Special Features of Metaplastic Breast Cancer in Tunisian Women

Introduction: Metaplastic breast carcinomas are a rare, heterogeneous group of breast malignancies characterized by an intrinsically aggressive histology and an unfavorable prognosis. Objective: To determine the clinical and pathological characteristics of metaplastic breast cancers in Tunisian patients, and evaluate their impact on its evolution. Methods: A retrospective study of 44 cases of metaplastic cancers archived during a 26-year period in the Cancer Registry of the Tunisian Center. Results: The frequency of metaplastic cancer was 0.97%. Mean age at diagnosis was 55.4 years (range 26 - 84). Average time to diagnosis was 5.5 months. Average clinical tumor size was 4.95 cm (range 1.5 - 15). Axillary ipsilateral adenopathy was present at diagnosis in 45.9%. The clinical stages IIB (31.8%) and IIA (22.7%) predominated. Squamous metaplasia was the most common (68%) followed by the heterologous mesenchymal subtype. Ganglionic invasion was histologically proven in 17 cases, of which 77% had only adenocarcinomatous contingents. Absence of hormone receptor expression and HER2 overexpression predominated. Primary surgery was carried out in 95% of cases. Average follow-up was 40 months (range 2 - 135). Average overall survival (OS) was 74 months, 63% at 5 years and 60% at 10 years. Average progression free survival (PFS) was 29 months (range 3 - 129), 38% at 5 years and 32% at 10 years. Factors significantly influencing OS and PFS were histological lymph node involvement (p = 0.001 and p = 0.002 respectively). Conclusion: Metaplastic breast cancer observed in Tunisian women constitutes a histological type with an unfavorable prognosis whose improvement requires a more adapted therapeutic strategy.