Can you go in remission more than once

Sunshineplease

My mom has been dx with breast cancer in 2002. After surgery, radiotherapy, chemo and tamoxifen she was in remission. In 2015 she was dx stage IV mets to the bones. Has been on letrozole until this summer and her cancer seemed to be dormant with the letrozole until then. It has woken up this summer (this is the way the dr put it). My question is, are there any chances it can go back asleep ? Looking for some hope and maybe even people to whom it has happened. My mom is asking God or whomever can hear us for 10 more years and when I read most posts, I dont usually see survivors for more than 5, 6 years. It has been 6 years since her stage IV dx so I am really scared and am just looking to see if it is at all possible for her cancer to go back in remission or asleep at this point.

She has radiotherapy soon, they called her yesterday to tell her she has mets in her spine and they want to act fast. For now she does not have any or much symptoms related to those mets, so we are clinging to that thinking it might mean they saw it early enough to minimize the damage and everything might go back to the way it was before the relapse…

Thank you for reading me, hoping to get positive experiences or good news through the bad