Clinicopathological characteristics and prognosis of mucinous breast carcinoma

Background: Mucinous breast carcinoma (MuBC) is a rare special type of breast cancer, which can be classified into pure mucinous breast carcinoma (PMuBC) and mixed mucinous breast carcinoma (MMuBC) types based on the proportion of mucinous components. This study aims to compare the clinicopathological characteristics and long-term prognosis between PMuBC and MMuBC, and to analyze prognostic factors to provide evidence for personalized treatment.

Methods: Clinical and pathological data were retrospectively collected from 341 patients diagnosed with MuBC at Sun Yat-sen Memorial Hospital, Sun Yat-sen University, from January 2000 to April 2025, including 239 cases (70.1%) of PMuBC and 102 cases (29.9%) of MMuBC. Clinicopathological features were compared between the two groups. Cox proportional hazards regression model was used to determine the prognostic factors of MuBC.Kaplan-Meier and log-rank tests were used for survival analysis.

Results: Compared to the PMuBC group, patients in the MMuBC group exhibited a higher HER-2 positivity rate (11.76% vs. 3.35%, P=0.009), more advanced clinical stage at diagnosis (stage III-IV: 15.64% vs. 3.7%, P<0.001), and higher rates of receiving chemotherapy (61.76% vs. 39.75%, P=0.001) and breast-conserving surgery (50.98% vs. 34.31%, P=0.004). The 5-year disease-free survival (DFS) rate was 97.1% in both groups (P=0.237). However, the 10-year overall survival (OS) rate was significantly better in the PMuBC group than in the MMuBC group (96.7% vs. 86.3%, P<0.001). Multivariate analysis identified pathological type as an independent prognostic factor for OS, with MMuBC patients having nearly five times the risk of death compared to PMuBC patients (HR=4.937, 95%CI 2.122-11.484, P<0.001). Additionally, TNM stage (stage III, IV) and age (>45 years) were also independent adverse prognostic factors for OS (P<0.05).

Conclusion: PMuBC and MMuBC represent two distinct disease entities with significant differences in clinicopathological features and prognosis. MMuBC exhibits stronger biological aggressiveness and a significantly worse long-term survival outcome compared to PMuBC, and should be considered a high-risk population requiring more aggressive treatment and close follow-up. Accurate distinction of pathological types is crucial for prognosis assessment and treatment decision-making.

Dr. Jane Doe is an epidemiologist specializing in infectious disease research and outbreak response. She holds a PhD in Epidemiology from Harvard University and an MPH from Johns Hopkins University. Dr. Doe has worked with WHO and CDC on global health initiatives and has published extensively on zoonotic diseases. She is currently the Director of the Global Infectious Disease Program at the University of California, San Francisco