Efficacy of trastuzumab and potential risk factors on survival in patients with HER2-positive metastatic gastric cancer

Gastric cancer has a poor prognosis despite available treatments. Inclusive studies are still needed with real-life data. Our research retrospectively evaluated the efficacy of trastuzumab and potential risk factors on survival in patients with HER2-positive metastatic gastric cancer who received trastuzumab-based chemotherapy as first-line therapy. In total, 138 patients were included in this study. Clinical response to trastuzumab-based chemotherapy was obtained in 79% of the patients. We also divided the patients who had a clinical response into two groups according to whether they received maintenance therapy. In the present study, trastuzumab administration had compatible survival outcomes with recent studies. Continuation of trastuzumab maintenance treatment provided a survival advantage in patients with clinical response. We suppose that maintenance trastuzumab may be recommended in patients with clinical responses to the first-line treatment. Furthermore, Eastern Cooperative Oncology Group Performance Status 2, grade 3 and having more than four metastatic lesions were determined as risk factors for death. Therefore, although we recommend maintenance of trastuzumab in patients with clinical response, those with identified risk factors may not benefit from treatment. Aim: To evaluate the efficacy of trastuzumab and potential risk factors on survival in patients with HER2-positive metastatic gastric cancer. Methods: We retrospectively included 138 patients who were given trastuzumab-based chemotherapy as first-line treatment and analyzed the relationship between clinical response rates and maintenance treatment status and survival outcomes. Results: In the whole group, the median progression-free survival and overall survival were 10.2 and 16 months, respectively. Clinical response was obtained in 79% of patients. The median overall survival was 16.9 months in follow-up group and 19.0 months in the maintenance group in patients with clinical response. Continuation of maintenance trastuzumab created a significant survival advantage (p = 0.021). Eastern Cooperative Oncology Group performance status 2 (hazard ratio [HR]: 2.02), grade 3 (HR: 1.78) and more than four metastatic lesions (HR: 1.67) were determined as risk factors for death. Conclusion: We recommend the continuation of maintenance trastuzumab in patients with clinical response, but those with identified risk factors may not benefit from treatment because life expectancy may be low.