Background, rationale and protocol for a case-control-family study of breast cancer

Historically, familial aggregation of breast cancer has been addressed either by genetic studies of extended pedigrees in which there are many cases of cancer, or by epidemiological case-control studies which measure family history by unverified self-reports of cancer in relatives. Recent identification of genetic loci involved in breast cancer susceptibility (BRCA1, p53), and recognition of the need to study the roles and interactions of genetic and environmental risk factors concurrently, have led to the development of case-control-family designs. We present here the aims, rationale and protocol for one such population-based study being conducted in Melbourne and Sydney, Australia. This approach allows the strengths and roles of genetic and environmental risk factors to be studied within an epidemiological setting, and has the potential to address the consequences for public health of new molecular genetic findings.