Purpose of the Review <p>To review the relative effectiveness of breast conservation surgery compared to mastectomy in the treatment of early-stage breast cancer.</p> Recent Findings <p>Since the introduction of lumpectomy with radiation or breast conservation therapy (BCT) as a treatment option for early-stage breast cancer in the 1980s, numerous studies have shown equivalent survival outcomes for the two treatment options. Multiple recent retrospective reviews have suggested that there may be a survival benefit to BCT compared with mastectomy, although these findings have been challenged in studies using the technique of propensity score matching. In addition, when considering if the treatment options are equivalent, it is important to also consider toxicity and quality of life as well as survival outcomes. While difficult to measure, several studies have demonstrated better long-term quality of life outcomes with breast conservation.</p> Summary <p>Multiple recent retrospective studies have demonstrated improved survival-related outcomes with BCT compared to mastectomy, although no prospective trial has demonstrated a difference. However, toxicities from radiation therapy have improved with newer techniques, and quality of life has been shown to be better with BCT.</p>