Similar to you I had two lumpectomies - one for diagnostic purposes then the second to get clear margins which included sentinnel lymph node removal. After that I met with a radiation oncologist and had 15 sessions of radiotherapy. Only after that did I meet with my oncologist to start hormone suppression medication.
I was told at the time that if the treatment for your type and stage of cancer is primarily surgical (in my case Stage 1 invasive lobular carcinoma) then your treatment is directed primarily by your surgeon.
Best of luck to you x