Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force.
OBJECTIVE
Colorectal cancer (CRC) remains a significant cause of morbidity and mortality in the United States.


OBJECTIVE
To systematically review the effectiveness, diagnostic accuracy, and harms of screening for CRC.


METHODS
Searches of MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant studies published from January 1, 2008, through December 31, 2014, with surveillance through February 23, 2016.


METHODS
English-language studies conducted in asymptomatic populations at general risk of CRC.


METHODS
Two reviewers independently appraised the articles and extracted relevant study data from fair- or good-quality studies. Random-effects meta-analyses were conducted.


METHODS
Colorectal cancer incidence and mortality, test accuracy in detecting CRC or adenomas, and serious adverse events.


RESULTS
Four pragmatic randomized clinical trials (RCTs) evaluating 1-time or 2-time flexible sigmoidoscopy (n = 458,002) were associated with decreased CRC-specific mortality compared with no screening (incidence rate ratio, 0.73; 95% CI, 0.66-0.82). Five RCTs with multiple rounds of biennial screening with guaiac-based fecal occult blood testing (n = 419,966) showed reduced CRC-specific mortality (relative risk [RR], 0.91; 95% CI, 0.84-0.98, at 19.5 years to RR, 0.78; 95% CI, 0.65-0.93, at 30 years). Seven studies of computed tomographic colonography (CTC) with bowel preparation demonstrated per-person sensitivity and specificity to detect adenomas 6 mm and larger comparable with colonoscopy (sensitivity from 73% [95% CI, 58%-84%] to 98% [95% CI, 91%-100%]; specificity from 89% [95% CI, 84%-93%] to 91% [95% CI, 88%-93%]); variability and imprecision may be due to differences in study designs or CTC protocols. Sensitivity of colonoscopy to detect adenomas 6 mm or larger ranged from 75% (95% CI, 63%-84%) to 93% (95% CI, 88%-96%). On the basis of a single stool specimen, the most commonly evaluated families of fecal immunochemical tests (FITs) demonstrated good sensitivity (range, 73%-88%) and specificity (range, 90%-96%). One study (n = 9989) found that FIT plus stool DNA test had better sensitivity in detecting CRC than FIT alone (92%) but lower specificity (84%). Serious adverse events from colonoscopy in asymptomatic persons included perforations (4/10,000 procedures, 95% CI, 2-5 in 10,000) and major bleeds (8/10,000 procedures, 95% CI, 5-14 in 10,000). Computed tomographic colonography may have harms resulting from low-dose ionizing radiation exposure or identification of extracolonic findings.


CONCLUSIONS
Colonoscopy, flexible sigmoidoscopy, CTC, and stool tests have differing levels of evidence to support their use, ability to detect cancer and precursor lesions, and risk of serious adverse events in average-risk adults. Although CRC screening has a large body of supporting evidence, additional research is still needed.
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Jennifer S
JS
Lin
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Margaret A
MA
Piper
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Leslie A
LA
Perdue
Group Health Research Institute, Seattle, Washington3Currently with RAND Corporation, Santa Monica, California.
Carolyn M
CM
Rutter
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Elizabeth M
EM
Webber
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Elizabeth
E
O'Connor
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Ning
N
Smith
Kaiser Permanente Research Affiliates Evidence-based Practice Center, Center for Health Research, Kaiser Permanente, Portland, Oregon.
Evelyn P
EP
Whitlock
D000236:Adenoma / Q000175:diagnosis*; D026683:Advisory Committees; D058070:Asymptomatic Diseases; D023881:Colonography, Computed Tomographic / Q000706:statistics & numerical data; D003113:Colonoscopy / Q000009:adverse effects / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000401:mortality; D004247:DNA / Q000032:analysis; D000068598:Data Accuracy; D005243:Feces / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry / Q000706:statistics & numerical data; D033162:Incidental Findings; D009780:Occult Blood; D011314:Preventive Health Services; D016032:Randomized Controlled Trials as Topic; D012680:Sensitivity and Specificity; D012812:Sigmoidoscopy / Q000706:statistics & numerical data; D014481:United States
D004247:DNA