Objective: To review effectiveness of screening for colorectal cancer with faecal occult blood test, Hemoccult, and to consider benefits and harms of screening. Design: Systematic review of trials of Hemoccult screening, with meta-analysis of results from the randomised controlled trials. Subjects: Four randomised controlled trials and two non-randomised trials of about 330 000 and 113 000 people respectively aged >40 years in five countries. Main outcome measures: Meta-analysis of effects of screening on mortality from colorectal cancer. Results: Quality of trial design was generally high, and screening resulted in a favourable shift in the stage distribution of colorectal cancers in the screening groups. Meta-analysis of mortality results from the four randomised controlled trials showed that those allocated to screening had a reduction in mortality from colorectal cancer of 16% (relative risk 0.84 (95% confidence interval 0.77 to 0.93)). When adjusted for attendance for screening, this reduction was 23% (relative risk 0.77 (0.57 to 0.89)) for people actually screened. If a biennial Hemoccult screening programme were offered to 10 000 people and about two thirds attended for at least one Hemoccult test, 8.5 (3.6 to 13.5) deaths from colorectal cancer would be prevented over a period of 10 years. Conclusion: Although benefits of screening are likely to outweigh harms for populations at high risk of colorectal cancer, more information is needed about the harmful effects of screening, the community's responses to screening, and costs of screening for different healthcare systems before widespread screening can be recommended.

All 68,308 inhabitants of Göteborg born between 1918 and 1931 were randomly divided into a test and a control group. The subjects in the test group were invited to perform Hemoccult II fecal occult blood testing on 3 days and to repeat the test after 16 to 24 months. In the prevalence screening 21,347 (63%) performed the test, and in the rescreening 19,991 (60%). Investigation of the 942 (4.4%) with positive tests in the prevalence screening showed 47 cancers and 129 subjects with adenomas > or = 1.0 cm. In the rescreening 5.1% had a positive test, and 34 cancers and 122 subjects with adenomas (> or = 1.0 cm) were found among those. Cancer had also been diagnosed in 19 subjects in the interval between the two screening occasions and in 15 subjects among the non-responders. Forty-four cancers had been diagnosed in the control group during the same period. Cancers detected by screening were at a less advanced stage than in the control group. It is too early to show any effect of screening on mortality from colorectal cancer.

The anorectal function in 3 patients with bilateral and 4 patients with unilateral well-defined loss of sacral nerves after radical tumour excision was studied by clinical examination and by simultaneous registration of the following variables: volume and pressure in the rectum, pressure in the internal anal sphincter area and myoelectrical activity in the external anal sphincter. The patients with bilateral loss of sacral nerves had serious impairment of function. Constipation was their only safeguard against incontinence. The preservation of the first and second sacral nerves bilaterally was not sufficient for discrimination between different qualities of rectal contents passing the anal canal. The sensation of rectal distension was also impaired. The reflex pattern of the internal anal sphincter was, however, intact. The external anal sphincter displayed a weak spontaneous myoelectrical activity in the patients who had at least one second sacral nerve intact, and a weak increase of the activity could be induced voluntarily. The normal transient increase of myoelectrical discharge from the external anal sphincter in response to rectal distension could not, however, be elicited. In patients with total unilateral loss of the sacral nerves no significant impairment of anorectal function was noted. Total one-sided denervation implied deficient sensibility of the anal canal unilaterally, but no disturbance of sphincter function as judged from the reflex response of the internal and external anal sphincters to rectal distension.

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Two hundred thirty-four patients with extensive ulcerative colitis from the city of Göteborg, Sweden have been followed up and the cumulative risk of development of cancer of the large bowel was estimated. These patients constitute all persons in this region who developed an extensive ulcerative colitis between 1951 and 1974. All patients were followed up until December 1975. The mean observation time was 8.5 years, median value six years. Fifteen patients developed carcinoma of the large bowel. Five of the 15 patients were still alive in December 1975. The expected number of colorectal carcinomas in a matched reference group was 0.49. The cumulative incidence of carcinoma 25 years after the onset of colitis for the whole group of patients was 34% and for those who developed the disease before 25 years of age it was 43%.