The effect of metformin on mortality following cancer among patients with diabetes
A partir d'une revue systématique de la littérature publiée jusqu'en février 2014 (22 études), cette méta-analyse évalue l'effet de la metformine sur la mortalité des patients diabétiques après le diagnostic d'un cancer
Diabetes may be a risk factor for cancer and is associated with worse cancer outcomes. Metformin may reduce cancer risk, however its effect on mortality following cancer remains less clear. EMBASE and Medline were searched through February 10th, 2014 for studies with reporting an adjusted risk estimate for the effect of metformin therapy on mortality following cancer among diabetic patients. Random-effects models were used to obtain summary hazard ratios (HR) for the association between metformin and all-cause and cancer-specific mortality. Twenty-one observational studies were meta-analyzed in the primary analysis. Metformin was associated with a reduction in all-cause mortality (HR 0.73, 95% CI 0.64-0.83) and cancer-specific mortality (HR 0.74, 95% CI 0.62-0.88). Subgroup analyses by cancer site showed a significant reduction in mortality for colon cancer (4 studies, HR 0.65 (0.56-0.76)) but not for breast and prostate cancers. Observational studies indicate that metformin exposure at cancer diagnosis may be associated with a reduction in mortality. However, these findings need to be interpreted with caution as methodological limitations of individual studies may have introduced biases in these findings. Our results emphasize the need for well-designed studies to further understand the relationship between metformin and survival following cancer.