Colorectal cancer screening with the addition of flexible sigmoidoscopy to guaiac-based fecal occult blood testing: a population-based controlled trial

B Denis, I Gendre, Pfeiffer JC, Weiss AM, Vagne F, Peter A, Perrin P


to assess feasibility, compliance and yield of the addition of flexible sigmoidoscopy (FS) to an organized colorectal cancer (CRC) screening program with guaiac-based fecal occult blood test (gFOBT).


All 185,000 residents of the district of the Haut-Rhin aged 50-74 have been invited since 2003 to participate in an organized CRC screening program with biennial gFOBT. In addition, all residents of a canton aged 55-64 were invited by mail from July 2006 to July 2007 to visit their general practitioner (GP) for a screening with FS. FS was performed by gastroenterologists using an upper video-endoscope. People with positive gFOBT or any neoplasia at FS were referred for colonoscopy. Results: Main results are presented in the table below. Of 2322 residents aged 55-64, 421 were excluded from the screening program with gFOBT and 77 from the FS trial. 370 (20.3%) of 1824 eligible average risk people performed both tests. Compliance with FS was 1.8% in people who did not comply with gFOBT and 32.0% in people having performed a gFOBT. The latter was ≥ 50% in patients of 26 motivated GPs. Compliance with FS was higher in men than in women (23.8% vs. 18.2%) and in people aged 60-64 than in 55-59 (26.2% vs. 17.6%)(p<0.01). 341 (89.3%) FS examinations were adequate. 87.3% of participants experienced no pain or only mild pain and 97.7% were satisfied and ready to do it again. There was no serious complication (3 vasovagal reactions). FS screening yield was not different between 179 people with 1 previous negative gFOBT (1 (0.6%) subject with a distal cancer and 17 (9.5%) with an advanced adenoma) and 190 people with 2 previous negative gFOBT (respectively 1 (0.5%) and 13 (6.8%)). The advanced neoplasia yield was significantly higher in men (12.7% vs. 4.1%)(p<0.01). Adopting any ≥ 5 mm polyp (any advanced neoplasia) as a threshold would reduce the rate of referral for colonoscopy by 35% (50%) and the advanced neoplasia yield by 23.5% (26.5%).


A population-based screening program with the addition of FS to gFOBT was feasible and safe through an organisation involving GPs. Despite a 3 times lower compliance, the advanced neoplasia yield was 3 times higher with the combined procedure than with gFOBT alone. Compliance with FS can be significantly enhanced by motivated GPs. A single FS screening in people aged 55-64 is worth adding to an organized program with biennial gFOBT in people aged 50-74 as their performances are complementary: high compliance – low yield for gFOBT and vice versa for FS.


eligible people

participants n (%)

positive tests n (%)

colonoscopic procedures

advanced neoplasia n (per 1000 eligible)

proximal advanced neoplasia n (per 1000 eligible)



37642 (60,9%)

1257 (3,3%)


324 (5,2)

53 (0,9)



382 (20,9%)

64 (16,8%)


34 (18,6)

4 (2,2)

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