Predictive significance of surgery-induced lymphopenia on the survival after curative resection for locally advanced gastric cancer: a retrospective cohort analysis

BACKGROUND: Following the establishment of the anti-cancer effect of immune checkpoint inhibitors, lymphopenia has attracted attention as a parameter of preexisting cancer-related immune tolerance. Although the pretreatment absolute lymphocyte count (ALC) has been reported as a prognostic factor in gastric cancer patients, the impact of perioperative changes in the ALC remains unknown. The aim of the present study was to explore the relationship between surgery-induced lymphopenia and outcome. METHODS: Database entries for 584 patients who underwent curative resections for pathological Stage IB-III gastric cancer were reviewed. We retrospectively compared clinicopathological factors including pretreatment ALC (pre-ALC) and ALC at first visit after discharge (post-ALC) with the survival. The low ALC was defined as < 1000/μL. RESULTS: The ALC decreased significantly at 1 and 3 days after surgery and then recovered to the baseline value. A low pre-ALC (p < 0.001) and a low post-ALC (p < 0.001) were both correlated with a poor relapse-free survival (RFS). A multivariate analysis of RFS identified a low post-ALC (hazard ratio 1.875, 95% CI 1.156–3.402, p = 0.01), age, gender, BMI, T disease, N disease, severe vessel invasion, type of gastrectomy and postoperative morbidity as independent factors. The low post-ALC group had a poor RFS among patients with Stage II (p = 0.04) and Stage III (p = 0.04) disease, but not among patients with Stage IB disease (p = 0.13). Consistently, the overall survival (OS) rate was significantly lower among patients with a low post-ALC for all stage (p < 0.001), stage II (p = 0.02) and stage III (p = 0.01) disease, not for stage IB (p = 0.09). A low post-ALC was identified as an independent factor for predicting OS by multivariate analysis (hazard ratio: 2.275, 95% CI 1.373–3.769, p = 0.01). CONCLUSIONS: A decrease in post-ALC was correlated with both of RFS and OS after curative resection in patients with locally advanced gastric cancer. HIGHLIGHTS: Postoperative lymphopenia was a poor prognostic factor for gastric cancer.