Ronald L. Koretz, MD
What are the relative participation rates and diagnostic yields of an invitation for colorectal cancer screening by colonoscopy or noncathartic computed tomography (CT) colonography?
Population-based, cluster (household), randomized, controlled trial (COlonoscopy or COlonography for Screening [COCOS] trial). Dutch trial register NTR1829.
1 month after screening.
Amsterdam and Rotterdam, The Netherlands.
8844 randomly selected residents 50 to 75 years of age (mean age 61 y, 50% men) who had not previously been invited for colorectal cancer screening. Exclusion criteria were colonoscopy, CT colonography, or double-contrast barium enema in the past 5 years; and life expectancy < 5 years. Further exclusion criteria from CT colonography were pregnancy, hyperthyroidism, iodine contrast medium allergy, and exposure to ionizing radiation in the past 12 months for research purposes.
Invitation by mail for colorectal cancer screening by colonoscopy (n = 5924) or noncathartic CT colonography (n = 2920). Invitations included a brochure about colorectal cancer and advantages and risks associated with the specified test. Participants consulted with a nurse or physician before the test.
Primary outcome was participation rate (screening examinations done) per total number of invitees. Secondary outcome was diagnostic yield (number of participants with advanced neoplasia [adenoma ≥ 10 mm, any adenoma with ≥ 25% villous histology or high-grade dysplasia, or colorectal cancer] relative to the number of participants who completed screening and to the number of invitees).
100% of invitees (intention-to-treat). 98% of patients who participated in screening had completed procedures.
2258 patients (26%) participated in screening. Participation rates were lower for colonoscopy than for CT colonography (Table). Diagnostic yield for advanced neoplasia did not differ between groups per 100 invitees but was higher with colonoscopy than with CT colonography per 100 participants (Table).
Patients invited for colorectal cancer screening with colonoscopy had a lower participation rate than those invited for screening with noncathartic CT colonography. Colonoscopy had a higher diagnostic yield for advanced neoplasia per participant but a similar yield per invitee compared with CT colonography.
Invitation for colorectal cancer screening by colonoscopy vs noncathartic CT colonography†
†CT = computed tomography; other abbreviations defined in Glossary.
‡Diagnostic yield of ≥ 1 advanced neoplasm.
Koretz RL. Invitation to screening with colonoscopy had lower participation but similar yield as CT colonography. Ann Intern Med. ;157:JC1–5. doi: 10.7326/0003-4819-157-2-201207170-02005
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Published: Ann Intern Med. 2012;157(2):JC1-5.
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