22% of people diagnosed with Stage 4 breast cancer have no evidence of cancer five years later. My understanding of my reading of research is that, if you have no trace of cancer at that five year mark, you are (very likely) cured of that cancer. There is growing evidence that the same is true at the 3 year mark. You can get a brand new cancer, the same way the first one popped up (but so can anybody). Stage 4 means the cancer has spread to other parts of the body. A lot can depend on where the cancer spread, some areas of the body can withstand vigorous removal methods better than others. (All this is as of this writing 4/18/2018.)
The chance is always there. Please do not forget that there are always some options and special approaches for its treatment. I recommend to have a look at the article about stages of breast cancer myallamericanhospice.com/stages-of-breast-cancer/ and be on the safe side with that respectful medical website. Hope it can help you