Clinical outcomes of radical gastrectomy following trastuzumab-based chemotherapy for stage IV HER2-positive gastric or gastroesophageal junction cancer.

ABSTRACT

PURPOSE: Patients who receive trastuzumab (T-mab) plus chemotherapy for stage IV HER2-positive gastric or gastroesophageal junction cancer sometimes respond remarkably well and can undergo radical surgery. However, the clinical outcomes of preoperative T-mab combined chemotherapy with radical gastrectomy remain unclear. We conducted this study to investigate the clinical outcomes of this multimodal treatment. METHODS: From among a total of 199 patients who received T-mab-based chemotherapy for stage IV HER2-positive gastric or gastroesophageal junction cancer between 2011 and 2018, the subjects of this retrospective analysis were 20 patients who subsequently underwent radical gastrectomy. RESULTS: Seven patients had gastroesophageal junction cancer and 13 had gastric cancer. Eleven patients had unresectable stage IV cancer and 9 had resectable metastatic disease. Chemotherapy regimens included capecitabine, cisplatin + T-mab (11 patients), and S-1, oxaliplatin + T-mab (nine patients). The median number of chemotherapy cycles before surgery was three (range, 2-62). During preoperative chemotherapy, grade 3/4 adverse events developed in six patients. None suffered grade ≥ 3b postoperative complications. The 3-year relapse-free survival (RFS) and overall survival (OS) rates were 58.9% and 89.5%, respectively. CONCLUSION: Combined preoperative T-mab-based chemotherapy and surgery appears to be safe and effective for stage IV HER2-positive gastric or gastroesophageal junction cancer, with a clinically meaningful impact on RFS and OS.