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The aim of the study is to determine the diagnostic value of (combinations of) signs, symptoms and simple laboratory test results for colorectal cancer in patients with rectal bleeding presenting in general practice. Initial complaints and findings were compared with the final diagnoses based on clinical follow-up after at least 1 year. Patients studied were those presenting overt rectal bleeding to the general practitioner (83 GPs in the South of the Netherlands). Outcome measures are sensitivity, specificity, predictive values, odds ratios and a prediction model derived from multiple logistic regression analysis. Age, change in bowel habit and blood mixed with or on stool show a statistically significant independent value in the discrimination between patients with a low and those with a high probability of colorectal cancer. Many other variables did not show predictive value. The prediction model has a sensitivitiy of 100% and a specificity of 90%. Although the number of patients with colorectal cancer is small (n = 9) it was possible to identify three characteristics which can be helpful in the prediction of presence or absence of colorectal cancer in general practice. Application of the model presented might prevent 90% of 'unnecessary' invasive diagnostic procedures for patients with rectal bleeding who do not have colorectal cancer (true negative). Testing the performance of the model in other general practice populations is recommended.

Five hundred and seventy-eight consecutive cases of non-acute abdominal pain presenting to 11 general practices were included in a descriptive study and were followed during 15 months. Females predominated in the younger age groups. Eighty per cent of these patients visited their GP not more than three times for abdominal complaints during the follow-up period. Eighty-three per cent were managed entirely in the practice and 64% received a prescription. Only 20% of patients were additionally investigated in any way by the GP. There were hardly any differences in final diagnoses between patients who had complaints less than 1 week or more than 1 week before presenting to the GP. Non-acute abdominal pain is a condition that is seen and managed mainly in general practice.

The objective of the studies reported in this paper was to determine the incidence as well as the final diagnostic outcome of rectal bleeding presenting in general practice. Because of the wide variety observed in incidence rates among 83 general practitioners (GPs) in the first study (A) an additional study (B) was undertaken. In study B with 10 GPs special efforts were made to maximize the catchment rate. The mean 'consultation incidence rate' was 7 per 1000 people per year. A follow-up period of at least 1 year was applied to establish the final diagnostic conclusion. Occurrence of colorectal cancer was found in 3% of patients with rectal bleeding. This may represent an overestimation of the prior probability since there was a selection in favour of patients with clinically relevant rectal bleeding. In about 90% of patients rectal bleeding was related to minor ailments or self-limiting disorders. Further study on predictive values of (combinations of) other signs and symptoms is necessary to develop clinical recommendations.

The rectal examination is a much advocated procedure for assessing abdominal and urinary symptoms. A Medline literature search yielded only a few studies, not one of them in a general practice setting. The sensitivity of the rectal examination to rectal carcinoma and appendicitis is low, while it is high for prostate carcinoma. When reviewing the likelihood ratios of normal and abnormal findings of rectal examinations it was concluded that it may be a useful procedure in the case of abnormal findings in patients presenting rectal problems and in assessing men with prostate problems, although it does not seem useful in diagnosing appendicitis. However, since the diagnostic values in general practice and in referred populations may be different, there is a need for further prospective studies in settings of general medical practice.

In most textbooks of gastroenterology, diseases with their symptoms are discussed. The exact diagnostic value of these symptoms, however, regarding the differentiation between organic and functional disease, is not mentioned. A criteria-based meta-analysis of the few existing studies in this field was done. From the 14 identified studies, there were two that did not find any significant symptoms. In the other studies the diagnostic value of colonic symptoms showed great variability. Methodological deficiencies in these studies are probably responsible for the latter. The generalization of these results into general practice is not straightforward and needs research in general practice patients.