Standards in adjuvant systemic therapy of breast cancer

Survival is the primary goal of adjuvant chemotherapy by curative treatment of potential micrometastases. The standard of care is a chemotherapy regimen containing anthracyclines (epirubicin and doxorubicin) and taxanes (paclitaxel and docetaxel). Possible side effects (e.g. nausea and vomiting, myelosuppression and alopecia), such as cardiotoxicity and secondary leukemia with anthracyclines, polyneuropathy for paclitaxel and hemotoxicity for docetaxel need to be discussed. The use of targeted therapies for breast cancer is steadily increasing. Trastuzumab, an inhibitor of the human epidermal growth factor receptor 2 (Her2) has been the standard medication for Her2 positive breast cancer since 2005. The dual Her2 block with pertuzumab in the neoadjuvant setting is currently used to enlarge the range of anti-Her2 targeted agents and was approved in July 2015. A wide range of antibodies influencing the cell cycle or inhibiting cell metabolism are currently under investigation in clinical studies, e.g. cyclin-dependent kinases 4 and 6 (CDK 4/6) inhibitors, poly(ADP ribose) phosphorylase 1 (PARP) inhibitors and phosphoinositide-3 kinase (PIK) inhibitors. Current therapies focus on tumor biology rather than on the tumor size alone. The therapy of subgroups with breast cancer, such as pregnant, fragile and male patients still represents a special challenge.