Breast cancer is the most common invasive cancer diagnosed in women in Ireland. A comprehensive symptomatic breast service is available for women in the eight designated cancer centres. Most cases of breast cancer arise in women with no apparent close family history. The majority of people with a family history of breast cancer will not be at substantially increased risk.
Women at increased risk of breast cancer due to their family history have a specific range of strategies currently available to reduce their risk. For those for whom risk-reducing surgery is unsuitable or unacceptable, chemoprevention using drugs such as tamoxifen and raloxifene may represent a more acceptable means of risk reduction.
Tamoxifen and raloxifene reduce the risk of breast cancer for women without a personal history but who have an increased risk of the disease. As they are not currently licensed for chemoprevention in well women with a family history of breast cancer in Ireland, they can only be prescribed by a doctor following professional guidance, taking full responsibility for the decision and documenting informed consent from the patient. It is not appropriate to offer them to all women aged over 35 years with a family history of breast and related cancers. Drug licensing in Ireland is the responsibility of the Irish Medicines Board.
All drugs have side effects and risks which are particularly important when they are being used to prevent other diseases. Discussion and information should include the side effects of drugs, the extent of risk reduction, and the risks and benefits of alternative approaches, such as risk-reducing surgery and surveillance. Discussion in relation to risk of cancer of the lining of the womb, or blood clotting and in relation to bone health are of particular importance for tamoxifen and raloxifene.
The communication of information on cancer risk and carrier probability is complex. There is a degree of uncertainty with respect to the probability of inheriting a predisposing genetic mutation, of gene penetrance and hence of developing cancer. People who are concerned about a family history of breast cancer may require information to help them deal with the complex medical and social choices linked with different levels of breast cancer risk management options, and support to cope with the associated uncertainty and anxiety.
The National Cancer Control Programme will be examining the most recent guidance, published this month, on Familial Breast Cancer from the National Institute for Health and Care Excellence in the UK in relation to the management of chemoprevention and other aspects of the care of patients with a family history of breast cancer.