Familial occurrence of cancer in Basel city.

The Basel Familial Cancer Study was established in 1982. Data collection and statistical analysis suggest that genetic mechanisms play an important role in most cancer types. This is illustrated in breast and colorectal cancer patients whose first degree relatives were studied. The establishment of a familial cancer registry is most helpful for cancer risk determinations, surveillance and management programmes, identification of new cancer prone genotypes and etiological family studies. The family history should be included into future cancer control activities.