@Mrs_Katie_06, always good to question treatment with your medical team. You have advice from 2 medical teams for chemo and I would go with their advice.
Surgery and radium deal with the local stuff and chemo does help to mop up any random cells that go hide and lying doment until another day.
Having chemo is never a guarantee of cancer not coming back but from my perspective just do absolutely everything you can to stop this disease.
If you are worried about chemo write all your concerns down and have a chat with your oncologist. They will answer your questions and ally your fear.
I had 4 months of chemo and I got through that. I didn't get sick but my hair fell out and i was tired. The cancer was halted for several years so that was great.
Best wishes with your decision and treatment.