Abstract
Incorporating dual human epidermal growth factor receptor 2 (HER2) blockade into neoadjuvant systemic therapy (NST) led to higher response in patients with HER2‐positive breast cancer. However, axillary response to treatment regimens, including single or dual HER2 blockade, in patients with clinically node‐positive breast cancer remains uncertain. Our study aimed to examine the pathologic axillary response according to the type of NST, that is, single or dual HER2 blockade. In our study, 546 patients with clinically node‐positive, HER2‐positive breast cancer who received NST followed by axillary surgery were retrospectively selected and divided into three groups: chemotherapy alone, chemotherapy + trastuzumab and chemotherapy + trastuzumab with pertuzumab. The primary outcome was the axillary pathologic complete response (pCR). Among 471 patients undergoing axillary lymph node dissection, the axillary pCR rates were 43.5%, 74.5% and 68.8% in patients who received chemotherapy alone, chemotherapy + trastuzumab and chemotherapy + trastuzumab with pertuzumab, respectively. There was no difference in axillary pCR rates between patients who received single or dual HER2 blockade (P = .379). Among patients receiving chemotherapy + trastuzumab, patients without breast pCR had the greatest risk for residual axillary metastases (relative risk, 9.8; 95% confidence interval, 3.2‐14.9; P < .0001). In conclusion, adding trastuzumab to chemotherapy increased the axillary pCR rate in patients with clinically node‐positive, HER2‐positive breast cancer; furthermore, dual HER2‐blockade with trastuzumab and pertuzumab did not elevate the axillary response compared with trastuzumab alone. Breast pCR could be a strong predictor for axillary pCR in clinically node‐positive patients treated with HER2‐targeting therapy.
Highlights
For downstaging primary tumors, neoadjuvant systemic therapy (NST) has been commonly used for managing patients with locally advanced breast cancer
No specific target therapy is currently available for early triple-negative breast cancer (TNBC) outside clinical trials, the development and application of human epidermal growth factor receptor 2 (HER2)-targeted drugs have improved the efficacy of NST for HER2-positive breast cancer.[7,8]
Dual HER2 blockade with trastuzumab and pertuzumab has become the most preferred therapeutic option for patients with node-positive, HER2-positive breast cancer, with clinical trials demonstrating its superiority to single HER2 blockade in terms of pathologic complete response (pCR) rate[9,10] and disease-free survival.[13]
Summary
Neoadjuvant systemic therapy (NST) has been commonly used for managing patients with locally advanced breast cancer. Robust clinical evidence suggests that patients with pathologic complete response (pCR) after NST had a superior survival outcome compared to those with non-pCR at an individual level.[1] a higher pCR rate did not automatically suggest a better survival at the trial level, NST has been the preferred option for managing human epidermal growth factor receptor 2 (HER2)-positive subtype or triple-negative breast cancer (TNBC).[2,3,4]. A previous prospective trial demonstrated a clinical benefit of adding pertuzumab to chemotherapy and trastuzumab as adjuvant therapy, for node-positive HER2 breast cancer.[13] Currently, dual HER2 blockade with trastuzumab and pertuzumab is the preferred anti-HER2 treatment option for node-positive, HER2-positive breast cancer.[14]. The association between axillary pCR and breast pCR for different treatment regimens was analyzed
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