Survival Outcomes of Metaplastic Breast Cancer XXXX : Results from a US Population-based Analysis.

@entity1 @entity0 @entity66 @entity5 @entity513 @entity5282
BACKGROUND: @entity0 ( @entity0 ) is a rare histologic subtype needing further characterization. The aim of our study was to compare @entity0 to @entity513 ( @entity513 ) of the breast and to identify demographic, clinicopathologic, treatment, and survival differences. METHODS: @entity0 and @entity513 @entity1 were identified using the Surveillance, Epidemiology, and End Results (SEER) public-use data set. @entity66 ( @entity66 ) differences were compared using the Kaplan-Meier method and log-rank tests. Univariate and multivariate Cox proportional hazard models were used to assess factors prognostic for @entity66 . To control for @entity5282 status, a subsequent planned analysis was completed for receptor-negative @entity0 and @entity513 . Lastly, a matched case-control analysis was conducted to minimize potential bias due to baseline demographic, clinical, and pathologic differences. RESULTS: The SEER data set included 1,011 @entity0 and 253,818 @entity513 @entity1 diagnosed from 2001 to 2010. @entity0 @entity1 had larger, higher grade @entity5 , had less frequent axillary nodal involvement, and were more likely to be treated with mastectomy. Five-year @entity66 rates were significantly worse for @entity1 with @entity0 than for @entity513 @entity1 (78 vs. 93  %, p  <  0.0001) and for @entity1 with receptor-negative @entity0 than receptor-negative @entity513 (77 vs. 85  %, p  <  0.0001). The findings were confirmed on matched analysis. Prognostic factors identified on multivariate analyses included age, @entity0 histology, @entity5 grade, T stage, and axillary lymph node involvement. CONCLUSIONS: @entity0 @entity1 have shorter @entity66 than @entity513 @entity1 . Improved clinical and biological understanding of @entity0 may result in more effective therapy and better @entity5 outcomes.
