Metastatic breast cancer has gone to hip bone; prognosis?

This depends: The answer depends on many factors. How old is the persone, what other medical problems do they have, when did the breast cancer first occur, what other sites are involved, what are the characteristics of the cancer (estrogen, Progesterone receptors, her2/neu status) and what prior treatments were administered are some of the issues that factor into an answer.

No cure but manage: Omce a cancer has spread to a distant site it can never be totally eradicated or cured. There are many treatment options to help deal with symptoms and slow progression allowing extension of quality and quantity of life. Tis is especially true with bone only metastatic disease (versus other organs).