title: The risk of cancer development in systemic sclerosis: a meta-analysis.
abstract: OBJECTIVE
  Systemic sclerosis is a multi-system disorder of connective tissue characterized by Raynaud's phenomenon and fibrosis of various organs. The risk of development of cancer in systemic sclerosis (SSc) has been extensively investigated with inconclusive results. To shed some light on the controversy, we conducted a meta-analysis of all published articles linking SSc to the risk of cancer development.
  
  
  METHODS
  Relevant electronic databases were searched for English-language studies characterizing the association of cancers in patients with SSc. Standardized incidence rate (SIR) with its 95% confidence interval (CI) of each study was combined using a fixed/random effect model.
  
  
  RESULTS
  A total of seven papers including 7183 SSc patients were identified, of which 7 reported the SIR for lung cancer, 4 for non-Hodgkin's lymphoma (NHL) and 4 for hematopoietic cancer and 7 for breast cancer. Compared with the general population, the combined SIR was 3.14 (95% CI: 2.02-4.89), 2.68 (95% CI: 1.58-4.56), 2.57 (95% CI: 1.79-3.68) and 1.09 (95% CI: 0.86-1.38), respectively. Significant heterogeneity was observed in lung cancer group (Q=26.13, P<0.001, I(2)=77%). Potential publication bias was absent.
  
  
  CONCLUSIONS
  This present meta-analysis demonstrated an increased risk of lung, non-Hodgkin's lymphoma and hematopoietic cancers among patients with SSc, but not for breast cancer. However, some of the available data were several decades old, and future studies taking new treatment strategies into account are required.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China.
authors.forename: Jun-Qing
authors.initials: JQ
authors.lastname: Zhang
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Wan
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Peng
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Yan
authors.forename: Bao-Zhu
authors.initials: BZ
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Mei
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Yao
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Yang
authors.forename: Jin-Hui
authors.initials: JH
authors.lastname: Tao
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
mesh_terms: D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000453:epidemiology*; D012595:Scleroderma, Systemic / Q000453:epidemiology*
keywords: Cancer; Meta-analysis; Standardized incidence rate; Systemic sclerosis