Having BRCA 1 increases the risk of a large number of cancers but the two most important are breast and ovarian cancer. You have already been treated for breast cancer. For preventing ovarian cancer the best option for you is to undergo bilateral oophorectomy. It is a small procedure and can be done laparoscopically . A hysterectomy will only remove your uterus and not your ovaries and so is of no use alone. You might consider removal of both your uterus and ovaries although it will have no effect on the risk of you developing ovarian cancer. But removal of ovaries is mandatory.