Effects of metformin on survival outcomes of pancreatic cancer: a meta-analysis

// Yi-Wei Dong 1, * , Yan-Qiang Shi 1, * , Li-Wen He 1 , Xi-Yu Cui 2 and Pei-Zhu Su 2 1 The Second Clinical Medical School of Southern Medical University, Guangzhou 510282, Guangdong, China 2 Department of Gastroenterology, The First People's Hospital of Foshan (Affiliated Foshan Hospital of Sun Yat-sen University), Foshan 528000, Guangdong, China * These authors have contributed equally to this work and should be considered as co-first authors Correspondence to: Xi-Yu Cui, email: cuixiyufoshan@126.com Pei-Zhu Su, email: supeizhu1986@163.com Keywords: pancreatic neoplasms, metformin, prognosis, meta-analysis Received: January 23, 2017 Accepted: April 29, 2017 Published: May 26, 2017 ABSTRACT Background and aim: Recent epidemiological studies indicated that metformin might improve the survival of various cancers. However, its benefit on pancreatic cancer was controversial. Methods: We performed this meta-analysis to investigate the benefit of metformin on pancreatic cancer. A comprehensive literature search was performed through PubMed, Cochrane Library and Embase. Relative risk (RR) and hazard ratio (HR) with 95% confidence interval (CI) were pooled. Results: The meta-analysis of 2 randomized controlled trials including181 pancreatic patients, revealed that metformin use was not associated with an improved overall survival at 6 months (RR=0.90, 95% CI=0.67-1.21), overall survival (HR=1.19, 95% CI=0.86-1.63) and progression-free survival (HR=1.39, 95% CI=0.97-1.99). But the meta-analysis of 8 cohorts, involving 2805 pancreatic patients with diabetes, demonstrated a favorable result with improved overall survival (HR=0.78, 95% CI=0.66-0.92). Conclusions: Observations in the cohort studies supported a favorable role of metformin while the data from randomized controlled trials did not support that. Therefore, more high-quality RCTs are warranted.