"As an Oncologist, I am ultimately the one from whom she can get a perspective on her risks if she were to do nothing. But since they are neither 0% nor 100%, I would invite her parents to take part in the discussion. Also, there is much more than her childbearing at stake here, but perhaps many children, grandchildren, family legacy, and so on. And since even high-risk genetics seldom sees malignancy begin at this age, I would recommend an agreed-upon surveillance protocol specifically for her so that we could act at the earliest opportunity if necessary."

This question is probably jumping the gun and testing how careful you would be to avoid skipping steps on important and controversial subjects. You cannot go wrong citing protocol, if there is any; if there aren't any, you can't go wrong recruiting help from others more appropriate for such decisions, especially when the dilemma is bigger than you (which this one is).

"I would involve a multidisciplinary team made up of myself, her primary doctor, a social worker, a psychologist, and an ethicist. Together I would trust we could steer her correctly for such a permanent life-decision."