Evidence map›Paper›PMID 24985407›Full record

SynthesisCancer prevention research (Philadelphia, Pa.)2014

Metformin and cancer risk and mortality: a systematic review and meta-analysis taking into account biases and confounders.

Sara Gandini, Matteo Puntoni, Brandy M Heckman-Stoddard, Barbara K Dunn, Leslie Ford, Andrea DeCensi, Eva Szabo

Open access · bronzeAbstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Cancer prevention research (Philadelphia, Pa.), 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 224 papers, 15 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
224citing papers in PubMed, 15 pooled it
17.2field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

224 citing papers in PubMed, 15 syntheses or guidelines pooled it, 451 citations in OpenAlex.

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  4. Association of metformin use and cancer incidence: a systematic review and meta-analysis.Journal of the National Cancer Institute · 2024 · on this map
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  14. Metformin as an adjuvant treatment for cancer: a systematic review and meta-analysis.Annals of oncology : official journal of the European Society for Medical Oncology · 2016
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164 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors at 2 institutions in 2 countries.

Sara GandiniDivision of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
Matteo PuntoniClinical Trials Office, Office of the Scientific Director, E.O. Ospedali Galliera, Genoa, Italy.
Brandy M Heckman-StoddardBreast and Gynecologic Cancer Research Group, Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland.
Barbara K DunnChemopreventive Agent Development Research Group, Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland.
Leslie FordDivision of Cancer Prevention, National Cancer Institute, Bethesda, Maryland.
Andrea DeCensiDivision of Medical Oncology, E.O. Ospedali Galliera, Genoa, Italy.
Eva SzaboLung and Upper Aerodigestive Cancer Research Group, Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland. szaboe@mail.nih.gov.
Ente Ospedaliero Ospedali Galliera · ITNational Cancer Institute · US

Funding

Intramural NIH HHS Z99 CA999999
6 · The paper itself

Abstract

Previous meta-analyses have shown that the antidiabetic agent metformin is associated with reduced cancer incidence and mortality. However, this effect has not been consistently demonstrated in animal models and recent epidemiologic studies. We performed a meta-analysis with a focus on confounders and biases, including body mass index (BMI), study type, and time-related biases. We identified 71 articles published between January 1, 1966, and May 31, 2013, through Pubmed, ISI Web of Science (Science Citation Index Expanded), Embase, and the Cochrane library that were related to metformin and cancer incidence or mortality. Study characteristics and outcomes were abstracted for each study that met inclusion criteria. We included estimates from 47 independent studies and 65,540 cancer cases in patients with diabetes. Overall cancer incidence was reduced by 31% [summary relative risk (SRR), 0.69; 95% confidence interval (CI), 0.52-0.90], although between-study heterogeneity was considerable (I(2) = 88%). Cancer mortality was reduced by 34% (SRR, 0.66; 95% CI, 0.54-0.81; I(2) = 21%). BMI-adjusted studies and studies without time-related biases also showed significant reduction in cancer incidence (SRR, 0.82; 95% CI, 0.70-0.96 with I(2) = 76% and SRR, 0.90; 95% CI, 0.89-0.91 with I(2) = 56%, respectively), albeit with lesser magnitude (18% and 10% reduction, respectively). However, studies of cancer mortality and individual organ sites did not consistently show significant reductions across all types of analyses. Although these associations may not be causal, our results show that metformin may reduce cancer incidence and mortality in patients with diabetes However, the reduction seems to be of modest magnitude and not affecting all populations equally. Clinical trials are needed to determine if these observations apply to nondiabetic populations and to specific organ sites.

Indexed as

Diabetes Mellitus, Type 2HumansHypoglycemic AgentsMetforminNeoplasmsRiskHypoglycemic AgentsMetformin

Identifiers

PMID24985407
PMCPMC4154969
OpenAlexW1976655891

What Socratic holds

Texttitle and abstract
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.