Prognostic value of natural killer cell activity for patients with HER2 + advanced gastric cancer treated with first-line fluoropyrimidine–platinum doublet plus trastuzumab

Background We aimed to evaluate the prognostic value of natural killer (NK) cell activity for patients with HER2 + advanced gastric cancer (AGC) treated with first-line fluoropyrimidine–platinum doublet plus trastuzumab. Methods Forty-one patients with HER2 + AGC who received fluoropyrimidine–platinum doublet plus trastuzumab as first-line treatment were prospectively enrolled. NK cell activity was evaluated using the NK Vue®. Results The median age was 63.5 years, and 31 patients (75.6%) were male. Patients with low baseline NK cell activity (≤ median, n = 21) were associated worse progression-free survival (PFS) and overall survival (OS) compared with patients with high baseline NK cell activity (> median, n = 20) with a median PFS of 4.21 vs. 9.53 months ( P