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 diagnosis to AHCT, and performance status at AHCT, patients with stage III IBC had higher mortality (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.