One particular medicine used to treat breast cancer, tamoxifen (eg Nolvadex D), has been shown in an American study to reduce the risk of developing breast cancer by approximately 50 per cent in women at high risk of developing the disease. Research with tamoxifen and some other breast cancer medicines is still being carried out to determine if these are suitable options for preventing breast cancer. However, tamoxifen is associated with some rare but serious side effects that may make it unsuitable as a preventive measure.Screening, as currently practised can reduce the mortality but not the incidence of breast cancer (and then only in the age group that is screened). Once a woman reaches the age of 50, she will be invited to take part in a breast screening programme. In the UK, this means having a mammogram every three years up to the age of 64, although the upper age limit of routine screening is currently being extended to 70 years throughout the UK.. The aim of screening by mammography is to pick up cancer while it is still small before it has a chance to spread. There are various reasons why women are not normally screened below the age of 50:
breast cancer is less common in younger women.
mammography is less likely to detect breast cancer in young women because the breast tissue is denser which can make breast cancer much more difficult to detect.
there is no evidence that breast screening below the age of 50 is cost effective.