The potential of the Familial Cancer Registry for anticancer research and medical practice.

The Basel Familial Cancer Registry was established in 1982. Detailed pedigree data are obtained from 200 cancer patients every year. Analysis of familial clustering is performed by comparing the tumor spectrum of different family groups defined by the probands' cancer sites and by comparing tumor incidence and spectrum in the families with tumor incidence and spectrum in the population (data from the population - based Basel Cancer Registry). A nonrandom distribution of cancer in first-degree relatives of cancer patients and significant familial cancer aggregations point to underlying genetic mechanisms. The association of cancer and minor anomalies in children points to common mechanisms of carcinogenesis and teratogenesis. Laboratory investigations revealed an impaired DNA-repair synthesis in lymphocytes of breast cancer patients and their relatives. Patients and their relatives are counselled. They show interest and cooperate well. An early detection program is being developed in colorectal cancer. Administrative work is centrally organized and the screening work is performed by the family physicians.