Tatiana Natasha Toporcov1, Elisabete Weiderpass2, Suzan Brancher3, Ana Elisa Ribeiro4. 1. Department of Epidemiology, School of Public Health, University of São Paulo, Av. Dr. Arnaldo 715, Cerqueira César, São Paulo, SP, CEP 01246-904, Brazil. 2. International Agency for Research on Cancer (IARC), World Health Organization, Lyon, France. 3. Department of Epidemiology, School of Public Health, University of São Paulo, Av. Dr. Arnaldo 715, Cerqueira César, São Paulo, SP, CEP 01246-904, Brazil. suzanbrancher@usp.br. 4. Department of Dentistry, State University of Ponta Grossa, Ponta Grossa, Brazil.
Abstract
PURPOSE: To assess the effects of metformin use on lung cancer (LC) survival according to summarized results from observational studies (OBs) and randomized clinical trials (RCTs). METHODS: We systematically searched electronic databases and, to our knowledge, for the first time, RCTs were included in a systematic review and meta-analysis about the role of metformin on LC survival. We carried out meta-analyses separately for OBs and RCTs. Analyses for overall survival (OS) concerning OBs were stratified by studies with and without time-dependent approach. Subgroup analyses were adopted for OBs to identify the sources of heterogeneity. Included studies were assessed for quality. RESULTS: We identified ten OBs and four RCTs. For OBs, metformin use was associated with improved OS for LC patients. Only two studies used time-dependent approach in which a higher ratio was found when compared to the non-use of the time-dependent analysis in eight studies. OBs were classified as high quality but the risk of bias was "unclear" in eight OBs due to absence of the time-dependent analysis. For RCTs, metformin use was not beneficial for OS and neither for progression-free survival. Heterogeneous quality was found among RCTs. Sources of bias that could alter significantly the results or raise doubts were identified in RCTs. CONCLUSION: Time-dependent analysis should be considered an appropriate strategy for OBs focused on the metformin use for LC patients' survival, and further studies applying this approach are required. More well-designed RCTs are needed to provide consistent results for the association between metformin use and LC survival.
PURPOSE: To assess the effects of metformin use on lung cancer (LC) survival according to summarized results from observational studies (OBs) and randomized clinical trials (RCTs). METHODS: We systematically searched electronic databases and, to our knowledge, for the first time, RCTs were included in a systematic review and meta-analysis about the role of metformin on LC survival. We carried out meta-analyses separately for OBs and RCTs. Analyses for overall survival (OS) concerning OBs were stratified by studies with and without time-dependent approach. Subgroup analyses were adopted for OBs to identify the sources of heterogeneity. Included studies were assessed for quality. RESULTS: We identified ten OBs and four RCTs. For OBs, metformin use was associated with improved OS for LC patients. Only two studies used time-dependent approach in which a higher ratio was found when compared to the non-use of the time-dependent analysis in eight studies. OBs were classified as high quality but the risk of bias was "unclear" in eight OBs due to absence of the time-dependent analysis. For RCTs, metformin use was not beneficial for OS and neither for progression-free survival. Heterogeneous quality was found among RCTs. Sources of bias that could alter significantly the results or raise doubts were identified in RCTs. CONCLUSION: Time-dependent analysis should be considered an appropriate strategy for OBs focused on the metformin use for LC patients' survival, and further studies applying this approach are required. More well-designed RCTs are needed to provide consistent results for the association between metformin use and LC survival.
Authors: Inaya Ahmed; Adam Ferro; Alan Cohler; John Langenfeld; Sujani G Surakanti; Joseph Aisner; Wei Zou; Bruce G Haffty; Salma K Jabbour Journal: J Thorac Dis Date: 2015-03 Impact factor: 2.895
Authors: Oscar Arrieta; Edgar Varela-Santoyo; Enrique Soto-Perez-de-Celis; Roberto Sánchez-Reyes; Martha De la Torre-Vallejo; Saé Muñiz-Hernández; Andrés F Cardona Journal: BMC Cancer Date: 2016-08-12 Impact factor: 4.430