Neils Bohr once said prediction is difficult especially of the future. The problem with risk prediction of any disease acquisition is that only hindsight is 20/20, and although your risk may be low, if you get the disease, your acquisition is 100%.So physicians feel it’s important to try prediction, as that improves care, but patients (rightfully) often want more.
If we predict that you are more at risk for breast cancer, there is something positive you can do to prevent the disease. Tamoxifen is a medication that can help to prevent breast cancer; who should take it and when to take it is the question for you and your gyno. Traditionally, gynos have relied on the Gail scale to calculate risk.
For some women there is a very short sojourn between atypia and cancer, so if you wait until you have precancerous changes (like detected on a Halo or a biopsy), there may not be enough time to intervene and prevent the disease. Taking Tamoxifen to prevent cancer is called chemoprevention: the thesis behind this chemoprevention is that this medication is antiestrogen. And it is thought that estrogen is related to breast cancer cell growth.
But in order for estrogen to affect this process, the estrogen molecule has to bind to the breast cell to change it, and when tamoxifen is given, the process, in essence, is interrupted. In the studies of this medication, there were some polyps of the lining of the uterus, and there were some cases of blood clots, and there was an increased risk of having a cataract. Patients can also consider raloxifene (Evista) as a (more expensive) alternative, especially if they need bone protection, as the mechanism of protection is similar: about 55% of the cases are prevented. In fact it is estimated that only about 10% of women that could benefit from these therapies are even getting the therapy. Not every woman is a candidate, and it's something to gab with your own gyno about.