Long-Term Outcome of Inflammatory Breast Cancer Compared to Non-Inflammatory Breast Cancer in the Setting of High-Dose Chemotherapy with Autologous Hematopoietic Cell Transplantation

Introduction: Inflammatory breast cancer (IBC) is a rare aggressive form of breast cancer. It is well known that the long-term survival and progression-free survival of IBC are worse than that of non-IBC. We report the long term outcomes of patients with IBC and non-IBC who had undergone high-dose chemotherapy (HDC) with autologous hematopoietic cell transplantation (AHCT). Methods: All 3387 patients with IBC or non-IBC who underwent HDC with AHCT between1990-2002 and registered with CIBMTR were included in this analysis. Transplant-related mortality (TRM), disease relapse/progression, progression-free survival (PFS) and overall survival (OS) were compared between the two cohorts. Multivariate Cox regression model was used to determine the independent impact of stage on outcomes. Results: 527 patients with IBC and 2,860 patients with non-IBC were included; the median age at transplantation (47 vs 46 years old) and median follow-up period in the 2 groups (167 vs 168 months) were similar. The most common conditioning regimen was cyclophosphamide and carboplatin based in both groups (54% in IBC and 50% in non-IBC). AHCT was well tolerated in both groups. TRM was similar in both groups (one year TRM was 2% for IBC and 3% for non-IBC, p= 0.16). The most common cause of death was disease progression or relapse (81% in IBC and 75% in non-IBC). The median survival for both IBC and non-IBC was the same at 40 months. The PFS at 10 years was 27% (95% CI: 23-31%) for IBC and 24% (95% CI: 22-26%) for non-IBC (p= 0.21), and the OS at 10 years was 31% (95% CI: 27-35%) for IBC and 28% (95% CI: 26-30%) for non-IBC (p= 0.16). In univariate analysis, patients with stage III IBC and no active diseases at transplantation had lower PFS and OS than that in non-IBC. In multivariate analysis, controlling for age, disease status at AHCT, hormonal receptor status, time from HR 1.16, 95% CI: 1- 1.34, p=0.0459), worse PFS (HR: 1.17, 95% CI: 1.01-1.36, p= 0.0339) and higher risk of disease relapse/progression (HR: 1.24, 95% CI: 1.06- 1.45, p= 0.0082) as compared to stage III non-IBC. Amongst all patients a higher stage disease was associated with worse PFS, OS and disease relapse/ progression. Conclusions: Long-term outcomes of stage III IBC patients who underwent AHCT were poorer than that in non-IBC patients confirming that the poor prognosis of IBC even in the setting of HDC with AHCT.