Most of the time they do a OncotypeDX test to genotype your tumor. I would imagine you would be following up with your breast surgeon and he/she would be able to tell you whom you would see next The Oncotype test usually determines what treatment is needed. I saw both radiation oncologist and medical oncologist before surgery for a consult. After my lumpectomy/breast reduction I saw the radiation oncologist next. It is rather confusing, it's like what came first the chicken or the egg!
Hope that helps!