The prognostic value of metformin for cancer patients with concurrent diabetes: a systematic review and meta-analysis

• Published in: Diabetes, obesity & metabolism Vol. 16; no. 8; pp. 707 - 710
• Main Authors: Zhang, Z.-J., Li, S.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-08-2014; Wiley Subscription Services, Inc
• Subjects: Antidiabetics; Antineoplastic Agents - therapeutic use; Antitumor activity; Breast; Breast cancer; Breast Neoplasms - complications; Breast Neoplasms - diagnosis; Breast Neoplasms - drug therapy; Breast Neoplasms - mortality; cancer; cancer-specific survival; Colorectal Neoplasms - complications; Colorectal Neoplasms - diagnosis; Colorectal Neoplasms - drug therapy; Colorectal Neoplasms - mortality; Diabetes; Diabetes Complications - diagnosis; Diabetes Complications - drug therapy; Diabetes Complications - mortality; Diabetes mellitus; Endometrial cancer; Endometrial Neoplasms - complications; Endometrial Neoplasms - diagnosis; Endometrial Neoplasms - drug therapy; Endometrial Neoplasms - mortality; Endometrium; Epidemiology; Evidence-Based Medicine; Female; Humans; Hypoglycemic Agents - therapeutic use; Male; Medical prognosis; Meta-analysis; Metformin; Metformin - therapeutic use; Mortality; Ovarian cancer; Ovarian Neoplasms - complications; Ovarian Neoplasms - diagnosis; Ovarian Neoplasms - drug therapy; Ovarian Neoplasms - mortality; Ovaries; Prognosis; Survival; Survival Analysis; Uterine cancer; cancer-specific survival; metformin; cancer; prognosis; survival
• ISSN: 1462-8902; 1463-1326
• DOI: 10.1111/dom.12267

Aim
Emerging evidence from epidemiologic studies and basic science suggests a potential antitumour effect of metformin. However, whether metformin improves survival in cancer patients remains inconclusive.
Methods
A literature search was performed using the PubMed, EMbase and SciVerse Scopus databases. Pooled effect estimates were derived using a random‐effects meta‐analysis model.
Results
Of the 28 studies retrieved, the pooled effect estimates showed that metformin was associated with lower risk of all‐cause mortality in cancer patients with concurrent diabetes, particularly for breast [pooled relative risk (RR) 0.70, 95% CI 0.55, 0.88; p = 0.003], colorectal (RR 0.70, 95% CI 0.59, 0.84; p < 0.001), ovarian (RR 0.44, 95% CI 0.30, 0.64; p < 0.001) and endometrial cancer (RR 0.49, 95% CI 0.32, 0.73; p = 0.001). In addition, metformin was associated with lower risks of cancer‐specific mortality.
Conclusions
The findings of this study support the hypothesis that metformin improves the survival for cancer patients with concurrent diabetes, particularly for breast, colorectal, ovarian, and endometrial cancer. Further investigation is warranted.