Trends in Chemotherapy Patterns and Survival of Patients with Advanced Gastric Cancer over a 16-Year Period: Impact of Anti-HER2-Targeted Agent in the Real-World Setting.

ABSTRACT

PURPOSE: This study aimed to evaluate the survivals of patients with metastatic or recurrent gastric cancer (MRGC) over a period of 16 years and to investigate the recent changes in chemotherapy patterns. MATERIALS AND METHODS: A total of 5,384 patients who received chemotherapy for MRGC between 2000 and 2015 were analyzed. The analysis focused on a comparison of the first-line chemotherapy between four periods 2000-2003 (period 1), 2004-2007 (period 2), 2008-2011 (period 3), and 2012-2015 (period 4). RESULTS: There were 880 patients (16%) in period 1, 1,573 (29%) in period 2, 1,435 (27%) in period 3, and 1,496 (28%) in period 4. Cytotoxic doublet-based therapy was the most commonly used (78%) first-line chemotherapy, and the combination of trastuzumab and doublet chemotherapy was provided to 288 patients. The overall survival (OS) rates at 12 and 24 months were steadily improved as follows 39.2% and 14.6% in period 1, 43.5% and 17.6% in period 2, 50.3% and 20.6% in period 3, and 51.7% and 24.1% in period 4, respectively (p < 0.001). Among the patients who received the doublet-based chemotherapy, the median OS of those who received trastuzumab was 18.0 months (95% confidence interval [CI], 15.5 to 20.6), while that of those who received other doublet therapies was 11.2 months (95% CI, 10.8 to 11.6). CONCLUSION: The OS was improved over time with advancements in chemotherapy, particularly the introduction of the anti-HER2-targeted agent, which contributed to the increase in the number of long-term survivors and established the superiority of OS for the treatment of MRGC.