Metaplastic Carcinoma of the Breast Is More Aggressive Than Triple-negative Breast Cancer: A Study From a Single Institution and Review of Literature

Abstract

We aimed to describe our experience with metaplastic breast carcinoma (MBC), evaluate its clinical outcome compared with triple negative breast cancer (TNBC), and provide a through and comprehensive review of the literature to date. We reviewed MBC cases (n=46) from our institution. The following variables were recorded, tumor histologic subtype, Nottingham grade, tumor size, lymph node status, TNM-stage, biomarkers profile, patient’s age and race, therapy modality (chemotherapy and radiation), and survival [disease free survival (DFS) and overall survival (OS)]. The clinical and pathological data for TNBC (n=508) cases was extracted from the BC database. In order to compare the survival between MBC and TNBC, a subgroup of MBC (n=40) were matched with TNBC (n=40) cases based on known prognostic confounders. There were 17 of 46 (37%) cases with mesenchymal differentiation, 12 (26.1%) squamous cell carcinoma, 14 (30.4%) spindle cell carcinoma, and 3 (6.5%) mixed type. MBC presented at a more advanced stage than TNBC (p=0.014) and was more likely to recur 34% vs. 15.5% (p= 0.004). More MBC patients died from disease than TNBC, 29% vs. 16% (p= 0.05). In the multivariate analysis, MBC had about twice the risk of local recurrence than TNBC (95% CI 1.01–3.83, p=0.05). MBC patients had worse DFS and OS than the matched TNBC patients (p <0.001 and p=0.033, respectively). A review of literature comparing MBC vs. TNBC is presented. Our results suggest that MBC is clinically more aggressive than TNBC. Further studies may help delineate the differences between these two entities.

Outcomes after Treatment of Metaplastic Versus Other Breast Cancer Subtypes

“…TNBC tends to have a worse prognosis than other types of BC, [20][21][22][23] and the notion that metaplastic BC is more aggressive than TNBC has been corroborated by multiple smaller, retrospective investigations. [4,8,9,24] Such studies have shown similar patterns of diagnosis at advanced stages for metaplastic BC versus TNBC, owing to higher rates of cT3-4 disease rather than nodal involvement, [9,24] and in a single-institution review of 46 cases of metaplastic BC, patients with metaplastic BC had a significantly higher risk of local disease recurrence (30% vs. 15%; P=0.004). These features ultimately correlated with inferior 5-year disease-free survival rates (30% vs. 90%; P<0.001) and OS rates (65% vs. 87%; P=0.002) for patients with metaplastic BC relative to TNBC.…”

Assessment of outcomes and novel immune biomarkers in metaplastic breast cancer: a single institution retrospective study

“…Such results are similar to our multivariate analysis that showed no significant difference in OS and DDFS between the two cohorts. However, other investigations have demonstrated unfavorable results for patients with MBC compared to those with TNBC or hormone receptor-negative IC-NST [6,[36][37][38]. The varying results highlight the need for additional larger retrospective studies to understand the biology and best treatment practices to treat patients with MBC.…”

Comparative prognostic analysis for triple-negative breast cancer with metaplastic and invasive ductal carcinoma

“…Up to now, only a few reports have attempted to investigate the differential prognosis and predictive factors that make MBC different from more common types of malignant breast cancer 17–20. For example, a study by El Zein et al including 46 cases of MBC showed that metaplastic breast cancer presented at a more advanced stage than TNBC and was more likely to recur, indicating MBC was clinically more aggressive than TNBC 20. Jung et al reported a study containing 35 patients with MBC and 2839 with IDC, and showed that patients with MBC presented with larger tumour size, more distant metastasis at the first diagnosis, higher histological grade and poorer prognosis 18.…”