Outcome of inflammatory breast cancer in Moroccan patients: clinical, molecular and pathological characteristics of 219 cases from the National Oncology Institute (INO)

Background: Usually misdiagnosed, Inflammatory Breast Cancer (IBC) is the most aggressive form of non-metastatic breast cancer. This orphan disease is more frequent in North Africa. Despite intensive treatment, the survival rate remains very low.

Methods: We have retrospectively studied all breast cancer cases diagnosed at the National Oncology Institute (INO), Rabat between 2005 and 2010. We have collected 219 cases of women with metastatic and non-metastatic IBC. Data have been obtained from patients' personal medical files over a follow-up period of 5 years. We have described IBC's clinicopathological features and analyzed its clinical outcome using SPSS software. HR (hazard Ratio) was calculated using Cox regression analysis.

Results: The frequency of IBC cases is 4.05%. The majority of our patients (65.3%) were under 50 years old. The most prevalent molecular subtype was Luminal A (38.7%) followed by Luminal B HER2+ (27.9%) and Triple negative (21.6%). During the follow-up period, 72 patients (32.9%) had recurrence and 40 patients (18.3%) died. The 3-year OS (Overall Survival) and EFS (Event Free Survival) of non-metastatic patients were 70.4 and 46.5% respectively, while in the metastatic disease, the 3-year OS was only 41.9%. In non-metastatic women, we observed a higher rate of EFS associated to Selective estrogen receptor modulation treatment (p = 0.01), and a lower rate EFS in triple negative breast cancer patients (p = 0.02). In univariate analysis, we found that EFS rate is lower in patients presenting Triple Negative tumors when compared to other molecular subtypes (HR: 3.54; 95%CI: 1.13-11.05; p = 0.02). We also found that Selective estrogen receptor modulation treatment is associated with higher EFS rate (HR: 0.48; 95%CI: 0.07-0.59; p = 0.01).

Conclusions: IBC in Morocco shows similar characteristics to those in North African countries; however, survival rates are still the highest when compared with neighboring countries. Collaborative studies with prospective aspects are warranted to establish the epidemiological profile and understand the high frequencies of IBC in North Africa. More studies on molecular markers are also needed to improve IBC patients' management and eventually their survival rate.