Advances in reconstructive breast surgery with new materials and techniques now allow us to offer patients the best possible cosmetic results without the risks associated with oncological control of the disease. These advances, in both oncological and plastic surgery, have led to a new field, oncoplastic breast surgery, which enables us to undertake large resections and, with advance planning, and prevent subsequent deformities. This is particularly important when more than 30% of the breast volume is removed, as it allows us to obtain precise information for conservative surgery according to the site of the lesion and to set the boundary between conservative surgery and mastectomy.