Breast cancer has been recognised since antiquity, and as the disease’s nature changed over time, so did the approach to treatment. Hippocrates classified breast cancer as a humoral illness in 460 BC, but following much research, it is now thought to have localised causes and systemic origins. Halsted radical mastectomy was the “established and standardised operation for cancer of the breast in all stages, early or late” for the majority of the 20th century.Recent discoveries on the biology of tumours and their behaviour raised the possibility that less invasive surgery could be just as successful as more involved ones. The scope of surgical resection in the breast and axilla was eventually further reduced with the use of adjuvant therapy, such as radiation and systemic therapy, ushering in an era of breast conservation.In an effort to shorten treatment times and minimise normal tissue harm, breast cancer radiation therapy has progressed from 2D to 3D conformal and accelerated partial breast irradiation. A proven method of treating breast cancer is systemic therapy, which includes biological agents, hormone therapy, and chemotherapy. The care of breast cancer today is predicated on the quickly developing and more comprehensive research on the cellular, molecular, biochemical, and genetic underpinnings of the illness.The task ahead is to leverage this understanding to forecast treatment outcomes, create new treatments, and quickly implement more cutting-edge biologic therapies.