Classical studies comparing breast-conserving therapy (BCT) and mastectomy (Mx) focused on the non-inferiority of BCT in terms of survival outcomes. However, recent large retrospective studies have provided evidence that BCT could confer a survival advantage over Mx. The prognostic benefit of BCT was observed in all molecular subgroups, including triple negative breast cancer, and also in young patients affected from the disease, who are often submitted to Mx irrespective of tumor size. This new concept, regarding the prognostic importance related to the type of surgical treatment of breast cancer, is of particular relevance in current times. In fact, in the last two decades there has been a rise in Mx rates in BCT-eligible women, as well as a rise in bilateral mastectomy in patients with unilateral breast cancer. This phenomenon occurs despite lack of scientific evidence supporting the necessity of a more extensive surgery, and is primarily a patient-driven trend. The results of recent studies, demonstrating that BCT achieves better overall survival than Mx, should be incorporated in the multidisciplinary decision-making process. Patients with early breast cancer for whom either BCT or Mx are surgical options, should be properly informed that the prognosis of their disease is largely dependent from the biological behaviour of the tumor, and that Mx should not be considered equal to BCT in terms of survival. The present review underscored that BCT, when feasible, should be considered the option of choice also due to its advantage in survival outcomes.