How do you tell a 13yr girl she will lose her breast?

I just found out that my 13 yr old neice has a 3 1/2 in. tumor in her breast. Her dad is dying of Brain cancer. The doctor told my sister that they will need to remove my niece's breast. How do you explain this to a 13yr old Child??? This is the 2nd opinion that my sister got for her daughter. Now we dont know that the tumor is malignate. But the tumor is taking up most of the breast. So the Doctors said this is what has to be done.

Please give me a anwser, so I can help my sister, explain this to her little girl.

What a difficult situation. Ask your sister to change eating habits in the family and start eating more Living Food to prevent relapse. Tell the girl the truth, but explaine to her that she might have a plastic surgeon restore her breast afterwards. Be with her and listen to her feelings.