As I have said, you are assuming that "one cannot reverse the effects of late stage very aggressive cancer". Likewise, a few decades back, if people also assumed that first stage cancer is "death-bed stage" which "you cannot reverse as the cancer cells are just too far gone to stop", there would be no radiotherapy, or other forms of methods for a remission to occur. There will certainly be no forms of remission for cancer, and people will most likely take euthanasia as they find the future seems dim.