I think that the future possible regret is a big consideration. Your posts seem to indicate that you feel that 2% is not significant, and that is one issue. Of course 2% discount on the price of a handbag is not significant, but 2% of pupils in a large city school of 1000 pupils would be 20 kids. If a gunman entered the school and shot dead 2% of the pupils...that would be twenty dead children. Suddenly that 2% seems large. Same with this, the 2% doesn't matter, unless you're one of them. Added to this is that you don't know in advance and even then, it may still return chemo or not. The question then is this. If you have the chemo, and it comes back anyway, you could at least say to yourself that you had done all that you could have and get on with treatment for stage 4 (or not). But if you don't have the chemo, and it does return, will you still be happy with your choice, or would that little voice continue to whisper in your mind..."If I'd had the chemo, would I have been one of those percentage ...if only there was a stop and rewind button to push?"