Abstract
Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive and lethal human malignancies, with five-year survival rates showing only marginal improvement despite decades of intensive research. Its dismal prognosis reflects a combination of intrinsic biological aggressiveness, late clinical presentation, and marked resistance to standard therapies, underscoring the urgent need for innovative diagnostic and therapeutic approaches. Growing evidence indicates that the microbiome is a modifiable factor influencing the onset, progression, and treatment response of PDAC. Microbial communities originating from the gut, oral cavity, and even the tumor microenvironment can shape carcinogenic pathways, modulate immune activity, and alter the efficacy of chemotherapy and immunotherapy. In addition to bacteria, fungal and viral populations are emerging as relevant contributors within this complex ecosystem. This review provides a comprehensive overview of the current mechanistic and translational evidence linking the microbiome to PDAC biology and therapy. It further explores microbiota-targeted interventions-such as probiotics, postbiotics, engineered bacterial strains, bacteriophages, oncolytic viruses, and fecal microbiota transplantation-as promising adjuncts to conventional treatments. A deeper understanding of host-microbiome interactions could yield novel biomarkers and open innovative avenues for precision medicine in PDAC, ultimately improving patient outcomes and reshaping therapeutic paradigms. Integrating microbiome-based strategies into PDAC management may thus represent a crucial step toward more effective and personalized oncologic care.