Overuse of Neo-adjuvant Chemotherapy for Primary Breast Cancer

In recent years, there has been a wider use of chemotherapy in the pre-operative setting for breast cancer (i.e., as neo-adjuvant chemotherapy). Most clinicians would agree that neo-adjuvant chemotherapy is justified for patients with inflammatory breast cancer, locally advanced breast cancer, or patients with large tumors and small breasts who are keen to undergo breast-conserving surgery. However, in the USA and many other western countries, neo-adjuvant chemotherapy is now used for greater numbers of breast cancer patients who do not fall within these categories. Yet, randomized trials have consistently shown that there are no differences in overall survival (OS) between breast cancer patients treated with neo-adjuvant chemotherapy versus adjuvant chemotherapy. However, neo-adjuvant chemotherapy may increase the risk of loco-regional recurrence after breast-conserving surgery, perhaps because of an increased risk of leaving behind residual tumor foci. Moreover, the effects of neo-adjuvant chemotherapy on the primary tumor does not appear to be a suitable way for assessing the potential overall benefits of systemic therapy regimens on distant micrometastases and risk of death. Yet, based on the results of the KATHERINE and CREATE-X trials, one might argue that neo-adjuvant chemotherapy should be recommended for patients with HER-2-positive and triple-negative tumors to identify the subsets of patients who do not achieve pathologic complete response (PCR). Patients with HER-2-positive tumors who do not achieve PCR may benefit from additional treatment with T-DM1, and those with triple-negative tumors who do not achieve PCR may benefit from additional treatment with capecitabine.