Clinicopathological characteristics of mucinous breast cancer: a retrospective analysis of a 6-years study from national cancer center in Vietnam

To evaluate clinicopathological features in women with mucinous breast cancer (MBC), distinguishing between pure (PMC) and mixed (MMC) subtype. A retrospective analysis of all 358 women with MBC treated at Vietnam National Cancer hospital from June 2015 to December 2020. PMC was defined by ≥ 90% mucinous components. We identified 358 women with MBC (245 PMC and 113 MMC) representing 2.7% of all 13,254 BC patients. The proportions of stage I, II, III and IV were 34.9%, 50.8%, 10.4% and 3.9% respectively. The rate of HER2 overexpression was 12%, and only 1.4% of patients was treated with anti-HER2. 193 patients (53.9%) had chemotherapy, including 55 patients (15.4%) treated in the neoadjuvant setting. Only 3 patients (5.5%) achieved pCR. PMC patients were older (54.4 ± 13.3 vs 51.1 ± 13.1 years), had lower Ki67 expression, lower incidence of nodal metastasis (N +) (p values