Charles J. Kahi, MD, MSc, FACP, FACG, AGAF; Thomas F. Imperiale, MD, FACP, AGAF
In older adults, does screening with flexible sigmoidoscopy reduce colorectal cancer (CRC) incidence and mortality more than usual care?
Randomized controlled trial (RCT) (Prostate, Lung, Colorectal, and Ovarian [PLCO] Cancer Screening Trial). ClinicalTrials.gov NCT00002540.
Blinded* (cause of death adjudicators).
13 years (mean 11 y).
10 screening centers in the USA.
154 900 participants 55 to 74 years of age (64% < 65 y, 50% women). Exclusion criteria included history of prostate, lung, colorectal, or ovarian cancer; ongoing treatment for cancer other than basal or squamous cell skin cancer; and after 1994, assessment using a lower endoscopic procedure in the past 3 years.
Screening with flexible sigmoidoscopy at baseline and at 3 or 5 years (n = 77 445) or usual care (n = 77 455).
CRC mortality. Other outcomes included CRC incidence, all-cause mortality, and screening-related harms.
99.9% for vital status; compliance with annual study questionnaire was 94% (intention-to-screen analysis).
In the screening group, 83% of participants had flexible sigmoidoscopy at baseline and 54% at 3 or 5 years, 29% had ≥ 1 positive result (mass or polyp detected), and 77% of those with positive results had colonoscopy within 1 year. Flexible sigmoidoscopy screening reduced risk for overall and distal CRC mortality more than usual care; groups did not differ for proximal CRC mortality or mortality from other causes, excluding prostate, lung, colorectal, or ovarian cancer (Table). Screening reduced risk for incident CRC, including distal and proximal cancer (Table). Among participants who had flexible sigmoidoscopy, 20% of men and 13% of women had false-positive results and the rate of perforation among these participants was 107.5 per 100 000 colonoscopies.
In older adults, screening with flexible sigmoidoscopy reduced colorectal cancer incidence and mortality more than usual care.
Colorectal cancer screening with flexible sigmoidoscopy vs usual care in older participants†
†NNS = number needed to invite to screening; other abbreviations defined in Glossary. RRR and CI calculated from risk ratios in article.
‡Distal cancer = cancer in the rectum through the splenic flexure; proximal cancer = cancer in the transverse colon through the cecum.
§Excluding death from prostate, lung, colorectal, and ovarian cancers.
Kahi CJ, Imperiale TF. Flexible sigmoidoscopy screening reduced colorectal cancer incidence and mortality in older adults. Ann Intern Med. 2012;157:JC3–3. doi: 10.7326/0003-4819-157-6-201209180-02003
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Published: Ann Intern Med. 2012;157(6):JC3-3.
Cancer Screening/Prevention, Colonoscopy/Sigmoidoscopy, Colorectal Cancer, Gastroenterology/Hepatology, Gastrointestinal Cancer.
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