Breast Cancer Subtypes and Biomarkers
Modern breast cancer treatment is guided by tumor biology: Luminal A/B (ER+/PR+), HER2-positive, triple-negative (TNBC) and HER2-low. All patients in Istanbul undergo standard ER, PR, HER2 IHC/FISH, Ki-67 and NGS genomic profiling.
HER2-Positive: The Most Dramatically Improved Subtype
HER2+ breast cancer is now highly curable. Trastuzumab + Pertuzumab + Taxane in early stage can achieve cure. Post-neoadjuvant residual disease uses T-DM1 (Kadcyla), then T-DXd (Enhertu) achieving excellent control. Tucatinib + Trastuzumab + Capecitabine for brain metastases achieves ~90% brain control.
T-DXd (Trastuzumab deruxtecan) is now approved for HER2-low (IHC 1+ or 2+/FISH-) AND HER2-ultralow patients. This covers 60-70% of all breast cancer patients — a massive expansion of eligibility.
Triple-Negative Breast Cancer: Immunotherapy
TNBC patients with PD-L1 ≥10%: Pembrolizumab + chemotherapy as standard first-line. BRCA1/2 mutation: Olaparib (PARP inhibitor) is a key option. High-risk TNBC: adjuvant Capecitabine improves 5-year survival.
Breast-Conserving Treatment and MR-Linac
Breast-conserving surgery (lumpectomy) + radiotherapy achieves equivalent oncological results to mastectomy. With MR-Linac, 5-fraction accelerated partial breast irradiation reduces treatment to 2 weeks. Sentinel lymph node biopsy is standard.
Breast cancer treatment in Istanbul costs 50-80% less than USA. 6-cycle chemotherapy: $5,000-15,000 (USA: $30,000-100,000). T-DXd: $15,000-25,000/3 months (USA: $80,000+). MR-Linac RT: $8,000-18,000.