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Rectal bleeding in general and hospital practice; 'the tip of the iceberg'
Insights
Rectal bleeding is common, but its predictive value for colorectal cancer is low (1:709). Many patients with bleeding do not consult doctors or get referred for investigation, suggesting a need to re-evaluate diagnostic criteria.
Area of Science:
- Gastroenterology
- Oncology
- Epidemiology
Background:
- Rectal bleeding is a common symptom with varying causes.
- Certain characteristics of bleeding, like dark red color and change in bowel habits, have been traditionally associated with a higher risk of colorectal cancer.
- Understanding the incidence and predictive value of rectal bleeding in the general population is crucial for effective screening and diagnosis.
Purpose of the Study:
- To determine the incidence of rectal bleeding in the general population.
- To assess the predictive value of rectal bleeding for colorectal cancer.
- To analyze patient consultation and hospital referral rates for rectal bleeding and characterize benign causes.
Main Methods:
- A postal questionnaire survey was conducted among 6000 randomly selected adults (over 16 years) from three General Practices.
- Data collected included the incidence of rectal bleeding, consultation rates with General Practitioners (GPs), hospital referral rates, and characteristics of bleeding (color, association with bowel habit changes, anal symptoms).
- Colorectal cancer prevalence was determined in subjects reporting rectal bleeding over a 5-year period post-survey.
Main Results:
- 18% of respondents reported rectal bleeding in the previous year.
- Only 28% of those with bleeding consulted their GP, and 7% of those were referred to hospital.
- The predictive value of rectal bleeding for colorectal cancer in the community was low, with only one case diagnosed over 4 years (1:709).
Conclusions:
- Painless rectal bleeding, dark red bleeding, and associated changes in bowel habit are common but have a low predictive value for colorectal cancer.
- A significant proportion of patients with rectal bleeding do not seek medical advice or undergo hospital investigation.
- Current criteria for investigating patients with rectal bleeding may need re-evaluation to ensure appropriate patient selection for diagnostic procedures.
Objective:
To determine the incidence of rectal bleeding and its predictive value for cancer in the general population, patient consultation rates to GPs, referral rates to hospital and the nature of rectal bleeding from benign causes.
Subjects And Methods:
The study was based on a postal questionnaire in the setting of three General Practices in Portsmouth and South-east Hampshire (two in Portsmouth, one in Petersfield). There were 6000 subjects, over the age of 16 years, randomly selected from the three General Practices. The main outcome measures were incidence of rectal bleeding with respect to age and sex, the number who sought medical advice from their GPs and the numbers referred on to hospital. The frequency of dark red bleeding, of an associated change in bowel habit and the presence or absence of anal symptoms were also determined. The prevalence of colorectal cancer was determined in subjects reporting rectal bleeding in the 5-year period after the postal survey.
Results:
Six thousand questionnaires were sent and 4006 (67%) were returned. Of the respondents 18% (709/4006) reported rectal bleeding in the previous year. Four percent (175/4006) had had bleeding for the first time and 38% (1522/4006) had bled at some time in the past. Of the 709 individuals, 512 (72%) had not consulted their GPs. Of the 197 (28%) who did, 50 (1:4, 7%) were referred to hospital. Eighteen percent (125/709) described the blood as dark red, and 88% (621/709) had anal symptoms. In 56% (394/709) the rectal bleeding was associated with a change in bowel habit mostly to hard stools (n=208), fewer to loose stools (n=98). Rectal cancer was diagnosed in only one patient 4 years after the first episode of rectal bleeding, giving a predictive value of rectal bleeding for colorectal cancer in the community of 1:709.
Conclusion:
Many people in the community have painless rectal bleeding, an associated change in bowel habit and dark red bleeding, factors previously thought to indicate a high risk of colorectal cancer. Rectal bleeding has however a low (1:709) predictive value for cancer. As the result of a considerable selection process, only a small number are investigated in hospital. These patients therefore represent a small proportion of all patients with this symptom. The value of the factors used to decide which patients need investigation should be re-assessed.
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