Depression as a Prodromal Symptom of Pancreatic Cancer: A Narrative Review

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, typically diagnosed at an advanced stage. The identification of prodromal symptoms could support earlier detection. Among these, depression is frequently reported, raising the question of whether it may represent not only a reactive response but also a paraneoplastic manifestation. Methods: We conducted a narrative review of clinical, epidemiological and biological literature published between 1988 and 2025. Searches were performed in PubMed/MEDLINE, Scopus, and Web of Science using predefined keywords related to pancreatic cancer, depression, prodromal symptoms, cytokines, and the kynurenine pathway. Eligible studies included clinical cohorts, population-based analyses, biological investigations, and case reports exploring the temporal or mechanistic link between depression and PDAC. Results: A substantial proportion of patients (10–20%) exhibit depressive symptoms in the months preceding the clinical diagnosis of pancreatic cancer. In several cases, depression occurs independent of weight loss and new-onset diabetes. Biological evidence highlights the involvement of pro-inflammatory cytokines (IL-6, IL-1β, TNF-α), NF-κB signaling, and activation of the tryptophan–kynurenine pathway (IDO), suggesting a link between tumor-related processes and mood alterations. These mechanistic findings are actually hypothesis-generating, deriving mainly from small clinical cohorts and preclinical models. Clinically, depression is associated with reduced adherence to treatment, poorer quality of life, and shorter survival. However, no specific depressive phenotype has been identified. Conclusions: Depression may represent a potential prodromal symptom of pancreatic cancer, reflecting systemic biological processes as well as psychological reactions. Its utility as a standalone marker remains limited; future studies should integrate psychiatric, clinical and biological biomarker assessments to enhance early clinical diagnosis.