.1 per
lOO 000 women per year. The incidence rate for coloured
women was 25.6 per lOO 000, almost twice that for black
women (14.7 per lOO (00). The incidence rate in urban areas
was 26.6 per lOO 000, almost twice that in the rural areas (16.3
per lOO (00). Stages 1 and 2 accounted for 57.8% ofthe cases.
Early stage at diagnosis was significantly associated with a
higher educational level, membership of a medicaI aid,
residence in an urban area and a positive family history.
Conclusion. The data suggest that there is scope for
improvement in the detection of the disease through
education and access to diagnostic measures, particularly in
rural and disadvantaged populations.