Will radiation pills for hyperthyroidism wake up cancer cells?

my mother is 66 years old and she needs to have her thyroid removed because it's toxic. she's been to 2 doctors now and they recommended different procedures. doctor #1 recommended radiation pills while doctor #2 recommended surgery because if she takes radiation pills, he said that there is a risk of waking up cancer cells that we all have in our bodies. Is that true? I have been searching the Net for risks of radioactive pills and so far there has been no mention of this "waking up of cancer cells". I hope someone can verify if what doctor #2 is saying is true? Thanks.