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Rectal bleeding is a recognized early symptom of colorectal cancer.
Dr Olde Bekkink and colleagues from Ireland assessed the diagnostic accuracy of symptoms, signs and diagnostic tests in patients with rectal bleeding in relation to risk of colorectal cancer in primary care.
The team reviewed diagnostic accuracy systematic.
The research team searched Medline, Embase, British Nursing Index and PsychINFO were searched.
 | | The average weighted prior probability of colorectal cancer was 7% | | British Journal of Cancer |
The team included cohort studies that assessed the diagnostic utility of rectal bleeding in combination with other symptoms, signs and diagnostic tests in primary care.
An eight-point quality assessment tool was produced to assess the quality of included studies.
The researchers evaluated 8 studies incorporating 2,323 patients.
The research team found that the average weighted prior probability of colorectal cancer was 7%.
Age 60 years, weight loss, and change in bowel habit raise the probability of colorectal cancer into the range of referral to secondary care but do not conclusively ‘rule in’ the diagnosis.
Presence of severe anaemia has the highest diagnostic value, specificity 0.95, but still only generates a post-test probability of 22%.
Dr Bekkink's team concluded, “In patients with rectal bleeding who present to their general practitioner, additional ‘red flag’ symptoms have modest diagnostic value.”
“These findings have implications in relation to recommendations contained in clinical practice guidelines.”
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