Multimodal De-Escalation Strategies in Early Breast Cancer.

The excellent cure rates documented in clinical trials today constitute a very high bar for attempts to de-escalate therapy for early-stage breast cancer (EBC). Moreover, any therapy de-escalation must be made in the context of an optimal multimodal treatment concept as de-escalation of one modality should not be met by escalation of another. In surgery, omission of sentinel lymph node biopsy can now be safely offered for patients with low-risk hormone receptor-positive/human epidermal growth factor receptor 2-negative (HER2-) disease. After neoadjuvant therapy, adapting surgical and/or radiation therapy (RT) treatment steps to systemic treatment response has already become a reality, yet technical quality assurance is mandatory. Increased use of novel targeted agents in eBC requires adaptation of RT timing that has been addressed by current consensus recommendations. Last but not least, omission of chemotherapy (CTx) is a key question for patients and their physicians in hormone receptor-positive/HER2- EBC. In patients with zero to three involved lymph nodes, gene expression assays safely allow CTx omission. Endocrine response assessment, that is, Ki67 determination, after a short 4-week endocrine therapy before surgery adds important information, particularly for premenopausal patients. The overall goal of therapy de-escalation is to reduce treatment burden without compromising patient outcomes. Thus, de-escalation concepts overall, as well as biomarkers used for therapy de-escalation, need to be evidence-based and validated by prospective clinical trials.