The Metaplastic Conundrum: A National Cancer Database Analysis of Metaplastic versus Triple-Negative Ductal Breast Cancer
摘要
Historically, treatment approaches for metaplastic breast cancer (MpBC) have mirrored that of triple-negative ductal breast cancer (TN-IDC), yet MpBC has persistently worse survival. This study describes rates and response to neoadjuvant systemic therapy (NAC) for MpBC and evaluates survival between triple-negative MpBC (TN-MpBC), biomarker-positive MpBC (nTN-MpBC), and TN-IDC by treatment approach.
MethodsThe National Cancer Database was queried for females diagnosed with clinically non-metastatic MpBC or TN-IDC from 2011 to 2021. One-to-one propensity score matching between TN-MpBC and TN-IDC patients was performed.
ResultsOf 5575 MpBC patients, surgery and chemotherapy rates were high. For patients who received systemic therapy and surgery, an adjuvant approach was favored; however, NAC for TN-MpBC increased from 18.3 to 31.5% by 2021. Higher rates of NAC non-response and lower overall survival were found among MpBC cohorts compared with TN-IDC. For MpBC, an adjuvant approach had significantly better survival than other systemic therapy sequences. When evaluated by pathologic response to NAC, a partial or non-response had worse survival compared with complete response or not undergoing NAC. On Cox proportional hazard regression of matched patients, NAC had an adjusted hazard ratio of 2.56 (1.36–4.79) compared with not undergoing NAC.
ConclusionMpBC is predominantly treated with surgery and systemic therapy, with increasing rates of NAC for TN-MpBC. However, patients with MpBC have inferior survival to TN-IDC, and NAC for MpBC is associated with worse survival compared with other systemic therapy sequences, unless a complete pathologic response is achieved. These findings reinforce the need for systemic treatment sequence optimization for MpBC.