Abstract 5695: Use of certain antihistamines among breast cancer patients confers survival benefit

Abstract

Abstract H1-antihistamines have not been widely studied in relation to cancer therapy, despite being among the most common medications used globally, and having become increasingly sophisticated, cheap and safe. In a nation-wide study of the entire Swedish population using the Drug Prescription Registry, Cancer Registry and Cause of Death Registry- the first of its kind - we investigated the effects of the six major antihistamines (cetirizine, clemastine, desloratadine, ebastine, fexofenadine and loratadine) on breast cancer-related (as well as all-cause) mortality. Our study includes 61,627 Swedish women with breast cancer diagnosed between July 1st 2005 and December 31st 2013. 14,711 used at least one of the six major antihistamines. Both peri- and post-diagnostic antihistamine use was analyzed, as well as the use among different subgroups of patients, divided according to age, stage and estrogen receptor status, was analyzed. Here, we show a consistently beneficial effect of desloratadine and ebastine use on breast cancer survival (in the peri-diagnostic analysis, for desloratadine, HR=0.79 [95% CI 0.63-0.99], P=0.044; and for ebastine users, HR=0.57 [95% CI 0.32-1.03], P=0.064; relative to non-users) and a consistently negative effect on breast cancer survival of clemastine use (in the peri-diagnostic analysis, HR=1.24 [95% CI 1.05-1.47], P=0.013; relative to non-users). Loratadine use is associated with better survival in the peri-diagnostic analysis (HR=0.78 [95% CI 0.63-0.97], P=0.022) relative to non-use. No significant effects were seen for cetirizine use or fexofenadine use. Post diagnostic use. A woman with breast cancer using desloratadine will lower her relative risk of breast cancer-related death with 15% after one year's use and 17% after two years' use (both risks relative to a woman of the same age and the same tumor status). Conclusion. Use of desloratadine and ebastine may may significantly improve survival in breast cancer with few side effects. Citation Format: Hakan L. Olsson. Use of certain antihistamines among breast cancer patients confers survival benefit [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5695.