From scientific promise to clinical reality: Nanomedicine for breast cancer.

Breast cancer is still one of the most important health burdens worldwide, with incidence and mortality rates increasing, especially in Asia and Africa. As conventional therapeutic approaches, including endocrine therapy, chemotherapy, surgery, and radiotherapy, have developed, their limitations were gradually identified from systemic toxicity to therapeutic resistance. Nanomedicine has emerged as a revolutionary approach where nanotechnology is exploited for precise drug delivery, improving bioavailability while reducing adverse effects. The passive and active targeting mechanisms are involved in the nanoparticle-based drug delivery systems (DDS), which enhance the therapeutic outcomes. Passive accumulation of nanoparticles in tumours is facilitated by the enhanced permeability and retention (EPR) effect, while active targeting is enhanced by the use of ligand-functionalised nanocarriers. Stimuli-responsive nanomedicines further optimise drug release, with triggers from the tumour microenvironment, including pH and reactive oxygen species. Furthermore, nanomedicine has been playing an important role in overcoming radio-resistance and improving immunotherapy efficacy. Nanomedicine, though very promising, has its problems: high expenditure for research and development, legislative barriers, and public scepticism. Overcoming these issues requires resolving nanotoxicity and making the processes capable of large-scale manufacturing. Because cancer nanomedicine is well on its course toward precision medicine, interdisciplinarity at work, and strong policy support should be seen for the fullest deployment of this concept in the treatment of breast cancer.