Risk of Incident Colorectal Cancer and Death After Colonoscopy: A Population-based Study in Utah.
OBJECTIVE
Colonoscopy is widely recommended for colorectal (CRC) screening in the United States, but evidence of effectiveness is limited. We examined whether exposure to colonoscopy decreases the odds of incident CRC and death from CRC in Utah.


METHODS
We performed a case-control study of Utah residents, 54 to 90 years old, who received a CRC diagnosis from 2000 through 2010 (cases). Age- and sex-matched controls with no history of CRC (controls) were selected for each case. We determined receipt of colonoscopy 6 months to 10 years before the reference date for each case and control through administrative claims data. Colonoscopy exposure was compared by using conditional logistic regression.


RESULTS
We identified 5128 cases and 20,512 controls; 741 cases (14%) and 5715 controls (28%) received a colonoscopy. Exposure to colonoscopy reduced the odds for a diagnosis of CRC; the odds ratios (ORs) were 0.41 for any CRC (95% confidence interval [CI], 0.38-0.44), 0.58 for proximal colon cancer (95% CI, 0.51-0.65), and 0.29 for distal colon or rectal cancer (95% CI, 0.25-0.33). This finding was consistent among sexes, age groups, and cancer stages. Similarly, in a subgroup analysis, colonoscopy was associated with decreased odds of death from CRC (OR, 0.33; 95% CI, 0.28-0.39) in both the proximal colon (OR, 0.43; 95% CI, 0.34-0.55) and distal colon or rectum (OR, 0.23; 95% CI, 0.18-0.30).


CONCLUSIONS
In the population of Utah, colonoscopy is associated with a large reduction in risk of new-onset CRC and death from CRC. This reduction in risk for CRC was greatest for the distal colon and rectum, with a more modest reduction for proximal colon cancer.
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, Utah. Electronic address: Jewel.samadder@hsc.utah.edu.
N Jewel
NJ
Samadder
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Medicine (Genetic Epidemiology), University of Utah, Salt Lake City, Utah; Utah Population Database, University of Utah, Salt Lake City, Utah.
Karen
K
Curtin
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
Lisa
L
Pappas
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Population Sciences, University of Utah, Salt Lake City, Utah.
Ken
K
Boucher
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Utah Population Database, University of Utah, Salt Lake City, Utah; Department of Oncological Sciences, University of Utah, Salt Lake City, Utah.
Geraldine P
GP
Mineau
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Utah Population Database, University of Utah, Salt Lake City, Utah; Department of Oncological Sciences, University of Utah, Salt Lake City, Utah; Department of Family and Consumer Studies, University of Utah, Salt Lake City, Utah.
Ken
K
Smith
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Utah Population Database, University of Utah, Salt Lake City, Utah.
Alison
A
Fraser
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Utah Population Database, University of Utah, Salt Lake City, Utah.
Yuan
Y
Wan
Durham Epidemiologic Research and Information Center (ERIC), Durham VAMC, Durham, North Carolina, Department of Medicine (Gastroenterology), Duke University, Durham, North Carolina.
Dawn
D
Provenzale
Department of Medicine (Epidemiology) and Cancer Center, University of New Mexico, Albuquerque, New Mexico.
Anita Y
AY
Kinney
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Population Sciences, University of Utah, Salt Lake City, Utah; National Center for Tumor Disease, German Cancer Research Center, Heidelberg, Germany.
Cornelia
C
Ulrich
Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, Utah; Department of Oncological Sciences, University of Utah, Salt Lake City, Utah.
Randall W
RW
Burt
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003113:Colonoscopy / Q000706:statistics & numerical data*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000401:mortality*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D016019:Survival Analysis; D014589:Utah / Q000453:epidemiology
Colon Cancer; Detection; Endoscopy; Neoplasm; Prevention; Tumor; US