De-escalation and Selective Omission of Adjuvant Chemotherapy in Early Breast Cancer

The role of adjuvant chemotherapy in early breast cancer (EBC) has evolved with the advent of molecular profiling and genomic assays. While chemotherapy reduces recurrence and mortality, its benefit is not universal, and many women experience toxicity without meaningful gain. Landmark trials such as TAILORx, RxPONDER, MINDACT, POETIC, ADAPT, and PHERGain have demonstrated that genomic signatures, endocrine responsiveness, and early functional biomarkers can identify subgroups who can safely omit chemotherapy. In hormone receptor–positive, HER2-negative disease, postmenopausal women with low recurrence scores or robust endocrine response derive minimal benefit from cytotoxic therapy. In HER2-positive disease, dual-antibody strategies and positron emission tomography–adapted designs have shown the feasibility of chemotherapy de-escalation. For triple-negative cancers, immune activation signatures are emerging as potential guides for future trials. Rational omission of chemotherapy—guided by biology, age, and patient preference—reflects the principle of precision oncology that prioritizes meaningful benefit and quality of life.