Antihistamines H1 use on survival outcomes in esophageal squamous cell carcinoma patients undergoing concurrent chemoradiotherapy

Esophageal squamous cell carcinoma (ESCC) is a leading cause of cancer-related mortality in Taiwan, with poor survival rates despite standard treatment with concurrent chemoradiotherapy (CCRT). Antihistamines H1 (AH1) may have anticancer effects by reducing allergic reactions, activating mitogen-activated protein kinases, and regulating the immune system. However, the impact of AH1 use during CCRT on survival outcomes in patients with ESCC remains uncertain. A propensity score-matched cohort study was conducted using data from the Taiwan Cancer Registry Database and National Health Insurance Research Database. The primary outcome measures were overall survival and ESCC-specific survival. We analyzed the effects of AH1 use during CCRT on these outcomes using multivariable Cox proportional hazards regression models. The current study involved 981 individuals diagnosed with ESCC who underwent standard CCRT. Out of these, 309 were placed in the non-AH1 group and 672 in the AH1 group. AH1 use during CCRT was found to be associated with improved overall survival (adjusted hazard ratio [HR], 0.52; 95% CI, 0.44-0.60; P<0.0001) and ESCC-specific survival (adjusted HR, 0.47; 95% CI, 0.39-0.56; P<0.0001) compared with nonuse. A dose-response relationship was also observed, with higher cumulative defined daily doses of AH1 associated with lower mortality. The optimal daily intensity dose for AH1 use was found to be 0.84 defined daily doses with the lowest mortality. Our study demonstrates that AH1 use during CCRT for ESCC is associated with improved overall survival and ESCC-specific survival.