Lipid Metabolism and Breast Cancer: A Narrative Review of the Prognostic Implications and Chemotherapy-Induced Dyslipidemia.

Lipid metabolism plays a crucial role in breast cancer's progression, treatment response, and prognosis. Alterations in triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) have been implicated in tumor aggressiveness and chemotherapy outcomes. This review examines the relationship between dyslipidemia and breast cancer, with a focus on chemotherapy-induced lipid alterations and their prognostic significance. A comprehensive literature search was conducted in PUBMED, Web of Science, and Google Scholar, identifying 108 unique studies. After applying the inclusion criteria, 21 studies were selected for analysis, covering lipid profile changes before, during, and after chemotherapy, as well as their impact on treatment response and clinical outcomes. Breast cancer patients exhibited lower baseline TC, TG, and LDL-C levels compared to healthy controls; however, chemotherapy significantly increased these markers while decreasing HDL-C from 1.1 to 0.9 mmol/L. The incidence of dyslipidemia rose from 42.98% pre-treatment to 58.28% post-treatment. Chemotherapy-induced lipid alterations were most pronounced in anthracycline- and taxane-based regimens, leading to a 38% increase in TGs and a 23% reduction in HDL-C. While some studies reported that lipid levels normalized post-treatment, others indicated persistent dyslipidemia up to 12 months later. High baseline HDL-C was associated with a better chemotherapy response, whereas elevated TGs and LDL-C correlated with increased tumor aggressiveness, lower pathological complete response rates, and a higher relapse risk. Patients with persistently high post-treatment TGs had significantly worse disease-free survival, with a 30% relapse rate compared to 18% in those with normal TG. Preliminary evidence suggests that lipid-lowering therapies, such as statins, may offer therapeutic benefits in breast cancer by targeting the cholesterol synthesis pathways involved in tumor growth, though further clinical trials are required. Dyslipidemia is a key metabolic factor influencing breast cancer's progression, treatment response, and long-term prognosis. Chemotherapy-induced lipid alterations may persist, increasing cardiovascular risk and potentially affecting therapeutic efficacy. Routine lipid monitoring and metabolic interventions could enhance treatment outcomes and survivorship. Future research should focus on developing lipid-targeted strategies to optimize breast cancer management.