Comparative Analysis of targeted molecular therapy versus Standard Care in breast cancer

Abstract

Background: Molecular subtyping of breast cancer by receptor and HER2 status has driven two decades of trials testing whether targeted agents outperform standard chemotherapy or endocrine therapy.

Objective: This analysis synthesizes randomized evidence across HER2-positive, hormone receptor-positive, BRCA-mutated, and triple-negative breast cancer to characterize how consistently targeted therapy outperforms standard care.

Methods: We compared reported progression-free survival, overall survival, disease-free survival, and pathological complete response from randomized trials of targeted agents added to or substituted for standard-care regimens.

Results: HER2-directed antibodies and antibody-drug conjugates produced cumulative survival gains over successive standards; CDK4/6 and PARP inhibitors improved progression-free survival in most but not all settings; and immunotherapy and antibody-drug conjugates improved outcomes in triple-negative disease, while genomic assays identified subsets in whom chemotherapy could be safely omitted.

Conclusions: Targeted therapy outperforms standard care across nearly every breast cancer subtype, though benefit magnitude varies by mechanism and setting, supporting subtype-specific individualization over uniform substitution.