The Potential Prognostic Marker TyG Index Predicts Time to Brain Metastasis at HER2 Positive Breast Cancer

BACKGROUND: We aimed to investigate the prognostic significance of insulin resistance (IR) markers fasting triglyceride-glucose (TyG) index and triglyceride high-density lipoprotein cholesterol (TG/HDL-C) ratio in HER2-positive breast cancer (BC) patients with brain metastasis (BM). METHODS: In this single-center study, 120 patients who met the criteria were included. TyG and TG/HDL-C at the time of diagnosis were computed retrospectively. For TyG and TG/HDL-C, the median values of 9.32 and 2.95 were taken as the cut-off, respectively. TyG values <9.32 and <2.95 were considered low, and TG/HDL-C values ≥9.32 and ≥2.95 were considered high. RESULTS: The median overall survival (OS) was 47 months (95% CI: 40.54–53.45). Time to BM was 22 months (95% CI: 17.22–26.73). The median time to BM was 35 months (95% CI: 20.90–49.09) in the low TyG group and 15 months (95% CI: 8.92–21.07) in the high TyG group (p < 0.001). The time to BM was 27 months (95% CI: 20.49–33.50) in the low TG/HDL-C group and 20 months (95% CI: 16.76–23.23) in the high TG/HDL-C group (p=0.084). In the multivariate Cox regression analysis, the TyG index (HR: 20.98, 95% CI: 7.14–61.59, p < 0.001) was an independent risk factor for time to BM. CONCLUSION: These findings suggest that the TyG index could be used as a predictive biomarker at the time of diagnosis for risk of time BM in patients with HER2-positive BC. The TyG index can be used as a standard potential marker with prospective studies confirming these data.