Hi I was diagnosed with Early Stage invasive ductal carcinoma, was given a choice of lumpectomy plus radiotherapy and then chemotherapy or mastectomy and straight into chemo. I believe radiotherapy "mops up" potential cancer cells not collected by the lumpectomy in the local area whilst a mastectomy removes the whole lot.... this is based on negative sentinel node involvement. However some people have had mastectomy, radiotherapy and then chemo as well....so it's well worth discussing with your oncology team as your grade of tumour may play a factor..