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.