title: Colonoscopy first for iron-deficiency anaemia: a Numbers Needed to Investigate approach.
abstract: BACKGROUND
  British Society of Gastroenterology guidelines recommend that gastrointestinal investigations should be considered in males and post-menopausal women presenting with iron-deficiency anaemia (IDA).
  
  
  OBJECTIVE
  To compare the diagnostic yields and clinical effectiveness of upper and lower gastrointestinal (GI) investigation in detecting malignancy among patients presenting with IDA.
  
  
  METHODS
  Retrospective review of case notes, endoscopy records and radiology reports.
  
  
  METHODS
  We reviewed the results of 3798 investigations in 2600 patients presenting to our hospital with IDA from October 1995 to December 2003. The findings of the 2318 gastroscopies were compared with those of the 896 colonoscopies and the 584 barium enemas. Patients diagnosed with GI malignancy were identified and their outcomes determined.
  
  
  RESULTS
  Gastroscopy identified 44 patients with newly-diagnosed upper GI cancer (18 oesophageal, 26 gastric). Thus for patients being gastroscoped for IDA, the Numbers Needed to Investigate (NNI) to detect each cancer was 53. Five-year survival for these 44 patients was 10%, so the NNI to identify each curable upper GI malignancy was 527. Colonoscopy or barium enema identified 111 (7.5%) patients with newly diagnosed colorectal cancer, giving a NNI of 13. Their 5-year survival was 35%, giving a NNI to identify each curable colorectal cancer patient of 38.
  
  
  CONCLUSIONS
  Potentially curable gastrointestinal malignancy was diagnosed over 13 times more commonly using colonoscopy or barium enema vs. gastroscopy. For patients presenting with IDA, our findings favour investigating the lower GI tract first, or performing both gastroscopy and colonoscopy during the same endoscopy list.
authors: Department of Surgery, Royal Gwent Hospital, Cardiff Road, Newport NP20 2UB, UK.
authors: M R
authors: MR
authors: Stephens
authors: A N
authors: AN
authors: Hopper
authors: S R
authors: SR
authors: White
authors: S
authors: S
authors: Jugool
authors: R
authors: R
authors: Stratford
authors: W G
authors: WG
authors: Lewis
authors: M C
authors: MC
authors: Allison