title: The risk of a diagnosis of cancer after primary deep venous thrombosis or pulmonary embolism.
abstract: BACKGROUND
  Several small studies have indicated an association between deep venous thrombosis or pulmonary embolism and a subsequent diagnosis of cancer, but the subject is controversial.
  
  
  METHODS
  We conducted a nationwide study of a cohort of patients with deep venous thrombosis or pulmonary embolism that was drawn from the Danish National Registry of Patients for the years 1977 through 1992. The occurrence of cancer in the cohort was determined by linkage to the Danish Cancer Registry. The expected number of cancer cases was estimated on the basis of national age-, sex-, and site-specific incidence rates.
  
  
  RESULTS
  A total of 15,348 patients with deep venous thrombosis and 11,305 patients with pulmonary embolism were identified. We observed 1737 cases of cancer in the cohort with deep venous thrombosis, as compared with 1372 expected cases (standardized incidence ratio, 1.3; 95 percent confidence interval, 1.21 to 1.33). Among the patients with pulmonary embolism, the standardized incidence ratio was 1.3, with a 95 percent confidence interval of 1.22 to 1.41. The risk was substantially elevated only during the first six months of follow-up and declined rapidly thereafter to a constant level slightly above 1.0 one year after the thrombotic event. Forty percent of the patients given a diagnosis of cancer within one year after hospitalization for thromboembolism had distant metastases at the time of the diagnosis of cancer. There were strong associations with several cancers, most pronounced for those of the pancreas, ovary, liver (primary hepatic cancer), and brain.
  
  
  CONCLUSIONS
  An aggressive search for a hidden cancer in a patient with a primary deep venous thrombosis or pulmonary embolism is not warranted.
authors.affiliation: Danish Epidemiology Science Center at the Department of Epidemiology and Social Medicine, University of Aarhus.
authors.forename: H T
authors.initials: HT
authors.lastname: Sørensen
authors.forename: L
authors.initials: L
authors.lastname: Mellemkjaer
authors.forename: F H
authors.initials: FH
authors.lastname: Steffensen
authors.forename: J H
authors.initials: JH
authors.lastname: Olsen
authors.forename: G L
authors.initials: GL
authors.lastname: Nielsen
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology*; D016017:Odds Ratio; D011655:Pulmonary Embolism / Q000150:complications*; D012307:Risk Factors; D013924:Thrombophlebitis / Q000150:complications*