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

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.