Added to DonFoo's excellent message, you should be aware that the purpose of the -platin chemo is to prevent cancer cells from dividing (reproducing) during the attack on them with radiation.

You seriously want to question your lead oncologist about this omission, and don't accept anything but a clear explanation that you are comfortable with, if they persist in not giving you the chemo.

The worst of the worst chemo is over and just a memory after 90 days.

In my view, it would be very short sighted to agree to avoid a relatively short (in the context of the rest of your life) unpleasantness in favor of a risk that could lead to a recurrence of the disease.

You do not want a recurrence, trust me on this. You are young and will throw off the effects of the treatment quickly. Don't blow your ONE chance of a long lifetime, for a reduction (NOT an elimination) of the (short lived) unpleasantness of the treatment.

Please!