There are a few advocates of maintaining progesterone in elder women (for various reasons) and supplementing the diet with iodine to avoid fibrocystic breasts. These seem like not overly difficult steps to take and perhaps of particular interest to transwomen on HRT.

While estrogen treatment may increase the statistical percentage of certain types of breast cancers, the overall percentage of cancer in the TS HRT community is very low, where a single case can have substantial impact on the percentages published. Another way to look at this is HRT may reduce other forms of risk, such as heart disease, or suicide. From my research, so far, the research is too sparse to divine any real meaning. As with most medicines it's important to use the lowest acceptable dosage of HRT to confer the lowest possible risk. Remember physicians are required by law to provide their patients with all reasonable risk information related to their therapy. Just read the possible side-effects of Wellbutrin;)