Authors: Prof Salma Sultana
Institution: Bangladesh Specialized Hospital
Metaplastic breast cancer (MpBC) is a rare, aggressive, and histologically heterogeneous subtype that has worse survival rates than other triple-negative breast cancers. It accounts for fewer than 1% of invasive breast cancers and is characterized by adenocarcinoma with spindle cells, squamous epithelium, and/or mesenchymal tissue differentiation. The majority of metaplastic breast cancers exhibit the characteristics of triple‐negative breast cancer and have unfavorable prognosis with a lower survival rate. Moreover, among several MpBC subtypes, the squamous subtype was related to better prognosis, and mixed metaplastic carcinomas were associated with worse recurrence‐free survival and breast cancer‐specific survival (BCSS). Currently, the optimal treatment of metaplastic breast cancer remains uncertain.
This study is a single-institution retrospective analysis of 8 patients with MpBC, focused on response to therapies in the context of core biopsy, IHC, Clinical and Pathological staging, histopathology type, chemotherapy regimen and surgery followed by radiation therapy. All the data were obtained from patients’ electronic health records.
Among the MpBC patients, the median age at diagnosis was 49.5 years. 75% with triple-negative disease, 12.5% with squamous cell MpBC,50% spindle cell MpBC, and 12.5% with HER2-low disease along with one case 0f phyllode tumor. 50% received neoadjuvant therapy,25% received adjuvant chemotherapy, 75% underwent MRM breast surgery and 12.5% underwent lumpectomy, 25% received radiation therapy after surgery. Due to the aggressive nature and often larger size of MBC tumors, mastectomy rates tend to be higher than in other types of breast cancer. The majority of metaplastic breast cancers exhibit the characteristics of triple‐negative breast cancer and have unfavorable prognosis with a lower survival rate. Moreover, among several MpBC subtypes, the squamous subtype was related to better prognosis, and mixed metaplastic carcinomas were associated with worse recurrence‐free survival and breast cancer‐specific survival (BCSS).
The NCCN Clinical Practice Guidelines in Oncology for breast cancer do not yet prescribe treatment regimens for MpBC that differ from those for IDC (YAN et al., 2513). Furthermore, standard surgery, radiation, and chemotherapy continue to produce dismal results for MpBC. considering the identification of potential target sites and the rapid advancement of immunological and targeted therapy, molecular and immunocytochemical testing, as well as germline BRCA pathogenic variant testing of breast tumors, should be performed to determine the best treatment strategy to improve the poor prognosis of MpBC patients. In the future, additional well-designed clinical studies will be necessary to investigate effective treatment techniques in MpBC.