6 March 2019 Breast cancer currently affects 1 in every 10 women. However, as can be seen from the results of screening programmes, most breast cancers diagnosed in the early stages can be successfully treated. In about 80% of cases , breast cancer is diagnosed after the age of 50. What is the significance of genetic factors in breast and ovarian cancer? Given the high frequency of breast cancer, it is not surprising that there is at least 1 occurrence of the disease in most families. These cancers are almost always sporadic and multifactorial; that is, their appearance and progression depend on a combination of factors: Hormonal; Reproductive; Genetic; Environmental; Lifestyle-related; Others as yet unknown. The significance of genetic factors is much greater where: A large number of family members on the same side of the family (mother’s or father’s side) are affected; The diagnosis is made at a younger age; The degree of family relationship is closer; There are cases of bilateral breast cancer, breast cancer in men or breast cancer and ovarian cancer in the same family. In rare cases, accounting for less than 5% of the total number of cases, breast cancer is the result of an error in a predisposing gene. This error can be transmitted from generation to generation , giving women who inherit it a much greater risk of developing breast cancer. In addition to breast cancer, the presence of an error in a predisposing gene also increases the probability of ovarian cancer. These errors can be detected by genetic testing. However, such tests are justified only in a small number of cases in which there is a very significant family history of the condition. In most situations, breast cancer in families with various cases is not hereditary, although there may be some increased genetic susceptibility involved. The probability of a woman who has several family members with breast cancer developing the disease can be calculated using statistical data. Where this calculated risk is high, special surveillance and/or preventive measures are justified. This article was written with the support of physicians and other clinical professionals from the Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
