Synergistic Benefit of Statin and Metformin in Gastrointestinal Malignancies

Abstract

Objectives: To evaluate whether statin use influences gastrointestinal cancer prognosis in patients with diabetes mellitus (DM). Methods: We reviewed all DM patients diagnosed at Roswell Park Cancer Institute with emergent gastrointestinal malignancy (January 2003 to December 2010) (N = 222). Baseline demographic, clinical history, and cancer outcomes were documented. Overall survival (OS) and disease-free survival (DFS) comparisons across various treatment groups were assessed by Kaplan-Meier and Cox proportional hazards. Results: Use of statin, alone or in combination, was associated with improved OS and DFS (hazard ratio [HR] = 0.65, P = .06; HR = 0.60, P < .02). We report similar OS and DFS advantage among users of mono- or combined metformin therapy (HR = 0.55, P < .01; HR = 0.63, P < .02). Concomitant use of metformin and statin provided a synergistic OS and DFS benefit (HR = 0.42, P < .01; HR = 0.44, P < .01). Despite significant tobacco and alcohol use history, patients with upper gastrointestinal cancers derived enhanced cancer outcomes from this combination (HR = 0.34, P < .01; HR = 0.43, P < .02), while receiving a statin without metformin or metformin without a statin did not provide significant cancer-related benefits. Conclusion: Use of statin and metformin provides a synergistic improvement in gastrointestinal malignancies outcomes.