Abstract
Trastuzumab has recently been introduced as a treatment for HER2-positive metastatic and/or unresectable gastric cancer (MUGC); however, compared with breast cancer, some issues concerning HER2 and trastuzumab therapy for gastric cancer remain unclear. A 74-year-old woman received trastuzumab-containing chemotherapy for HER2-positive MUGC. She had a marked response to 8 months of chemotherapy, and gastrectomy and hepatic metastasectomy with curative intent were performed. The resected specimen showed complete loss of HER2 positivity in the residual tumor. For MUGC, a change in HER2 status during the course of the disease with or without chemotherapy has rarely been reported. However, in breast cancer, a significant frequency of change in HER2 status during the course of disease has been reported, and reevaluation of HER2 positivity in metastatic/recurrent sites is recommended. The choice of trastuzumab for MUGC is currently based on the HER2 status of the primary tumor at the time of initial diagnosis, without reassessment of HER2 status during the course of disease and/or in metastatic/recurrent sites, on the assumption that HER2 status is stable. However, our case casts doubt on the stability of HER2 in gastric cancer.
Highlights
The primary treatment for patients with metastatic and/or unresectable gastric cancer (MUGC) is systematic chemotherapy
Recent research has shown that adding trastuzumab, a humanized monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER2) protein, to chemotherapy for patients with MUGC with HER2 overexpression and/or gene amplification has a significant superiority to chemotherapy alone in terms of overall survival [4]
We report a case in which chemotherapy containing trastuzumab made it possible to perform curative gastrectomy in a patient with HER2-positive MUGC at initial diagnosis; this case is noteworthy in that HER2 positivity in resected specimens of the residual tumor was completely lost
Summary
The primary treatment for patients with metastatic and/or unresectable gastric cancer (MUGC) is systematic chemotherapy. Recent research has shown that adding trastuzumab, a humanized monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER2) protein, to chemotherapy (fluoropyrimidines and cisplatin) for patients with MUGC with HER2 overexpression and/or gene amplification (the so-called HER2-positive gastric cancer) has a significant superiority to chemotherapy alone in terms of overall survival (median survival 13.8 months with trastuzumab versus 11.1 months with chemotherapy alone) [4]. We report a case in which chemotherapy containing trastuzumab made it possible to perform curative gastrectomy in a patient with HER2-positive MUGC at initial diagnosis; this case is noteworthy in that HER2 positivity in resected specimens of the residual tumor was completely lost. The stability of HER2 status in gastric cancer and provide a literature review of this important topic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
