Breast cancer tumors treated with neoadjuvant chemotherapy may have higher risk of local recurrence after breast-conserving therapy than tumors treated with adjuvant chemotherapy, according to research published in The LANCET Oncology (online December 11, 2017; doi:10.1016/S1470-2045(17)30777-5).
Neoadjuvant chemotherapy for early breast cancer is likely to make breast-conserving surgery more feasible and to more likely to eradicate micrometastatic disease than adjuvant chemotherapy. However, the long-term benefits and risks of neoadjuvant chemotherapy have yet to be studies extensively.
The Early Breast Cancer Trialists’ Collaborative Group (United Kingdom) conducted a study to determine the long-term outcomes and risks of neoadjuvant chemotherapy and the influence of tumor characteristics on outcomes. Researchers performed a collaborative meta-analysis of individual patient data from 4756 women in 10 randomized, relevant clinical trials.
Primary outcomes of the study included tumor response, extent of local therapy, local and distant recurrence, cancer-related mortality, and overall mortality.
After a median follow-up of 9 years, researchers reported that 69% of patients allocated to neoadjuvant chemotherapy had a complete or partial clinical response. Additionally, these patients had an increased frequency of breast-conserving therapy (65% vs 49% of those treated with adjuvant chemotherapy).
Researchers reported that neoadjuvant chemotherapy was associated with more frequent local recurrence than was adjuvant chemotherapy. The 15-year local recurrence rate was 21.4% for those receiving neoadjuvant chemotherapy, compared with 15.9% for those receiving adjuvant chemotherapy. No significant difference was observed between the two groups for distant recurrence, cancer-related mortality, or overall mortality.
In their concluding remarks, researchers noted that tumors downsized by neoadjuvant chemotherapy may have higher local recurrence after breast-conserving therapy than tumors of the same dimensions in patients who have received adjuvant chemotherapy. “Strategies to mitigate the increased local recurrence after breast-conserving therapy in tumors downsized by neoadjuvant chemotherapy should be considered—ie, careful tumor localization, detailed pathological assessment, and appropriate radiotherapy,” they wrote.—Zachary Bessette