Screening for colorectal cancer using the faecal occult blood test, Hemoccult

Background: Colorectal cancer is a leading cause of morbidity and mortality, especially in the Western world. The human and financial costs of this disease have prompted considerable research efforts to evaluate the ability of screening tests to detect the cancer at an early curable stage. Tests tha...

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Main Authors: Hewitson, P, Glasziou, P, Irwig, L, Towler, B, Watson, E
Format: Journal article
Language:English
Published: 2007
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author Hewitson, P
Glasziou, P
Irwig, L
Towler, B
Watson, E
author_facet Hewitson, P
Glasziou, P
Irwig, L
Towler, B
Watson, E
author_sort Hewitson, P
collection OXFORD
description Background: Colorectal cancer is a leading cause of morbidity and mortality, especially in the Western world. The human and financial costs of this disease have prompted considerable research efforts to evaluate the ability of screening tests to detect the cancer at an early curable stage. Tests that have been considered for population screening include variants of the faecal occult blood test, flexible sigmoidoscopy and colonoscopy. Reducing mortality from colorectal cancer (CRC) may be achieved by the introduction of population-based screening programmes. Objectives: To determine whether screening for colorectal cancer using the faecal occult blood test (guaiac or immunochemical) reduces colorectal cancer mortality and to consider the benefits, harms and potential consequences of screening. Search strategy: Published and unpublished data for this review were identified by: • Reviewing studies included in the previous Cochrane review; • Searching several electronic databases (Cochrane Library, Medline, Embase, CINAHL, PsychInfo, Amed, SIGLE, HMIC); and • Writing to the principal investigators of potentially eligible trials. Selection criteria: We included in this review all randomised trials of screening for colorectal cancer that compared faecal occult blood test (guaiac or immunochemical) on more than one occasion with no screening and reported colorectal cancer mortality. Data collection and analysis: Data from the eligible trials were independently extracted by two reviewers. The primary data analysis was performed using the group participants were originally randomised to ('intention to screen'), whether or not they attended screening; a secondary analysis adjusted for non-attendence. We calculated the relative risks and risk differences for each trial, and then overall, using fixed and random effects models (including testing for heterogeneity of effects). We identified nine articles concerning four randomised controlled trials and two controlled trials involving over 320,000 participants with follow-up ranging from 8 to 18 years. Main results: Combined results fromthe 4 eligible randomised controlled trials shows that participants allocated to screening had a 16% reduction in the relative risk of colorectal cancer mortality (RR 0.84, CI: 0.78-0.90). In the 3 studies that used biennial screening (Funen, Minnesota, Nottingham) there was a 15% relative risk reduction (RR 0.85, CI: 0.78-0.92) in colorectal cancer mortality. When adjusted for screening attendance in the individual studies, there was a 25% relative risk reduction (RR 0.75, CI: 0.66 - 0.84) for those attending at least one round of screening using the faecal occult blood test. Authors' conclusions: Benefits of screening include a modest reduction in colorectal cancer mortality, a possible reduction in cancer incidence through the detection and removal of colorectal adenomas, and potentially, the less invasive surgery that earlier treatment of colorectal cancers may involve. Harmful effects of screening include the psycho-social consequences of receiving a false-positive result, the potentially significant complications of colonoscopy or a false-negative result, the possibility of overdiagnosis (leading to unnecessary investigations or treatment) and the complications associated with treatment. Copyright © 2008 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.
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spelling oxford-uuid:ee922d62-5208-487a-92dd-a482366c28b82022-03-27T11:33:51ZScreening for colorectal cancer using the faecal occult blood test, HemoccultJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ee922d62-5208-487a-92dd-a482366c28b8EnglishSymplectic Elements at Oxford2007Hewitson, PGlasziou, PIrwig, LTowler, BWatson, EBackground: Colorectal cancer is a leading cause of morbidity and mortality, especially in the Western world. The human and financial costs of this disease have prompted considerable research efforts to evaluate the ability of screening tests to detect the cancer at an early curable stage. Tests that have been considered for population screening include variants of the faecal occult blood test, flexible sigmoidoscopy and colonoscopy. Reducing mortality from colorectal cancer (CRC) may be achieved by the introduction of population-based screening programmes. Objectives: To determine whether screening for colorectal cancer using the faecal occult blood test (guaiac or immunochemical) reduces colorectal cancer mortality and to consider the benefits, harms and potential consequences of screening. Search strategy: Published and unpublished data for this review were identified by: • Reviewing studies included in the previous Cochrane review; • Searching several electronic databases (Cochrane Library, Medline, Embase, CINAHL, PsychInfo, Amed, SIGLE, HMIC); and • Writing to the principal investigators of potentially eligible trials. Selection criteria: We included in this review all randomised trials of screening for colorectal cancer that compared faecal occult blood test (guaiac or immunochemical) on more than one occasion with no screening and reported colorectal cancer mortality. Data collection and analysis: Data from the eligible trials were independently extracted by two reviewers. The primary data analysis was performed using the group participants were originally randomised to ('intention to screen'), whether or not they attended screening; a secondary analysis adjusted for non-attendence. We calculated the relative risks and risk differences for each trial, and then overall, using fixed and random effects models (including testing for heterogeneity of effects). We identified nine articles concerning four randomised controlled trials and two controlled trials involving over 320,000 participants with follow-up ranging from 8 to 18 years. Main results: Combined results fromthe 4 eligible randomised controlled trials shows that participants allocated to screening had a 16% reduction in the relative risk of colorectal cancer mortality (RR 0.84, CI: 0.78-0.90). In the 3 studies that used biennial screening (Funen, Minnesota, Nottingham) there was a 15% relative risk reduction (RR 0.85, CI: 0.78-0.92) in colorectal cancer mortality. When adjusted for screening attendance in the individual studies, there was a 25% relative risk reduction (RR 0.75, CI: 0.66 - 0.84) for those attending at least one round of screening using the faecal occult blood test. Authors' conclusions: Benefits of screening include a modest reduction in colorectal cancer mortality, a possible reduction in cancer incidence through the detection and removal of colorectal adenomas, and potentially, the less invasive surgery that earlier treatment of colorectal cancers may involve. Harmful effects of screening include the psycho-social consequences of receiving a false-positive result, the potentially significant complications of colonoscopy or a false-negative result, the possibility of overdiagnosis (leading to unnecessary investigations or treatment) and the complications associated with treatment. Copyright © 2008 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.
spellingShingle Hewitson, P
Glasziou, P
Irwig, L
Towler, B
Watson, E
Screening for colorectal cancer using the faecal occult blood test, Hemoccult
title Screening for colorectal cancer using the faecal occult blood test, Hemoccult
title_full Screening for colorectal cancer using the faecal occult blood test, Hemoccult
title_fullStr Screening for colorectal cancer using the faecal occult blood test, Hemoccult
title_full_unstemmed Screening for colorectal cancer using the faecal occult blood test, Hemoccult
title_short Screening for colorectal cancer using the faecal occult blood test, Hemoccult
title_sort screening for colorectal cancer using the faecal occult blood test hemoccult
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