Table 3_Metaplastic breast carcinoma versus triple-negative breast cancer: distinct metastatic patterns and inferior overall survival in a matched retrospective cohort study.xlsx

Relative to TNBC, MBC more often presented as grade III disease (88.9% vs. 28.7%, P < 0.001) and T3–T4 disease (33.3% vs. 11.1%, P = 0.007), while nodal involvement was less common (25.9% vs. 51.9%, P = 0.019). Proliferative activity was greater in MBC, with a higher Ki-67 index (54.0 ± 16.3% vs. 43.5 ± 22.0%, P = 0.011) and a higher proportion of tumors with Ki-67 ≥ 30% (100.0% vs. 81.5%, P = 0.020). During follow-up, recurrence or metastasis (25.9% vs. 8.6%, P = 0.041) and distant metastasis (22.2% vs. 2.5%, P = 0.003) occurred more often in MBC.

DFS was numerically shorter in MBC but was not statistically different (P = 0.200), whereas OS was significantly poorer (P = 0.038).</p>Conclusion<p>In this matched cohort, MBC showed a profile of high-grade histology, greater tumor burden, active proliferation, limited nodal spread, and frequent distant metastasis. The results indicate that MBC should not be treated simply as another presentation of TNBC, but as a high-risk entity requiring careful assessment of metastatic risk.</p>