Elevated Plasma Adrenomedullin Levels in Patients with Unresectable Advanced Gastrointestinal Cancers

Background/Objectives: Adrenomedullin (AM) is a circulating peptide involved in tumor progression, angiogenesis, and fibrosis. However, its clinical utility as a biomarker in gastrointestinal cancers remains unclear. Methods: This single-center prospective observational study included patients with unresectable advanced gastrointestinal cancers (esophageal, gastric, colorectal, biliary tract, and pancreatic cancers) and healthy volunteers. Plasma AM levels were measured before the initiation of systemic chemotherapy in patients with cancer and at the time of enrollment in healthy volunteers. Results: In the unadjusted analyses, plasma mature and total AM levels were significantly higher in the cancer group than in healthy volunteers. Age was significantly associated with both mature and total AM levels, whereas sex did not show a significant association. After adjustment for age, between-group differences in mature and total AM levels were not statistically significant. Among patients with pancreatic cancer, plasma mature and total AM levels were significantly higher in stage IV than in stage III disease. Conclusions: Higher plasma AM levels were observed in the cancer group than in healthy controls in the unadjusted analyses; however, these differences were not statistically significant after adjustment for age. A stage-related difference was observed in pancreatic cancer. These findings should be considered hypothesis-generating and require validation in larger studies with appropriately matched control groups.