title: Screening for Occult Cancer in Unprovoked Venous Thromboembolism.
abstract: BACKGROUND
  Venous thromboembolism may be the earliest sign of cancer. Currently, there is a great diversity in practices regarding screening for occult cancer in a person who has an unprovoked venous thromboembolism. We sought to assess the efficacy of a screening strategy for occult cancer that included comprehensive computed tomography (CT) of the abdomen and pelvis in patients who had a first unprovoked venous thromboembolism.
  
  
  METHODS
  We conducted a multicenter, open-label, randomized, controlled trial in Canada. Patients were randomly assigned to undergo limited occult-cancer screening (basic blood testing, chest radiography, and screening for breast, cervical, and prostate cancer) or limited occult-cancer screening in combination with CT. The primary outcome measure was confirmed cancer that was missed by the screening strategy and detected by the end of the 1-year follow-up period.
  
  
  RESULTS
  Of the 854 patients who underwent randomization, 33 (3.9%) had a new diagnosis of occult cancer between randomization and the 1-year follow-up: 14 of the 431 patients (3.2%) in the limited-screening group and 19 of the 423 patients (4.5%) in the limited-screening-plus-CT group (P=0.28). In the primary outcome analysis, 4 occult cancers (29%) were missed by the limited screening strategy, whereas 5 (26%) were missed by the strategy of limited screening plus CT (P=1.0). There was no significant difference between the two study groups in the mean time to a cancer diagnosis (4.2 months in the limited-screening group and 4.0 months in the limited-screening-plus-CT group, P=0.88) or in cancer-related mortality (1.4% and 0.9%, P=0.75).
  
  
  CONCLUSIONS
  The prevalence of occult cancer was low among patients with a first unprovoked venous thromboembolism. Routine screening with CT of the abdomen and pelvis did not provide a clinically significant benefit. (Funded by the Heart and Stroke Foundation of Canada; SOME ClinicalTrials.gov number, NCT00773448.).
authors.affiliation: From the Department of Medicine (M.C., K.D., G.L.G., P.S.W., M.A.R.) and the Clinical Epidemiology Program (D.J.C., T.R., D.C.), Ottawa Hospital Research Institute, and Department of Diagnostic Imaging (H.T.), University of Ottawa, Ottawa, Departments of Medicine (A.L.-L.), Oncology (A.L.-L.), Epidemiology and Biostatistics (A.L.-L.), and Medical Imaging (Z.K.), University of Western Ontario, London, Department of Medicine, Dalhousie University, Halifax, NS (S. Shivakumar), Department of Medicine, Jewish General Hospital (V.T.), and Department of Medicine, Montreal General Hospital (S. Solymoss), McGill University, and Department of Medicine, Sacre Coeur Hospital, Université de Montréal (N.R., I.C.), Montreal, Department of Medicine, University of Manitoba, Winnipeg (R.Z.), Department of Medicine, McMaster University, Hamilton, ON (J.D.), and the Department of Medicine, University of British Columbia, Vancouver (A.Y.L.) - all in Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Carrier
authors.forename: Alejandro
authors.initials: A
authors.lastname: Lazo-Langner
authors.forename: Sudeep
authors.initials: S
authors.lastname: Shivakumar
authors.forename: Vicky
authors.initials: V
authors.lastname: Tagalakis
authors.forename: Ryan
authors.initials: R
authors.lastname: Zarychanski
authors.forename: Susan
authors.initials: S
authors.lastname: Solymoss
authors.forename: Nathalie
authors.initials: N
authors.lastname: Routhier
authors.forename: James
authors.initials: J
authors.lastname: Douketis
authors.forename: Kim
authors.initials: K
authors.lastname: Danovitch
authors.forename: Agnes Y
authors.initials: AY
authors.lastname: Lee
authors.forename: Gregoire
authors.initials: G
authors.lastname: Le Gal
authors.forename: Philip S
authors.initials: PS
authors.lastname: Wells
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Corsi
authors.forename: Timothy
authors.initials: T
authors.lastname: Ramsay
authors.forename: Doug
authors.initials: D
authors.lastname: Coyle
authors.forename: Isabelle
authors.initials: I
authors.lastname: Chagnon
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kassam
authors.forename: Hardy
authors.initials: H
authors.lastname: Tao
authors.forename: Marc A
authors.initials: MA
authors.lastname: Rodger
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis; D003951:Diagnostic Errors; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging*; D010388:Pelvis / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000175:diagnosis; D011860:Radiography, Abdominal; D014057:Tomography, X-Ray Computed; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis; D054556:Venous Thromboembolism / Q000209:etiology*