Inflammatory breast cancer outcomes by breast cancer subtype: a population-based study

Aim: To assess the outcomes of breast cancer subtype in inflammatory breast cancer (IBC). Methods: We retrospectively assessed IBC patients from the SEER program. Results: We identified 626 patients, including 230 (36.7%),100 (17.6%), 113 (18.1%), and 173 (27.6%) patients with HoR+/HER2-, HoR+/HER2+, HoR-/HER2+, and HoR-/HER2- subtype disease, respectively. Multivariate analysis demonstrated that, using HoR+/HER2- subtype as reference, patients with HoR+/HER2+ subtype had better breast cancer-specific survival (BCSS) and overall survival (OS), and patients with HoR-/HER2- subtype had worse BCSS and OS, while BCSS and OS were comparable for HoR-/HER2+ subtype. Similar trends were observed in patients who received surgery, radiotherapy, chemotherapy or trimodality therapy. Conclusion: Breast cancer subtype is clinically useful for predicting survival outcome in IBC. The HoR+/HER2- subtype shows poorer survival outcome than HoR+/HER2+ subtype.