title: Effects of metformin on head and neck cancer: a systematic review.
abstract: Conventional therapeutic approaches for head and neck squamous cell carcinoma (HNSCC) are associated with many adverse effects that reduce quality of life. Therefore, identification of new less cytotoxic treatments is highly important. Metformin, which is commonly used for type 2 diabetes, may reduce cancer risk. A few clinical studies have examined the association between HNSCC and metformin. Therefore, the aim of this systematic review was to synthesize the available literature of the potential effect of metformin on HNSCC. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Studies were gathered by searching PubMed, MEDLINE, EMBASE, LILACS, and the Cochrane database before June 28, 2014, with no time or language restrictions. Studies that evaluated individuals of any age that underwent metformin and had HNSCC and compared with patients without treatment or patients that use other kind of treatment for HNSCC (drugs or radiotherapy) were considered. Selected articles were evaluated according to the Critical Appraisal Skills Programs. Of 313 identified citations, 3 studies met the inclusion criteria and were used for qualitative analysis. These studies demonstrated that individuals taking metformin had decreased rates of locoregional recurrence and metastasis and improved overall survival and disease-free survival rates. Individuals taking metformin had a lower incidence of HNSCC than those not taking metformin. Though there are only a few studies on the topic, currently available evidence suggests an association between HNSCC and metformin use. Metformin reportedly improves the overall survival of HNSCC patients.
authors: Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, Brazil. Electronic address: dani.se.ela@gmail.com.
authors: Daniela Fortunato
authors: DF
authors: Rêgo
authors: Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, Brazil. Electronic address: ludmadeira@hotmail.com.
authors: Ludmila Madeira Cardoso
authors: LM
authors: Pavan
authors: Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, Brazil. Electronic address: silvinhaelias@hotmail.com.
authors: Silvia Taveira
authors: ST
authors: Elias
authors: Department of Dentistry, Federal University of Santa Catarina, Florianópolis, Brazil; Department of Dentistry, University of Alberta, Edmonton, Canada. Electronic address: delucacanto@gmail.com.
authors: Graziela
authors: G
authors: De Luca Canto
authors: Oral Histopathology Laboratory, Health Sciences Faculty, University of Brasília, Brasília, Brazil. Electronic address: elieteneves@unb.br.
authors: Eliete Neves Silva
authors: EN
authors: Guerra
mesh_terms: D006258:Head and Neck Neoplasms / Q000188:drug therapy*; D006801:Humans; D008687:Metformin / Q000627:therapeutic use*
chemical_list: D008687:Metformin
keywords: Evidence-based medicine; Head and neck; Metformin; Squamous cell carcinoma; Systematic review