Hi Jane,
I too asked the same question....again and again!
This is my understanding.....from my Radiation Oncoologists mouth......Radiation is used as a back up......it is done to mop up any microscopic cells not killed by chemo.....that's right chemo doesn;t necessarily wipe out all cells! (I was shocked at this too)...
.He explained to me that over many years trials have been done on BC patients....a group that only recieved chemo.....a group that only recieved rads and a group that recieved both......the success rate of cancer not returning was highest in the group that recieved both treatments...So form then on they applied both therapies to Breast Cancer patients.
He did explain that having radiotherapy can actually give you cancer, ....it can cause rib fractures....and damage other organs in the line of fire.....BUT the risks of these events even happening are so low, that the benefits far outweigh the risk.......
After much thought (and argument with my sister in law, who doesnt want me to have it, because of a bad experience with her sister in law) ...I have decided that radiotherapy as part of my treatmnet plan is paramount to ensure that I have done EVERYTHING possible for now to be rid of cancer.
It's OK to be scared, this whole thing is a nightmare...but trust that your team have consulted each other, had meetings to discuss your case and have your best interest at heart.
Hope this helps a little....
Wishing you all the best with your treatments........
Tracy