title: Incidence of pulmonary embolism in patients with newly diagnosed colorectal cancer.
abstract: BACKGROUND
  Studies have suggested a benefit from extended venous thromboprophylaxis post-operatively in colorectal cancer with an assumed base rate of zero venous thromboembolic events prior to treatment. We aim to establish the incidence of pulmonary embolism in patients with newly diagnosed stage III or IV colorectal cancer prior to any treatment.
  
  
  METHODS
  Consecutive patients presenting to a single health service with a new diagnosis of stage III or IV colorectal cancer were identified from a prospective database, for the period between January 2011 and September 2014. Contemporaneous clinical data was reviewed. Included patients had a computerized tomography (CT) chest scan for pre-operative staging for cancer. The diagnosis of pulmonary emboli was made on chest CT.
  
  
  RESULTS
  Of 330 patients identified, 224 had baseline CT chest imaging available for review, of which 107 (47.8%) were technically adequate scans. Pulmonary emboli were identified on five (4.7%) of these 107, including one of five patients (1.7%) with stage III and four of five patients (8.3%) with stage IV disease. None of the 107 patients with adequate scans had post-operative pulmonary emboli or deep vein thrombosis.
  
  
  CONCLUSIONS
  There is a clinically significant baseline rate of asymptomatic pulmonary emboli in patients with stage III and IV colorectal cancer that can be demonstrated on the staging chest CT scan. Pulmonary emboli described as a post-operative event in previous series may have been present prior to surgery.
authors.affiliation: Colorectal Unit, Western Hospital, Melbourne, Victoria, Australia.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Daniel
authors.affiliation: Colorectal Unit, Western Hospital, Melbourne, Victoria, Australia.
authors.forename: Anastasia E
authors.initials: AE
authors.lastname: Dean
authors.affiliation: Radiology Department, Western Hospital, Melbourne, Victoria, Australia.
authors.forename: Mingjoe
authors.initials: M
authors.lastname: Lim
authors.affiliation: Radiology Department, Western Hospital, Melbourne, Victoria, Australia.
authors.forename: Mobin
authors.initials: M
authors.lastname: Master
authors.affiliation: Oncology Unit, Royal Melbourne Hospital, Melbourne, Victoria, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Gibbs
authors.affiliation: Colorectal Unit, Western Hospital, Melbourne, Victoria, Australia.
authors.forename: Ian
authors.initials: I
authors.lastname: Faragher
mesh_terms: D000230:Adenocarcinoma / Q000150:complications / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000150:complications / Q000175:diagnosis*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000453:epidemiology*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
keywords: colorectal cancer; pulmonary embolism