Metabolic Syndrome and Pancreatic Cancer: Linking Insulin Resistance, Inflammation, and Carcinogenesis

Metabolic syndrome (MetS) is a composite classification defined by heterogeneous combinations of cardiometabolic abnormalities. Several components have been associated with pancreatic cancer (PC), but studies often conflate long-term metabolic exposure, tumor-related prediagnostic metabolic change, and prognosis after diagnosis. This review critically evaluates these three settings. This narrative review searched PubMed, Scopus, and Web of Science through April 2026, prioritizing meta-analyses, prospective cohorts, Mendelian randomization studies, clinical studies, preclinical mechanistic evidence, and guidelines. Evidence was interpreted with attention to reverse causation, residual confounding, outcome definitions, and validation. Meta-analyses report a 25-34% higher PC risk among individuals with MetS, with a stepwise gradient across the number of metabolic components; hyperglycemia showed the strongest association among individual components (RR 1.55, 95% CI 1.42-1.70). However, MetS represents multiple versions of exposure, and the epidemiological and clinical evidence remains predominantly observational. Proposed mechanisms involving insulin signaling, adipokines, oxidative stress, epigenetic regulation, and the microbiome are largely preclinical and are not pancreas-specific. New-onset diabetes, rising HbA1c, and involuntary weight loss may mark occult pancreatic ductal adenocarcinoma, but available risk-enrichment models and biomarkers are insufficiently validated for routine screening. After diagnosis, metabolic status and body-composition measures have been associated with survival and perioperative outcomes, although confounding and cancer-related cachexia complicate interpretation. MetS is consistently associated with PC risk but is neither a single causal exposure nor an established target for PC prevention. MetS alone does not justify pancreatic imaging or biomarker testing. Lifestyle and pharmacologic treatment should follow established cardiometabolic indications; their effects on PC incidence remain unproven. Priorities include component-specific causal studies and prospective validation of risk-enrichment strategies.