Introduction NICE guidelines recommend that patients with rectal bleeding at risk of cancer should be referred for further investigation.¹The choice of investigation is at the discretion of the clinician. A retrospective study of patients who underwent curative resection of proximal colorectal malignancy reported a 3% chance of missing right-sided cancers if flexible sigmoidoscopy alone is performed.²The aim of our study was to evaluate the incidence of right-sided malignancy in patients undergoing colonoscopy for rectal bleeding, to stratify this risk by age, and to compare these rates in 2 different patient populations.

Method The endoscopy databases at St George’s Hospital, London (SGH) and Royal Surrey County Hospital (RSCH) were interrogated to identify all colonoscopies performed for rectal bleeding. Data were available over 32 (SGH) and 26 (RSCH) years. Results were stratified according to age and location of pathology, and differences between the 2 populations were analysed using Z-test.

Results A total of 10482 colonoscopies were performed for rectal bleeding. 849 (8.1%) identified lesions suspicious for cancer. Of all suspected cancers, 94 (11.2%) were right-sided. The overall incidence of right-sided cancer was 0.9%.

Overall incidence of right-sided cancer found at endoscopy in patients investigated for rectal bleeding in both units and stratified by age:

Sub-analysis of the SGH data revealed that 54.1% of patients with right-sided lesions would have been found to have an indication to undertake completion colonoscopy had a flexible sigmoidoscopy been undertaken in the first instance.

Conclusion These data provide an estimate of the age-specific risk of right-sided CRC in patients presenting with rectal bleeding. No significant difference regarding cancer incidence between our 2 diverse patient populations could be demonstrated, suggesting that these results might be generalisable to a wider population. The overall yield of right-sided cancer across age ranges remains low. We propose that flexible sigmoidoscopy might reasonably be offered to all patients presenting with rectal bleeding, regardless of age, as a first line investigation. Adopting such a strategy will likely result in cost-savings and have beneficial waiting list implications, without engendering risk of missing significant pathology.

Disclosure of interest None Declared.

References

1. BSG Clinical Commisioning Report for Rectal Bleeding [last accessed 11/2/15]

2. Badiani S, Desai A and Chapman MAS. Is whole colonic imaging necessary for symptoms of change in bowel habit and/or rectal bleeding? Colorectal disease. 2012;14:1197–1200