Elsevier

The Lancet

Volume 348, Issue 9040, 30 November 1996, Pages 1467-1471
The Lancet

Articles
Randomised study of screening for colorectal cancer with faecal-occult-blood test

https://doi.org/10.1016/S0140-6736(96)03430-7Get rights and content

Summary

Background

Case-control studies and a voluntary-based follow-up study have suggested that repeated screening with faecal-occult-blood (FOB) tests can lead to a reduction in mortality from colorectal cancer (CRC). The aim of this randomised study was to compare mortality rates after FOB tests every 2 years during a 10-year period with those of unscreened similar controls.

Methods

140 000 people aged 45–75 years lived in Funen, Denmark, in August, 1985, and were considered for inclusion in our study. Before randomisation we excluded individuals who had CRC or precursor adenomas and those who had taken part in a previous pilot study. Randomisation of 137 485 people in blocks of 14 allocated three per 14 to the screening group (30 967), three per 14 to the control group (30 966), and eight not to be enrolled in the study (75 552). Controls were not told about the study and continued to use health-care facilities as normal. Hemoccult-II blood tests (with dietary restrictions but without rehydration) were sent to screening-group participants. Only those participants who completed the first screening round were invited for further screening–five rounds of screening during a 10-year period. Participants with positive tests were asked to attend a full examination and were offered colonoscopy whenever possible. The primary endpoint was death from CRC.

Findings

Of the 30 967 screening-group participants, 20 672 (67%) completed the first screening round and were invited for further screening; more than 90% accepted repeated screenings. During the 10-year study, 481 people in the screening group had a diagnosis of CRC, compared with 483 unscreened controls. There were 205 deaths attributable to CRC in the screening group, compared with 249 deaths in controls. CRC mortality, including deaths attributable to complications from CRC treatment, was significantly lower in the screening group than in controls (mortality ratio 0·82 [95% CI 0·68–0·99]) p=0·03).

Interpretation

Our findings indicate that biennial screening by FOB tests can reduce CRC mortality. This study is being continued to improve its statistical power and to assess the effect of the removal of more precursor adenomas in the screening-group participants than in controls on CRC incidence.

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)

  • JD Hardcastle et al.

    Randomised controlled trial of faecal occult blood screening for colorectal cancer: results for first 107 349 subjects

    Lancet

    (1989)
  • JV Selby et al.

    Effect of fecal occult blood testing on mortality from colorectal cancer: a case-control study

    Ann Int Med

    (1993)
  • J Wahrendorf et al.

    Effectiveness of colorectal cancer screening: results from a population-based case-control evaluation in Saarland, Germany

    Eur J Cancer Prev

    (1993)
  • SJ Winawer et al.

    Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy

    J Natl Cancer Inst

    (1993)
  • JS Mandel et al.

    Reducing mortality from colorectal cancer by screening for fecal occult blood

    N Engl J Med

    (1993)
  • J Kewenter et al.

    Screening and re-screening for colorectal cancer: a controlled trial of fecal occult blood testing in 27 700 subjects

    Cancer

    (1988)
There are more references available in the full text version of this article.

Cited by (2228)

  • Principles of cancer screening

    2024, Surgery (United Kingdom)
View all citing articles on Scopus
View full text