Open AccessDurable Response to PD1 Inhibitor Pembrolizumab in a Metastatic, Metaplastic Breast Cancer
Author(s) -
Gorshein Elan,
Matsuda Kant,
Riedlinger Gregory,
Sokol Levi,
Rodriguez-Rodriguez Lorna,
Eladoumikdachi Firas,
Grandhi Miral,
Ganesan Shridar,
Toppmeyer Deborah L.,
Potdevin Lindsay,
Toomey Kathleen,
Hirshfield Kim M.,
Chan Nancy
Publication year - 2021
Publication title -
case reports in oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 19
ISSN - 1662-6575
DOI - 10.1159/000515510
Subject(s) - case report
Metaplastic breast cancer (MBC) is a rare and aggressive subtype of breast cancer. Tumor characteristics typically feature estrogen receptor, progesterone receptor, and HER2-negative, triple-negative breast cancer (TNBC), with a poorer prognosis relative to pure invasive ductal or lobular disease. Resistance to chemotherapy often leads to local recurrence and distant metastasis. Genomic profiling has identified multiple molecular abnormalities that may translate to targetable therapies in MBC. These tumors are known to display higher PD-L1 expressivity than other subtypes of breast cancer, and disease control with pembrolizumab and chemotherapy has been documented. We identify a patient with metastatic, metaplastic TNBC, with mesenchymal components and osseous differentiation, who completed 2 years of pembrolizumab treatment and has remained without evidence of disease after 32 months of observation, while maintaining good quality of life. Future efforts should focus on immunotherapy response with respect to the various subtypes of MBC, and treatment should continue to be incorporated in clinical trials to maximize disease response.