About Recurrence of cancer. In 2 years?.

Respected doctor, I am studying in 12 th grade. My mother is a teacher she has dygonised from stage 2 breast cancer before 3 years at that time i was in 8 th standard I was not able to more about cancer and it's seriousness. So i just leaved it. But with in one month I was able know about it's seriousness and was worried about it. Now she is absolutely normal we are going to check up in every 6.months. Now I came to now that there chance for reccurence of the cancer can you please help me out to know more about it. If it comes back will it be consider as stage 4 cancer? How effective is Immunotherapy? Is there any new treatment method to cure stage 4 breast cancer? Is there any chance for a new vaccine in 2 years? . Doctor pls reply  I have only my mother I don't have relatives, friends or siblings. I something happen to my mother I will be an orphan so pls help me doctor. Money is not a problem I will give my life save my mothers life. Is there any new treatment out side india .