Familial breast cancer: where the clinician and basic scientist interface.

In familial breast cancer certain cardinal features have been observed: (1) An early age of onset; (2) Excess bilaterality in paired organs; (3) Vertical transmission consistent with an autosomal dominant mode of inheritance; (4) Genetic heterogeneity; (5) A more recent observation of improved survival. Approximately 18% of breast cancer patients will demonstrate familial aggregation and only 8% will meet the criteria for syndrome identification. In an analysis of 106 hereditary breast cancer patients, the average age of diagnosis was 49 years. One-third (35%) were under the age of 45 at the time of diagnosis. This genotype is transmitted in a vertical manner from one generation to the next in accordance with an autosomal dominant pattern. The five-year disease-free survivorship was found to be 65% in our familial breast cancer population. In this familial population pregnancy did not influence the natural history of breast cancer in the same manner as with sporadic breast cancer. An algorithm for the clinician encountering a patient with familial breast cancer and the unaffected relative is outlined.