Clinicopathological Features and Prognosis of Metaplastic Breast Carcinoma: Experience of a Major Chinese Cancer Center

Metaplastic breast carcinoma (MBC) is a rare heterogeneous group of primary breast malignancies, with low hormone receptor expression and poor outcomes. To date, no prognostic markers for this tumor have been validated. The current study was undertaken to evaluate the clinicopathologic characteristics, the response to various therapeutic regimens and the prognosis of MBCs in a large cohort of patients from Tianjin Medical University Cancer Hospital in China. Ninety cases of MBCs diagnosed in our hospital between January 2000 and September 2014 were retrieved from the archives. In general, MBCs presented with larger size, a lower rate of lymph node metastasis, and demonstrated more frequent local recurrence/distant metastasis than 1,090 stage-matched cases of invasive carcinoma of no specific type (IDC-NST), independent of the status of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 expressions. The five-year disease-free survival (DFS) of MBC was significantly worse than IDC-NST. Using univariate analysis, lymph node metastasis, advanced clinical stage at diagnosis, high tumor proliferation rate assessed by Ki-67 labeling, and epidermal growth factor receptor (EGFR) overexpression/gene amplification were associated significantly with reduced DFS, while decreased OS was associated significantly with lymph node metastasis and EGFR overexpression/gene amplification. With multivariate analysis, lymph node status was an independent predictor for DFS, and lymph node status and EGFR overexpression/gene amplification were independent predictors for OS. Histologic subtyping and molecular subgrouping of MBCs were not significant factors in prognosis. We also found that MBCs were insensitive to neoadjuvant chemotherapy, routine chemotherapy, and radiation therapy. This study indicates that MBC is an aggressive type of breast cancer with poor prognosis, and that identification and optimization of an effective comprehensive therapeutic regimen is needed.