Abstract
PurposeMetaplastic breast carcinoma (MBC) is a rare type of breast cancer that accounts for 0.2-1% of all breast cancers. To date, there are only few institutional studies comparing survival rates between different subtypes. In this retrospective cohort study, we aim to evaluate factors effecting survival rates of different subtypes of MBC.MethodsThis retrospective cohort study observed 118 non-metastatic MBC patients record extracted from 15,244 breast cancer cases between December 2000 and December 2020. In order to analyse factors effecting survival rates of mesenchymal subtype of MBC, all cases are classified as mesenchymal (n=45) and other (n=48). Twenty-five cases that could not be sub-classified due to the missing data. Univariate and multivariate logistic regression analysis were performed to define factors associated with survival rates.ResultsOf the 15,244 cases, 118 (0.8%) were non-metastatic MBC. 105 were triple negative and 12 were non-luminal HER2. There was no significant difference between mesenchymal and other subgroups for age, median tumour size, AJCC staging, and type of surgery. Of the five local recurrences with known subgroup, four of them had mesenchymal subtype. It is demonstrated that mesenchymal subtype was significantly associated with worse 5-year disease-free survival and disease specific survival (HR: 2.35 [1.01-5.48], p=0.049 and HR: 3.16 [1.06-9.47], p=0.040 with 95% CI respectively).ConclusionThis study is one of the few studies presenting the survival outcomes of subtypes of MBCs. Nonetheless, it is the only study demonstrating that mesenchymal subtype had worse survival outcomes. Further studies are needed to determine the outcome of different subtypes of MBCs.
Cyclophosphamide- metabolizing enzyme polymorphisms and survival outcomes after adjuvant chemotherapy for node-positive breast cancer: a retrospective cohort study