Pretreatment cardiometabolic risk in newly diagnosed breast cancer: a molecular subtype analysis

Background Breast cancer is the most common female malignancy globally. With improved survival, cardiovascular diseases have become a key morbidity source due to shared cardiometabolic risk factors (e.g., dyslipidemia). While cardiovascular risk varies by breast cancer molecular subtype, baseline pre-treatment cardiovascular comorbidities and lipid abnormalities remain undercharacterized. We aimed to describe their prevalence and subtype-specific patterns in newly diagnosed patients. Methods This single-center retrospective cohort study included 5,246 Chinese women with newly diagnosed breast cancer (2014–2024), with all data collected before anticancer therapy. Patients were stratified into five molecular subtypes. Baseline cardiovascular comorbidities, tumor features, and serum lipids were analyzed using chi-square tests, ANOVA, and multivariable logistic regression. Results Age, cardiovascular comorbidities, electrocardiographic abnormalities and lipid profiles differed significantly across subtypes. Overall dyslipidemia prevalence was 54.1%, highest in Luminal A and lowest in Luminal B (HER2 negative). Intravascular tumor thrombus was independently associated with dyslipidemia in all subtypes, with the strongest association in triple-negative breast cancer. Lymph node metastasis correlated with dyslipidemia only in Luminal B subtypes, and several factors showed subtype-specific associations. Conclusions Dyslipidemia is common at baseline in treatment-naive breast cancer patients and varies by molecular subtype. Tumor-related features, particularly intravascular tumor thrombus, are consistently associated with dyslipidemia. Early lipid screening and cardiovascular risk assessment may optimize cardio-oncology care.