An analysis of site-specific attributable pathologies for colorectal symptoms: Diagnostic yield of colonoscopy

The aim of this prospective study was to audit the diagnostic yield of colonoscopy for an unselected cohort of patients referred with lower intestinal symptoms. Seven hundred and forty-four consecutive patients over a 12-month period were analysed. The main reasons for referral included rectal bleeding, iron deficiency anaemia, altered bowel habit, abdominal pain, colonoscopic follow up (for colitis, prior endoscopic polypectomy and after colorectal cancer resection) and screening (positive family history of colorectal cancer). Rectal bleeding had a diagnostic yield of 69.4% (neoplastic yield of 23.8%). Over 50% of patients with anaemia had normal colonoscopies (23.7% yield for colorectal neoplasia). Only one carcinoma was found in 133 patients colonoscoped for abdominal pain or altered bowel habit (0.75%). New carcinoma diagnoses were made in 1.6% (1/59) of patients followed up after cancer resection and in 1.5% of those patients with prior endoscopic polypectomy (1/65). Colonoscopy is valuable as a routine investigation in patients presenting with rectal bleeding or iron deficiency anaemia.