Comparison of survival outcomes according of patients with metastatic gastric cancer receiving trastuzumab with systemic chemotherapy

Abstract

Purpose: Currently, trastuzumab plus chemotherapy is the standard first-line therapy for human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic gastric cancer (mGC) or esophagogastric junction cancer. However, it is not clear whether the prognosis of HER2-positive mGC treated with trastuzumab plus chemotherapy is better than that of HER2-negative mGC treated with chemotherapy as the first-line therapy.

Methods: We performed a retrospective study comparing the prognosis of mGC according to first-line treatment with trastuzumab plus chemotherapy or chemotherapy only, at the Korea Cancer Center Hospital from 2011 to 2018. The Kaplan-Meier method and Cox proportional hazards model were used for univariate and multivariate survival analyses.

Results: The median overall survival of trastuzumab group was 26.1 months and that of chemotherapy group was 14.8 months (P=0.047). Trastuzumab group had a longer median progression-free survival than chemotherapy group (23.4 vs. 9.2 months, P=0.026). By univariate analysis, sex, age, World Health Organization (WHO) histology, HER2 status, primary tumor site, extent of disease, number of lesions, number of metastatic, measurability of disease, prior gastrectomy, and chemotherapy group are statistically significant. Using multivariate analysis, number of lesions, number of metastatic, prior gastrectomy, and trastuzumab group (hazard ratio, 0.594; 95% confidence interval, 0.384-0.921; P=0.020) were found to be independent prognostic factors of overall survival.

Conclusion: The result suggests prognosis of HER2-positive mGC treated by trastuzumab plus chemotherapy could be better than that of HER2-negative mGC treated by chemotherapy only. Well-designed prospective cohort studies are needed to confirm the results of this study. HER2 testing should be performed routinely in all patients newly diagnosed with mGC.

Keywords: Drug therapy; Esophagogastric junction; Stomach; Survival; Trastuzumab.

Fig. 1

Overall survival and progression-free survival rates among patients following trastuzumab-based and other therapeutic regimens. (A) Median overall survival time of patients who received trastuzumab was 26.1 months and of those who did not receive trastuzumab was 14.8 months. (B) Patients who received trastuzumab had a longer median progression-free survival time than those who did not receive trastuzumab (23.4 months vs. 9.2 months).

Fig. 2

Overall survival and progression-free survival rates among patients in the human epidermal growth factor receptor 2 (HER2)-positive, HER2-negative, and HER2-unknown groups. (A) Median overall survival time in the HER2-positive group was 23.9 months, HER2-negative group was 16.1 months, and HER2-unknown group was 14.6 months. (B) Median progression-free survival time in the HER2-positive group was 21.6 months, HER2-negative group was 10.3 months, and HER2-unknown group was 8.9 months.

Fig. 3

Overall survival and progression-free survival rates among patients in the human epidermal growth factor receptor 2 (HER2)-positive (trastuzumab n=48, other regimens n=11), HER2-negative, and HER2-unknown groups. (A) Median overall survival time in the HER2-positive group was 23.9 months and the HER2-negative/unknown groups was 14.7 months. (B) Median progression-free survival time in the HER2-positive group was 21.6 months and the HER2-negative/unknown group was 9.2 months.

Fig. 4

Overall survival and progression-free survival rates between patients with human epidermal growth factor receptor 2 (HER2)-positive gastric cancer with trastuzumab and those treated with other therapeutics. (A) Median overall survival time of the patients who received trastuzumab was 26.1 months and of those who did not receive trastuzumab was 14.8 months. (B) Patients who received trastuzumab had longer median progression-free survival time than those who did not receive it (23.4 months vs. 9.2 months).