Breast conservation following neoadjuvant therapy for breast cancer in the modern era: Are we losing the opportunity?

The main rationale for neoadjuvant therapy for breast cancer is to provide effective systemic treatment while surgically down-staging the cancer. This down-staging was initially to convert inoperable patients to operable and later to increase rates of breast conservation in patients initially deemed mastectomy only candidates. Unexpectedly, in recent neoadjuvant trials lower rates of breast conservation have been observed than in past decades, despite remarkable advances in systemic therapies, which have increased pathologic complete response rates. These results point to factors aside from response and eligibility for breast conservation that may lead surgeons and/or patients to recommend and choose mastectomy. Here, we aim to examine the surgical benefits offered by the modern era neoadjuvant therapy and explore factors that have contributed to this decrease in breast conservation rates. If the main benefit of neoadjuvant therapy is to increase the opportunity for breast conservation, then our review suggests that to optimize less invasive surgical approaches, we will need to address both surgeon and patient-level variables and biases that may be limiting our ability to identify patients appropriate for less aggressive options. As an oncology community, we must be aware of the surgical overtreatment of breast cancer, especially in a time where systemic therapies have remarkably improved outcomes and responses.