title: The risk of cancer in patients with connective tissue diseases but without dermatomyositis or polymyositis: A multicenter cohort study conducted over 15 years in China.
abstract: To investigate the relative risk of cancer in Chinese patients with connective tissue diseases (CTD) associated with and without dermatomyositis or polymyositis.
  
  
  
  A retrospective, multicenter cohort study investigated 32,380 CTD patients (2334 diagnosed with dermatomyositis or polymyositis) without a history of malignancies treated from January 1, 1997, to December 31, 2011. Standardized incidence ratios (SIR) of cancers determined the incidence of malignancies during follow-up. The data was compared with the cancer morbidity of the general population from the Chinese Cancer Registry Annual Report of National Central Cancer Registry.
  
  
  
  A total of 113 patients (348.98 per 100,000) developed cancer during follow-up, 75 (249.62 per 100,000) were patients with CTD without dermatomyositis or polymyositis. The risk of cancer among patients with CTD was increased (SIR=1.45, 95% confidence interval [CI] 1.22-1.71), and this risk increased with age (<40 years: SIR=1.00 [95%CI 0.45-2.21]; 41-60 years: SIR=1.53 [95%CI 1.17-2.00]; and >60 years SIR=2.34 (95%CI 0.93-2.77]) and the time of follow-up (<1year: SIR=1.22 [95%CI 0.88-1.70]; 1-5 years: SIR=1.14 [95%CI 0.79-1.65]; and 6-10 years SIR=1.70 [95%CI 1.34-2.85]), but was similar between genders (male SIR=1.60 [95%CI 1.10-2.31] and female SIR=1.25 [95%CI 1.01-1.55]). The cancer risk among CTD patients without dermatomyositis or polymyositis was not affected (SIR=0.93, 95%CI 0.75-1.16), regardless of gender, age, or follow-up.
  
  
  
  The cancer risk for patients with CTD without dermatomyositis or polymyositis was not increased or decreased, but it was increased when patients with dermatomyositis or polymyositis were included.
authors.affiliation: Department of Hematology, Zaozhuang Municipal Hospital, Zaozhuang, Shandong Province, China. Electronic address: xuwei1621@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Laboratory Medicine, Affiliated Hospital of Jining Medical College, Jining, Shandong Province, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Dermatology, Affiliated Heping Hospital of Changzhi Medical College, Changzhi, Shanxi Province, China; Affiliated Hospital of Guiyang Medical University, Guiyang, Guizhou Province, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Hematology, Zaozhuang Municipal Hospital, Zaozhuang, Shandong Province, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Binzhou City Center Hospital, Binzhou, Shandong Province, China.
authors.forename: Cong-Cong
authors.initials: CC
authors.lastname: Lei
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000453:epidemiology*; D002648:Child; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D003240:Connective Tissue Diseases / Q000453:epidemiology*; D003882:Dermatomyositis / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D017285:Polymyositis / Q000453:epidemiology*; D012189:Retrospective Studies; D012306:Risk; D055815:Young Adult
keywords: Autoimmune diseases; Cancer; Connective tissue diseases; Risk factors; Standardized incidence ratios