ArticlesRandomised study of screening for colorectal cancer with faecal-occult-blood test
Introduction
Denmark has high incidence and mortality rates for colorectal cancer (CRC)—the incidence of colonic cancer is currently increasing and mortality remains constant, whereas incidence and mortality of rectal cancer are declining. Early stages of CRC are commonly found in only 10–15% of patients with symptoms. However, there is evidence that earlier diagnosis and treatment of CRC in symptom-free patients may reduce mortality. Two case-control studies of screening with faecal-occult-blood (FOB) tests reported reductions in CRC mortality rates of 31%1 and 57%2 (the latter reduction was found only in women). Similarly, Winawer and colleagues' non-randomised study3 showed that annual rigid sigmoidoscopy and FOB tests, rather than sigmoidoscopy alone, led to a reduction in mortality. Mandel and colleagues' voluntary-based randomised study in Minnesota4 (ie, all participants were informed about randomisation), reported a 33% reduction in CRC mortality rates after 13 years in patients who were offered annual screening for FOB, but a non-significant reduction of 6% in those who were offered biennial screening. Four randomised population trials of screening with FOB tests are under way in Europe,5, 6, 7, 8 but no mortality figures have until now been reported. The main aim of this study was to compare deaths from CRC after biennial screening by FOB tests with deaths from CRC in a similar unscreened population (controls) during a 10-year period.
Section snippets
Methods
This study followed a pilot study of compliance in screening for CRC in which of 685 people, 460 (67%) accepted the Hemoccult-II test.9 We intended to use three screening rounds with FOB tests during a 5-year period, followed by 5 years of follow-up based on passive case detection. However, after 5 years, the compliance was good and we decided to continue biennial screening for a further 5 years; thus, the study period was from August, 1985, to August, 1995.
Based on the assumption of a CRC
Results
The groups were well matched in terms of age and sex at the initial screening (table 1). The age and sex distributions of the groups did not change substantially during the study. The study profile shows overall patient numbers during the 10-year study (figure 1). 205 people died between randomisation and planned invitation for screening. Of the 49 402 people who were alive at the end of the follow-up, 1145 had moved away from Funen and six had emigrated from Denmark. The number of individuals
Discussion
We found that after 10 years of follow-up, screening by FOB every 2 years (Hemoccult-II without rehydration) led to a reduction of 18% in CRC mortality, which was independent of sex and age, in individuals aged 45–75 years. Of the 20 672 participants who were screened at least once only 892 (4·3%) underwent colonoscopy. Our findings contrast with those of the Minnesota study,4 in which 38% of people who were screened annually during a period of 13 years had colonoscopy (with an intermission of
References (13)
- et al.
Randomised controlled trial of faecal occult blood screening for colorectal cancer: results for first 107 349 subjects
Lancet
(1989) - et al.
Effect of fecal occult blood testing on mortality from colorectal cancer: a case-control study
Ann Int Med
(1993) - et al.
Effectiveness of colorectal cancer screening: results from a population-based case-control evaluation in Saarland, Germany
Eur J Cancer Prev
(1993) - et al.
Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy
J Natl Cancer Inst
(1993) - et al.
Reducing mortality from colorectal cancer by screening for fecal occult blood
N Engl J Med
(1993) - et al.
Screening and re-screening for colorectal cancer: a controlled trial of fecal occult blood testing in 27 700 subjects
Cancer
(1988)