In the late 19th century, William Halsted proposed the radical mastectomy, which became the standard surgical treatment of breast cancer for nearly 100 years. Later in this period, theories suggesting that breast cancer was a systemic disease at inception were championed by Bernard Fisher. This alternative hypothesis of biological predeterminism was based upon results of randomized clinical trials comparing breast conserving therapy with mastectomy, which showed similar overall survival outcomes. Nonetheless, data from meta-analyses suggest that inadequate local therapy can increase risk of local recurrence, which can subsequently increase mortality. In this review, the authors provide an historical account of how local therapy of breast cancer has evolved in the face of improved adjuvant therapies and better understanding of disease biology.