The objective of our study was to conduct a cost-effectiveness (CE) study of combined everolimus (EVE) and exemestane (EXE) versus the common clinical practice in Greece for the treatment of postmenopausal women with HR+/HER2- advanced breast cancer (BC) progressing on nonsteroidal aromatase inhibitors (NSAI). This evidence concerns the gene CYP19A1 and breast carcinoma.