So many things go into determining whether chemotherapy is appropriate. I had triple negative, to chemotherapy is practically a given. If you are hormone positive, then you can get information about the probability of recurrence etc... based on the pathology results from your lumpectomy. No matter what, your oncologist(s) should be able to clearly explain the reasons for their recommendations. And, you should consider a second opinion if you feel unsure about their recommendations.
TERRIFIC that your sentinel node biopsy = negative!