Neoadjuvant Chemotherapy in Triple Negative Breast Cancer: A Systematic Review of Breast and Node Pathologic Response.

[INTRODUCTION] Pathological complete response (pCR) after neoadjuvant chemotherapy is associated with improved prognosis in patients with triple-negative breast cancer (TNBC). Differences in pathological response rates between the breast and axillary lymph nodes have prompted interest in understanding response patterns that may, in the future, inform strategies aimed at omitting axillary surgical evaluation. This systematic review aimed to describe and compare the prevalence of breast and axillary pathological responses in TNBC patients treated with neoadjuvant chemotherapy.

[METHODS] This systematic review was conducted following the PRISMA statement and registered in PROSPERO (ID: CRD498121). Searches were performed in the PubMed, Embase, and Web of Science databases. Studies that described node pathological response (NpCR) and breast pathological response (BpCR) in TNBC patients undergoing neoadjuvant chemotherapy were included. Article selection was independently performed by two reviewers using the Rayyan platform. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale.

[RESULTS] Across the included studies, NpCR rates were consistently higher than BpCR rates in TNBC patients. No study reported higher BpCR compared with NpCR. The mean prevalence of BpCR was 32% (SD 0.6), NpCR was 38.3% (SD 0.9).

[CONCLUSION] Among TNBC patients treated with neoadjuvant chemotherapy, NpCR occurs more frequently than BpCR. These findings provide a descriptive overview of current response patterns and may inform future research exploring the safety of omitting axillary surgical evaluation. Factors beyond tumor subtype likely influence response patterns, indicating the need for further research to identify predictive biomarkers and optimize treatment strategies.