What Medication Is Usually Given After Lumpectomy For Mucinous (colloid)

What medication is usually given after lumpectomy for mucinous (colloid) carcinoma and sentinel node removal? My doctor told me I would need to take an aromatase inhibitor, Letrozole and Prolia. He told me I would need radiation for 4-6 weeks but I would not need chemotherapy. When I researched the drug, Letrozole, it was listed as a chemotherapy drug.