Distinct outcomes in patients with different molecular subtypes of inflammatory breast cancer

OBJECTIVES To determine the outcome of patients with luminal A, luminal B, human epidermal growth factor receptor-2 (HER-2) positive, and triple negative molecular subtypes of inflammatory breast cancer (IBC) using a retrospective analysis. METHODS This study was conducted between February 2004 and February 2010 in 3 different hospitals in China. The clinical outcomes, pathological features, and treatment strategies were analyzed in 67 cases of IBC without distant metastases. A chi-square test and one-way ANOVA were used to assess outcomes between different subtypes. Overall survival (OS) was analyzed using the Kaplan-Meier method and multivariate analysis was conducted using the Cox regression model. RESULTS The 2-year OS rate was 55% for the entire cohort. Median OS time among patients with luminal A was 35 months, luminal B was 30 months, HER-2 positive was 24 months, and triple negative subtypes was 20 months, and were significantly different from each other (p=0.001). Using multivariate analysis, luminal A had 76% (p=0.037), luminal B had 54% (p=0.048), and HER-2 positive subtypes had 47% (p=0.032) decreased risk of death compared with the triple negative subtype.  Furthermore, elevated Ki-67 labeling was associated with increased risk of death, while the surgical treatment significantly improved patient survival. CONCLUSION Breast cancer subtypes are associated with distinct outcomes in IBC patients. Patients that presented with triple negative IBC had poorer outcome than luminal A, luminal B, and HER-2 subtypes. These results indicate that IBC is a heterogeneous disease similar to the conventional breast cancer.