Association of Metformin with Breast Cancer Incidence and Mortality in Patients with Type II Diabetes: A GRADE-Assessed Systematic Review and Meta-analysis
Abstract
Abstract Background: Preclinical data suggest that metformin may reduce breast cancer incidence and improve cancer prognosis. However, the current evidence in observational studies is inconclusive. A systematic review and meta-analysis was conducted to assess the effect of metformin on the incidence of breast cancer and all-cause mortality in patients with type II diabetes (T2D). Methods: A literature search was performed on Medline, EMBASE, and the Cochrane library from inception to November 2016. Outcomes were incidence of breast cancer and all-cause mortality. Risk of bias and overall certainty of evidence was assessed using the Newcastle-Ottawa Scale and Grading of Recommendations Assessment, Development, and Evaluation (GRADE), respectively. Meta-analyses were performed using the most fully adjusted ORs or HRs and 95% confidence intervals (95% CI) as effect measures. Results: A total of 12 observational studies were included for breast cancer incidence and 11 studies for all-cause mortality. No significant association was found between metformin exposure and incidence of breast cancer (OR = 0.93; 95% CI, 0.85–1.03; I2 = 35%). A 45% risk reduction was observed for all-cause mortality (HR = 0.55; 95% CI, 0.44–0.70; I2 = 81%). Presence of publication bias is strongly suspected for both outcomes using Egger's funnel plots. Conclusions: The use of metformin may improve overall survival in patients with T2D and breast cancer. No effect of metformin on the incidence of breast…
How strong is the evidence?
Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid.
Read the paper
Related studies
- Metformin as an adjuvant in breast cancer treatment
- Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?
- Aberrant HSF1 signaling activation underlies metformin amelioration of myocardial infarction in mice
- Metformin induces ZFP36 by mTORC1 inhibition in cervical cancer-derived cell lines
- Protein Interaction Network for Identifying Vascular Response of Metformin (Oral Antidiabetic)
- Preventing Long COVID With Metformin
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.