Effect of Flexible Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality

Abstract

Importance Colorectal cancer is a major health burden. Screening is recommended in many countries. Objective Estimate the effectiveness of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality in a population-based trial. Design Randomized controlled trial in individuals aged 50–64 years. Screening was performed in 1999–2000 (55–64 year age-group) and 2001 (50–54 year age-group). End of follow-up: Dec 31st 2011. Setting Population of Oslo city and Telemark County, Norway. Participants 100,210 individuals were identified in the screening areas. 1,415 individuals were excluded due to prior colorectal cancer, emigration, or death. Three individuals could not be traced in the population registry. Intervention Individuals randomized to the screening group were invited to screening. Within the screening group, individuals were randomized 1:1 to once-only flexible sigmoidoscopy or combination of once-only flexible sigmoidoscopy and fecal occult blood-testing (FOBT). Individuals with positive screening test (cancer, adenoma, polyp ≥10 mm, or positive FOBT) were offered colonoscopy. The control group received no intervention. Main outcome measures Colorectal cancer incidence and mortality. Results 98,792 individuals were included in the intention to screen analyses; 78,220 in the control group and 20,572 in the screening group (10,283 randomized to flexible sigmoidoscopy and 10,289 to flexible sigmoidoscopy and FOBT). Compliance with screening was 63%. After median 10.9 years, 71 individuals had died from colorectal cancer in the screening group, and 330 in the control group (31.4 vs. 43.1 deaths, absolute rate difference 11.7 (95% CI 3.0–20.4) per 100,000 person-years); hazard ratio [HR] 0.73 (95% confidence interval [CI] 0.56–0.94). Colorectal cancer was diagnosed in 253 individuals in the screening group, and 1,086 in the control group (112.6 vs. 141.0 cases, absolute rate difference: 28.4 (95% CI 12.1–44.7) per 100,000 person-years); HR 0.80 (95% CI 0.70–0.92). Colorectal cancer incidence was reduced in both the 50–54 year age-group (HR 0.68; 95% CI 0.49–0.94) and the 55–64 year age-group (HR 0.83; 95% CI 0.71–0.96). There was no difference between the flexible sigmoidoscopy only and the flexible sigmoidoscopy/FOBT screening groups. Conclusion and relevance In Norway, once-only flexible sigmoidoscopy screening or flexible sigmoidoscopy and FOBT reduced colorectal cancer incidence and mortality on a population level compared with no screening. Screening was effective both in the 50–54 and the 55–64 year age-group. Trial registration ClinicalTrials identifier NTC00119912, http://clinicaltrials.gov

Alternatives to colonoscopy for population-wide colorectal cancer screening

“…Compared with gFOBT, iFOBT undeniably has a higher participation rate, 13,20,33 and even more so compared with FS. 70,71 In a population-wide screening programme with iFOBT, implementation could be achieved in a relatively short period of time as it could be performed by primary care physicians and nurses. Installation of sophisticated hardware is not required.…”

“…70 The positivity rate for adenoma was 17.3%. 71 Most studies were in individuals aged ≥50 [70][71][72] or ≥55 years. 68,69,73 The sensitivity of FS depends on the adequacy of mucosal inspection and is operator-dependent.…”

Optimalisering gjennom randomisering

“…«Klarer vi å ri to hester samtidig, eller blir det dårlig forskning og dårlig folkehelse?» Vi har nå hatt to pilotprosjekter på tarmkreftscreening og begge har vaert randomisering mellom to armer. Deltakelsen har vaert like god eller bedre enn i de landene hvor screeningen har vaert innført uten randomisering (2)(3)(4). Dette har også gitt god forskning.…”

The Effectiveness of a Physician-Only and Physician–Patient Intervention on Colorectal Cancer Screening Discussions Between Providers and African American and Latino Patients

“…1 Effective screening tests include fecal occult blood tests (FOBT), flexible sigmoidoscopy, colonoscopy, or a combination of these tests, [2][3][4][5][6][7] but remain underused, particularly among minorities and those with low income, no insurance, or no usual source of care. 8 The U.S. Preventive Services Task Force currently recommends screening for CRC beginning at age 50 and continuing until age 75, but does not endorse a specific test.…”