Clinicopathological and Radiological Features with Long Term Follow Up of Metaplastic Carcinoma Breast in India

OBJECTIVE: Metaplastic breast carcinoma (MBC) is a heterogeneous group of invasive carcinomas with squamous and/or mesenchymal differentiation. Because of their rare occurrence, the information regarding the clinical behaviour of metaplastic carcinomas is limited. The purpose of our study was to delineate the clinicopathological and radiological features, treatment outcomes, prognostic factors, and survival of patients with MBC. METHODS: Ambispective observational study with prospective recruitment was done from 1(st) January 2019 to 31(st) August 2020. Retrospective data included between 1(st) January 2009 and 31(st) December 2018. In the retrospective group surgical database of our department was searched and those with MBC diagnosis on post-operative histopathology recruited. In prospective group patients with MBC on core biopsy were followed and those operated were included. The patients followed up at our breast cancer clinic (BCC) and their demographic, clinical, pathological radiological and treatment details noted. RESULTS: Forty patients formed the study population. The mean age of the patents was 42 years. Ipsilateral axillary lymph node metastasis was present in 22.5%. The pathological median tumor size was 5.4 (range 2.1 to 22 cm). The most common differentiation was cartilaginous (35%) followed by squamous (32.5%). The most common mammographic grading was BIRADS 4 (Breast Imaging Reporting and Data system). Magnetic resonance imaging was T2 hyperintense with peripheral rim enhancement and restriction on DWI. The median overall (OS) and disease-free survival (DFS) was 42 and 40 months, respectively. Fifteen patients (37.5%) had disease related mortality. A subgroup analysis revealed that, type of differentiation, histopathology and tumor size > 5cm affected both OS and DFS significantly. CONCLUSION: Metaplastic breast cancer in our setup presents in young patients with aggressive large tumors at a higher stage and diverse histopathology and with comparable overall and disease-free survival. The histological subtype, tumor differentiation and tumor size are prognostic factors.