Prognostic impact of hormone receptor- and HER2-defined subtypes in inflammatory breast cancer treated with high-dose chemotherapy: a retrospective study

Purpose: Studies examining high-dose chemotherapy with autologous hematopoietic stem cell transplantation (HDC-AHSCT) strategies in inflammatory breast cancer (IBC), showed encouraging results in terms of disease-free survival (DFS), and overall survival (OS). The lack of data regarding HER2 status in all of these studies prevented any prognostic analysis involving breast cancer subtypes. Methods: All consecutive female patients treated for IBC with HDC and AHSCT at Institut Paoli-Calmettes between 2003 and 2012 were included. Since 2005, trastuzumab was included in initial treatment. Patient, tumor and treatment characteristics were collected. Patients were categorized in three subtypes based on hormonal receptor (HR) and HER2 status of the primary tumor: Luminal, (HR+/HER2-), HER2 (HER2+, any HR), and triple negative (TN) (HER2- and HR-). The main objective was the analysis of OS according to the IHC subtypes. Results: Sixty-seven patients were included. Eleven patients received trastuzumab. Median follow up was 80.04 months (95% CI 73.2-88.08). Five-year OS and DFS for the whole population patients were 74% (95% CI 61-83) and 65 % (95% CI 52-75), respectively. OS differed across subtypes (p=0.057) : HER2 subgroup appeared to have the best prognosis with a 5-year OS of 89% (95% CI 64-97) compared to 57% (95% CI 33-76) for the TN subgroup (HR 5.38, 95% CI 1.14-25.44; p=0.034). Conclusions: In IBC patients receiving HDC-AHSCT, OS favorably compares with data available in the literature on similar groups of patients. TN patients carried the least favourable OS and HER2 patients, half of them also receiving trastuzumab, had the best outcome. These findings provide additional information and options for patients with IBC and who could potentially benefit of HDC-AHSCT.