Metaplastic breast carcinoma (MBC) is a rare, heterogeneous breast cancer characterized by admixture of adenocarcinoma with metaplastic elements, low hormone receptor expression, and poor outcomes. The authors retrospectively reviewed the medical records of 47 MBC patients and 1,346 invasive ductal carcinoma (IDC) patients. Two hundred eighteen of the IDC patients were triple-negative (TN-IDC) for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 (ER-/PR-/HER2-). Patients were surgically treated at the Samsung Medical Center between 2005 and 2009. The MBC patients presented with a larger tumor size, lower lymph node involvement, higher histological and nuclear grades, higher triple negativity (ER-/PR-/HER2-) and higher p53, CK5/6, and EGFR expressions compared with those of the IDC group. However, there were no significant differences in clinicopathological characteristics between MBC and TN-IDC. During the follow-up period (median duration of 30.3 months, range 2.6-56.3 months), seven (14.9%) MBC patients, and 98 (7.1%) IDC patients had disease recurrence. The three-year disease-free survival (DFS) rate was 78.1% in the MBC group and 91.1% in IDC group (P < 0.001). The three-year DFS rate was not significantly different between the MBC and TN-IDC groups (78.1 vs. 84.9%, P = 0.114). However, in patients with lymph node metastasis who underwent adjuvant chemotherapy, the three-year DFS rate was 44.4% in the MBC group and 72.5% in the TN-IDC group (P = 0.025). The authors found that MBC had a poorer clinical outcome than did IDC. In breast cancer patients with nodal metastasis, MBC had a poorer prognosis than did TN-IDC, despite adjuvant chemotherapy.

BackgroundResponse to endocrine therapy in breast cancer correlates with estrogen receptor (ER) and progesterone receptor (PR) status. Generally, hormone receptor-positive (HR+) breast cancers have favorable prognosis. In order to understand the exact clinical characteristics and prognosis of single HR-positive breast cancer (ER + PR- tumors and ER-PR+ tumors), we compared these tumors to double HR+ tumors as well as HR- negative tumors (ER-PR-).MethodsWe examined the clinical and biological features of 6,980 women with invasive ductal carcinoma, and these patients were stratified according to ER and PR expression as double HR+ (ER + PR+), single HR+ (ER + PR- and ER-PR+) and double HR-negative (HR-, ER-PR-) tumors.ResultsIn this study, 571 (8.2%) cases were single HR+ tumors, of which 90 (1.3%) were ER-PR+ tumors and 481 (6.9%) were ER + PR- tumors. Our multivariate analysis showed that in patients without HER2 overexpression ER + PR- tumors were associated with an increased risk of recurrence and death compared with ER + PR+ tumors, with a hazard ratio of 2.12 for disease-free survival (DFS) and 4.79 for overall survival (OS). In patients without HER2 overexpression ER-PR+ tumors had increased risk of recurrence and death compared with ER + PR+ tumor, with a hazard ratio of 4.19 for DFS and 7.22 for OS. In contrast, in patients with HER2 overexpression, the difference in survival between single HR+ tumors and double HR+ HR- tumors was not statistically significant. In patients without HER2 overexpression the DFS and OS of ER + PR- and ER-PR+ tumors were not significantly different from those of ER-PR- tumors.ConclusionWe have identified clinically and biologically distinct features of single HR+ tumors (ER–PR+ and ER + PR–) through comparison with both ER + PR+ and ER-PR- tumors. These differences were only significant in HER2- tumors, not in HER2+ tumors. Single HR+ tumors without HER2 overexpression (ER + PR-HER2- or ER-PR + HER2-) were associated with poorer survival than ER + PR + HER2- tumors, and had comparable poor survival to ER-PR-HER2- tumors (triple-negative breast cancer).Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1121-4) contains supplementary material, which is available to authorized users.

PurposeMucinous carcinoma (MC) of the breast is a rare histologic type of mammary neoplasm. The objective of this study was to evaluate the long-term disease-free survival (DFS) and overall survival (OS) of MC.MethodsWe conducted a retrospective analysis of all MC cases reported to a database between 1994 and 2010. Clinicopathological characteristics and survival of 268 MC cases were reviewed and compared with 2,455 invasive ductal carcinoma-not otherwise specified (IDC-NOS) cases.ResultsThe MC cases were of a younger age, involved less lymph nodes, lower stage, more expression of hormonal receptors, and less HER2 overexpression compared to the IDC-NOS cases. The 5-year DFS rate for MC was 95.2% compared to 92.0% for IDC-NOS. The 5-year OS rate for MC was 98.9% compared to 94.9% for IDC-NOS. Multivariate analysis using Cox regression revealed that the mucinous type was a significant prognostic factor for DFS with lower nodal status (N stage) and hormonal therapy. For OS, only N stage was the most significant prognostic factor followed by adjuvant chemotherapy and adjuvant hormonal therapy.ConclusionMC was shown to be associated with a better DFS than IDC-NOS, but it had a similar OS. Nodal status and adjuvant therapy appear to be more significant predictors of prognosis than histologic subtype.