Decreased serum HDL at initial diagnosis correlates with worse outcomes for triple-negative breast cancer but not non-TNBCs

Purpose: This study aimed to evaluate the associations between metabolic syndrome (MS) and its components at initial diagnosis and outcomes of breast cancer including triple-negative breast cancer (TNBC) and non-TNBC. Methods: A cohort of 1,391 patients was reviewed between January 2004 and July 2008 (including 394 TNBC and 855 non-TNBC cases). MS and its components including body mass index (BMI), serum high-density lipoprotein (HDL) and triglycerides (TG) and their relationships with clinical outcomes were analyzed and then compared between groups. Results: The incidences of MS and its components including BMI, the levels of HDL and TG were not differently distributed between the 2 groups (all p's >0.05). However, more TNBC than non-TNBC patients presented with hypertension and elevated serum glucose (20.3% vs. 14.9% and 16.0% vs. 10.8%, p = 0.018 and p = 0.012, respectively). TNBC patients had poorer 5-year relapse-free survival (RFS) than non-TNBC patients (72.8% vs. 84.2%, p<0.0001). Only in the TNBC group, patients with low high-density lipoprotein (HDL) demonstrated worse RFS and overall survival (OS; p<0.0001). Multivariate analysis identified that low HDL was an independent worse prognostic factor for both RFS (hazard ratio [HR] = 3.266, 95% confidence interval [95%CI], 2.087-5.112, p<0.0001) and OS (HR = 3.071, 95%CI, 1.732-5.445, p<0.0001) in TNBC patients. Conclusions: Decreased level of HDL may predict worse outcomes both in terms of RFS and OS for TNBC patients but not for non-TNBC patients. Further investigations are warranted to detect the underlying mechanisms.