Molecular and epidemiological characteristics of inflammatory breast cancer in Algerian patients

Abstract

Inflammatory breast cancer (IBC) shows a high incidence in Tunisia and Egypt but epidemiological and molecular characteristics have not been described in Algeria. We compared 117 IBC and 59 non-IBC locally advanced breast cancers (LABC), for estrogen and progesterone receptors, HER2, and EGFR protein expression by immunohistochemistry, and HER2 gene amplification by chromogenic in situ hybridization. Demographic, clinico-pathological, and molecular variables were compared with chi-square and Fisher's exact tests to test for significance (P < 0.05, two-tailed). Overall survival (OS) and disease-free survival (DFS) were plotted using Kaplan-Meier curves and compared using the log-rank test. Tumor emboli were detected in 77% of IBC. Palpable masses were found in all LABC but only in 32% of IBC (P < 0.001). Recurrences were higher in LABC than in IBC (48 vs. 35%; P = 0.14) but OS was worse in IBC (68 vs. 71%; P = 0.06). There were no significant differences between IBC and LABC by demographics or by clinico-pathological parameters. The majority of IBC and LABC tumors were luminal A (62 and 64%), followed by basal (~18%, each), triple negative (~18%, each), and HER2+ (~10%, each) subtypes. In multivariate analyses, grade was associated with worse OS (P = 0.04), and DFS (P < 0.001) in IBC; chemo- and radio-therapy were associated with improved OS and DFS, respectively (P < 0.05 for each) in LABC. In conclusion, IBC in Algeria shows similar characteristics to IBC described for Egypt and Tunisia with subtle molecular differences. Current therapeutic treatments were not very effective in this population and new approaches are much needed.