SL-2 Breast cancer treatment system

Surgery under general anesthesia for breast cancer was performed for the first time in Japan. Hormone therapy (bilateral ovariectomy, selective estrogen receptor modulator, LHRH analog, aromatase inhibitor, selective estrogen receptor down-regulator) has been developed for more than 120 years. Radiation therapy also has a history of more than 100 years. Anti-cancer chemotherapy has a history of about 50 years. It has been about 20 years since the development of molecular-targeted therapy began, and we have succeeded in developing therapeutic methods targeting HER2, mTOR, CDK4 / 6, PARP, PI3K, etc.in breast cancer, and immunotherapy is currently the biggest topic. Breast cancer is a highly heterogenous cancer, and multidisciplinary treatment and individualized treatment are the central concepts of treatment. Recent trends in multidisciplinary treatment are measures to promote treatment escalation, and de-escalation, ‘Do More and Do Less’, to maximize treatment benefits and minimize treatment-related toxicity and quality of life reduction. On the other hand, individualization of treatment has made great progress in the last 20years with the generalization of high-standard pathological diagnosis, characterization of tumor subtypes and prediction of prognosis and therapeutic outcomes using multi-gene assay / expression profiles. Recently, it has become possible to test pathogenic variants of breast cancer-related genes such as BRCA1 / 2 in clinical practice, and it has been applied to surgery for patients with primary breast cancer, preventive resection for reducing contralateral breast cancer, and to indicate PARP inhibitor as companion diagnostics for patients with recurrent breast cancer. These current situations and prospects will be described.