Comparison of outcomes between metaplastic and triple-negative breast cancer patients

Abstract

Purpose Metaplastic breast cancer (MBC) is a rare, aggressive variant of breast cancer that has been associated with poor clinical outcomes, as has triple-negative breast (TNBC) cancer. Limited studies compare the clinical characteristics and prognosis of MBC to TNBC. This study uses a large, contemporary US cancer database to compare clinical characteristics and survival outcomes for patients with MBC to those with TNBC. Methods The National Cancer Database was queried for women with cT1-4N1-3M0 MBC or TNBC diagnosed between 2004 and 2013 and treated with definitive surgery. Chi-squared analysis was performed to determine differences between the cohorts. Kaplan-Meier curves compared overall survival (OS), and Cox regression determined patient factors associated with OS. Results Altogether, 55,847 patients met the inclusion criteria; 50,705 (90.8%) had TNBC and 5,142 (9.2%) had MBC. Most patients had no comorbid conditions (82%), N0 disease (71%), poorly differentiated histology (77%), received chemotherapy (87%), and received radiation therapy (60%). Amongst all patients, patients with TNBC disease were observed to have greater OS than those with MBC (5-year OS 72.0% vs 55.8%, p < 0.001). The greater observed OS for patients with TNBC persisted when controlling for stage and when comparing propensity score matched cohorts. On Cox regression, lower age, T1 status, N0 status, chemotherapy, TNBC disease, and radiation therapy (RT) were associated with improved OS. Conclusions MBC had an association with poorer OS compared to TNBC, while RT and chemotherapy receipt were associated with improved OS for patients regardless of stage. Further studies are needed to corroborate the conclusions herein.

Metaplastic breast cancer: Prognostic and therapeutic considerations

“…A major Texas study collected 5142 cases of MBC and 50,705 TN ductal cancers from the National Cancer Database, with an OS of 55% in MBC and 72% in TN lesions. That study documented worse prognosis in MBCs compared with other TN ductal tumors, although adjuvant chemotherapy and RT improved prognosis 3 . The frequency of MBC identified, however, was around 10%, which may be excessive, as it is estimated that it does exceed 5% 6 …”

“…Metaplastic breast carcinoma (MBC) is a rare condition accounting for 0.2-5% of all breast tumors. [1][2][3] The current World Health Organization (WHO) identifies different histological patterns of MBC: low-grade adenosquamous carcinoma, fibromatosis-like metaplastic carcinoma, squamous cell carcinoma, spindle cell carcinoma, metaplastic carcinoma with mesenchymal differentiation, mixed metaplastic carcinoma, and myoepithelial carcinoma. 4 Compared with the other histotypes of breast cancer, MBC most commonly shows a triple-negative (TN) phenotype, due to the absence of expression of the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2.…”

“…Metaplastic breast carcinoma (MBC) is a rare condition accounting for 0.2‐5% of all breast tumors 1‐3 . The current World Health Organization (WHO) identifies different histological patterns of MBC: low‐grade adenosquamous carcinoma, fibromatosis‐like metaplastic carcinoma, squamous cell carcinoma, spindle cell carcinoma, metaplastic carcinoma with mesenchymal differentiation, mixed metaplastic carcinoma, and myoepithelial carcinoma 4 .…”

“…The majority of authors agree that MBCs have poorer prognosis as compared to the “classic” TNBC, 2,3,5‐9 although this has not been reported universally 10‐12 …”

Clinicopathological characteristics and prognosis of breast cancer with special histological types: A surveillance, epidemiology, and end results database analysis

“…However, most of them were studies that merely contained a limited cohort adopted in a single medical institution, of which the characteristics of clinical profiles and prognosis could be discordant, or primarily focused on a specific category of breast lesions. Moreover, because of the relatively lower prevalence of special histological breast cancer, presented studies primarily centered on the breast cancer with common histological types, and this group of unusual patients were not systematically investigated on the basis of sufficient clinical data to present the specific biological features and clinical behaviors [ [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] ].…”