Abstract: Boron neutron capture therapy (BNCT) is a “dual-targeting therapy”that combines boron-containing drug delivery with neutron irradiation to specifically destroy tumor cells at the cellular level. Current clinical applications of BNCT primarily focus on refractory malignant tumors, such as recurrent metastatic head and neck cancer, recurrent gliomas, and cutaneous malignant melanomas. Multiple tumor types, including breast and lung cancers, have recently been included in BNCT clinical trials. Among these, 4-Borono-L-phenylalanine (BPA) can enter tumor cells via L-type amino acid transporter 1 (LAT1). Elevated LAT1 expression in HER-2 overexpressing and triple-negative breast cancer cells provides a sound theoretical basis and indicates promising application potential for BPA in treating refractory breast cancer. This review summarizes the physical and biological foundations of BNCT, describes the latest advances in basic and clinical breast cancer research, and discusses mechanisms, efficacy, and future directions for BNCT research.