title: Unprovoked venous thromboembolism and subsequent cancer risk: a population-based cohort study.
abstract: ESSENTIALS: A relationship between unprovoked venous thromboembolism (VTE) and cancer risk was investigated. We collected 27,751 VTE patients and compared them with 110,409 frequency-matched people without VTE. This cohort study showed significantly higher risks of overall and site-specific cancers in the VTE group. There is an increased risk in the first 6 months after VTE, and VTE can be an indicator of occult cancer.
  
  
  CONCLUSIONS
  
  
  
  BACKGROUND
  We investigated the relationship between unprovoked venous thromboembolism (VTE) and subsequent cancer risk in Taiwan, focusing on both short-term and long-term cancer development.
  
  
  METHODS
  For the case group, we obtained data on 27,751 patients diagnosed with unprovoked VTE between 1 January 1998, and 31 December 2008. For the comparison group, four people without unprovoked VTE were frequency-matched with each unprovoked VTE patient according to age, sex, and index year. Cox proportional hazards regression models were employed to determine the effects of unprovoked VTE on cancer risk.
  
  
  RESULTS
  Overall cancer risk was significantly higher in the unprovoked VTE group than in the comparison group (adjusted hazard ratio = 2.26, 95% confidence interval = 2.16-2.37). The increased risk was observed in both men and women in various age groups. The patients in the unprovoked VTE group showed a significantly increased risk of cancer at all site-specific cancer sites. Analyses stratified according to follow-up duration revealed that significant differences were more evident between the two groups over a follow-up duration of < 0.5 years than over a follow-up duration of ≥ 3 years. Furthermore, the 1-year mortality risk of cancer patients with unprovoked VTE was significantly higher than that for cancer patients in the non-VTE group.
  
  
  CONCLUSIONS
  The results of this study show that unprovoked VTE is associated with a consistently high risk of subsequent cancer diagnosis. This is particularly true in the first 6 months after VTE. It suggests that unprovoked VTE can be an indicator of occult malignancy.
authors.affiliation: Department of Radiation Oncology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan.
authors.forename: L-M
authors.initials: LM
authors.lastname: Sun
authors.affiliation: Department of Internal Medicine, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan.|Department of Health Services Administration, China Medical University, Taichung, Taiwan.|Department of Healthcare Administration, Central Taiwan University of Science and Technology, Taichung, Taiwan.
authors.forename: W-S
authors.initials: WS
authors.lastname: Chung
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan.|College of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: C-L
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Graduate Institute of Clinical Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.|Department of Radiation Oncology, China Medical University Hospital, Taichung, Taiwan.
authors.forename: J-A
authors.initials: JA
authors.lastname: Liang
authors.affiliation: Graduate Institute of Clinical Medical Science, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.|Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.
authors.forename: C-H
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D016009:Chi-Square Distribution; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009369:Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D016017:Odds Ratio; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors; D054556:Venous Thromboembolism / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult
keywords: ICD-9; cohort study; neoplasms; risk; venous thromboembolism