title: Correlations Between Serum IL-6 Levels and Radiation Pneumonitis in Lung Cancer Patients: A Meta-Analysis.
abstract: OBJECTIVE
  Diagnostic significance of interleukin 6 (IL-6) for lung cancer patients with radiation pneumonitis (RP) was examined within various studies, but yielded conflicting results. Thus, this meta-analysis was performed to demonstrate correlations between serum IL-6 levels and RP in lung cancer patients.
  
  
  METHODS
  Electronic databases updated to March 2014 were searched to find relevant studies. Relevant literatures were searched under the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, CBM and CNKI databases. STATA statistical software (Version 12.0, Stata Corporation, and College Station, TX) Standardized mean difference (SMD), and its corresponding 95% confidence intervals (CIs) were used for this meta-analysis. In addition, nine cohort studies met the inclusion criteria and involved a total of 137 RP patients and 295 non-RP patients.
  
  
  RESULTS
  The results of combined SMD suggested that serum IL-6 levels in RP patients was significantly higher than in non-RP patients before radiotherapy. While, there was a significant difference in serum IL-6 levels of RP patients between before and after radiotherapy, we observed no difference in serum IL-6 levels between RP patients and non-RP patients after radiotherapy. Ethnicity-stratified analyses indicated that increased serum IL-6 levels were related to the risk of RP in lung cancer patients among Caucasians, but not detected among Asians (all P > 0.05).
  
  
  CONCLUSIONS
  The main finding of our meta-analysis reveals that increased serum IL-6 levels may contribute to the incidence of RP in lung cancer patients, especially among Caucasians.
authors.affiliation: Department of Oncology, The First Hospital of Qinhuangdao, Qinhuangdao, P.R. China.
authors.forename: Zhan-Zhao
authors.initials: ZZ
authors.lastname: Fu
authors.affiliation: Department of Bioengineering, Yanshan University, Qinhuangdao, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Oncology, The First Hospital of Qinhuangdao, Qinhuangdao, P.R. China.
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Cao
authors.affiliation: MRI Room, The First Hospital of Qinhuangdao, Qinhuangdao, P.R. China.
authors.forename: Yan-Sheng
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Department of Chemical Engineering, Yanshan University, Qinhuangdao, P.R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Yanshan University, Qinhuangdao, P.R. China.
authors.forename: Bao-Hong
authors.initials: BH
authors.lastname: Fu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D018740:Genetic Heterogeneity; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008175:Lung Neoplasms / Q000097:blood* / Q000150:complications* / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D017594:Publication Bias; D017564:Radiation Pneumonitis / Q000097:blood* / Q000150:complications*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6
keywords: interleukin-6; lung cancer; meta-analysis; radiation pneumonitis; radiotherapy