My renovating buddy Mike Holmes of Restovate in Toronto (before he went on TV) was into the creation of a new basement suite so I asked him to show us as he cut in for the rough plumbing for the toilet. So he jack hammered up the floor, then dug a bit more (as is common), then he discovered that he had exterior ABS not PVC under the floor. So he had to go out and get some special ABS/PVC connectors, and use special solvent to join these incompatible materials together. As Mike says, there are always surprises under concrete floors. But he got it in, perfectly lined up according to his plan and the new concrete back on.
It won't work all the time, but you might want to check out any plumbing store that sells German toilets, or special order the American Standard one that I show in the photo. Take a close look at the photo and you will see that the drain exists out the back, not the bottom, either totally avoiding or at least minimising cutting through the concrete. All floors in Germany are concrete, so they never go through the floor under the toilet -- they go back into the wall and down. You can also get institutional toilets that hang on the wall and exit through the back as well, allowing for installing it at any height you may want, like for wheelchair access.