Dr. Robert Smith: The Identification and Management of the Patient at High Risk for Breast Cancer due to Family History
While there are a number of established risk factors associated with a greater or lesser likelihood of developing breast cancer, most have relative risks (RR) that are modest in size, and none strongly discriminate between women with and without breast cancer. One risk factor that is important and relevant in day-to-day clinical practice is a woman’s family history of breast and ovarian cancer. The proportion of women in the population with a family history of breast cancer in a first-degree relative (mother or sister) has been estimated to be approximately 8%; in series of breast cancer patients it approaches 14%. Of those who cite a family history of breast cancer in first-degree relatives, only 1% have more than one relative affected, and 0.1% of individuals have 3 or more first-degree relatives with breast cancer. Since current estimates indicate that approximately 5 - 10% of all breast cancer can be accounted for on the basis of known hereditary breast cancer susceptibility disorders, a true genetic predisposition to breast cancer based on known penetrance is distinctly uncommon in the clinical setting, and its presence generally is not signaled by the history of only one affected family member. Nevertheless, the proper assessment of family history to identify women at elevated and inherited risk requires full appreciation of the relevance and history of breast and ovarian cancer on both the maternal and paternal side of the family. However, current data tell us this is not well understood by a majority of women or their doctors. Many women do not have family structures where inherent risk is evident; family histories on the paternal and even maternal side often are not known by the patient; in clinical settings regular updates of family history are uncommon; and in the presence of a significant family history where genetic testing may be appropriate, costs logistics, and lack of acceptance of testing are additional limiting factors. New electronic risk estimation tools such as the Gail model, Claus model, BRACAPro, Tyrer-Cuzick, and BOADICEA can overcome some of these limitations, but the pathway from taking a simple family history to the competent use of these tools is not clear. As screening and surveillance algorithms increasingly are evolving and being tailored by risk, insuring that all women have regular and competent assessment of their cancer family history is a high public health and clinical priority.