My mom's came back too. She has has breast cancer twice and now it has returned a third time. Unfortunately there is no way to answer your question. For some women, breast cancer recurs - and for many others it never does. It depends a lot on the stage and type of cancer (hormone receptors, etc.) , but the way the actual cancer cells grow and behave differs in every person. I am sorry for what you and your mom are dealing with. Please know that everyone on this site understands your fear and frustration.