Aim: We aimed to clarify the prognostic significance of HER2 positivity in advanced gastric cancer.
Patients and methods: The cohort included patients with initially metastatic or recurrent gastric cancer treated with first-line modified FOLFOX-6. The HER2 status was analyzed according to modified scoring criteria specific for gastric cancer.
Results: HER2 positivity was shown in 10 out of 114 patients (9.0%). The median time-to-progression (TTP) (4.3 months, 95% confidence interval (CI)=3.6-4.9) and the overall survival (OS) (7.5 months, 95% CI=6.1-8.8) of patients with HER2-positive gastric cancer tended to be shorter than the median TTP (5.9 months, 95% CI=4.5-7.2) and OS (10.8 months, 95% CI=9.2-12.3) of those with HER2-negative gastric cancer (TTP, p=0.177; OS, p=0.068). Particularly in the subgroup of patients without diffuse-type histology, HER2-positive gastric cancer had a worse TTP than those with HER2-negative gastric cancer (p=0.024). In multivariate analysis of this subgroup, HER2 positivity and ECOG performance status of 2 were associated with shorter TTP (hazard ratio (HR)=2.926, p=0.014; HR=2.489, p=0.035, respectively).
Conclusion: HER2-positive gastric cancer seems to confer poorer prognosis, particularly in patients without diffuse-type tumor, treated with modified FOLFOX-6.