Clinicopathologic Features and Radiation Therapy for Metaplastic Carcinoma of the Breast

Abstract

Purpose: Metaplastic carcinoma of the breast (MCB) is a rare subtype of breast cancer and characterized by the histologic presence of two or more cellular types of epithelial and mesenchymal components. The purpose of the study is to review the clinicopathologic features and outcomes of MCB treated with radiation therapy (RT) at our institution. Materials and Methods: Patients with MCB of the breast who did not have distant metastasis at diagnosis and received curative-intent RT at our institution were identified. Clinicopathologic features were collected and outcomes were analyzed. We used Kaplan-Meier statistic method to estimate local control, disease-free survival (DFS) and overall survival (OS) in these patients. Results: From 1996 to 2012, twelve MCB patients who met the inclusion criteria were enrolled. Patient age ranged from 29 to 66 years (mean, 48). The median tumor size was 5.3 cm (range, 1.2-19). Nine patients (75%) were nodal negative. Triple negative tumors (ie, ER negative, PR negative and HER2 negative) were found in 9 of 12 patients (75%). Nine patients received mastectomy while 3 patients underwent breast conserving surgery. RT dose ranged from 50-66 Gy (mean, 60). No patient developed local recurrence after RT. The median DFS was 4.2 years. Overall survival was 52.5% at 5 years. Conclusions: Our findings suggest adjuvant RT is a very effective adjuvant treatment on local tumor control for patients with MCB.