Metabolic Syndrome in Focus: Emerging Causes, New Diagnostic Approaches and Criteria, and Long-Term Health Consequences

Metabolic syndrome (MetS) is a complex cluster of metabolic abnormalities, including central obesity, hypertension, dyslipidemia, insulin resistance, and impaired glucose metabolism. Growing evidence indicates that MetS is not only a major risk factor for cardiovascular disease but is also strongly associated with the development and progression of various malignancies. Owing to shared pathophysiological mechanisms, MetS represents an important link between oncologic and cardiovascular diseases. This narrative review aims to provide an integrative assessment of the role of MetS in oncologic and cardiovascular outcomes, with particular emphasis on emerging pathophysiological mechanisms and evolving diagnostic criteria. By synthesizing current evidence, this review addresses existing gaps in the literature regarding the interconnected impact of MetS on long-term health outcomes. A comprehensive literature review was conducted using PubMed, Scopus, and Web of Science, including epidemiological studies, meta-analyses, and clinical studies published between 2000 and 2025 that evaluated associations between MetS, cancer, and cardiovascular disease. Current evidence suggests that MetS significantly increases the risk of both malignancies and cardiovascular disorders. Central mechanisms include chronic low-grade inflammation, insulin resistance with activation of insulin-like growth factor (IGF) signaling pathways, dysregulated lipid metabolism, and endothelial dysfunction. Lifestyle modifications, particularly regular physical activity and antioxidant-rich diets, as well as metabolically targeted pharmacological strategies, may reduce disease incidence and progression. In conclusion, MetS represents a critical, modifiable risk factor linking cancer and cardiovascular disease. Early identification and comprehensive management of MetS may play a pivotal role in improving long-term clinical outcomes.