Hi Mita
I am not a doctor, but from what the Surgeon said to me if it was a particular type of tumour and the take it all out with clear margins, then they would just do Radiation therapy, as a precaution to help prevent reoccurrence. If they are keeping a regular I on your breasts with scans and mammograms, they would see something when it was very small and be able to deal with it quickly. So try not to worry, my cousin had a tumour taken out 23 years ago and had no chemo or radiation and she is completely fine
much love
Yvette