Colonoscopy first for iron-deficiency anaemia: a Numbers Needed to Investigate approach

Area of Science:

• Gastroenterology
• Oncology
• Diagnostic Medicine

Background:

• British Society of Gastroenterology guidelines recommend gastrointestinal investigations for males and post-menopausal women with iron-deficiency anaemia (IDA).
• The diagnostic yield and clinical effectiveness of upper vs. lower GI investigations in detecting malignancy in IDA patients require comparison.

Purpose of the Study:

• To compare the diagnostic yields and clinical effectiveness of upper and lower gastrointestinal (GI) investigations in detecting malignancy among patients presenting with IDA.

Main Methods:

• Retrospective review of case notes, endoscopy records, and radiology reports.
• Analysis of 3798 investigations (2318 gastroscopies, 896 colonoscopies, 584 barium enemas) in 2600 patients with IDA (Oct 1995-Dec 2003).
• Identification of GI malignancy diagnoses and patient outcomes.

Main Results:

• Gastroscopy detected 44 upper GI cancers (NNI=53), with a 5-year survival of 10% (NNI for curable cancer=527).
• Colonoscopy/barium enema detected 111 colorectal cancers (NNI=13), with a 5-year survival of 35% (NNI for curable cancer=38).
• Potentially curable GI malignancy was diagnosed over 13 times more frequently with lower GI investigations.

Conclusions:

• For patients with IDA, lower GI tract investigation (colonoscopy or barium enema) is more effective for diagnosing potentially curable cancers compared to upper GI investigation (gastroscopy).
• Findings support prioritizing lower GI investigation or performing both upper and lower GI investigations during the same endoscopy session for IDA patients.