Accuracy of colorectal polyp self-reports: findings from the colon cancer family registry.
BACKGROUND
Colorectal adenomas and other types of polyps are commonly used as end points or risk factors in epidemiologic studies. However, it is not known how accurately patients are able to self-report the presence or absence of adenomas following colonoscopy.


METHODS
Participants in the Colon Cancer Family Registry provided self-reports of recent colorectal cancer (CRC) screening activity, and whether or not they had ever been told they had a polyp. Positive and negative predictive values for polyp self-report were calculated by comparing medical records with self-reports from 488 participants.


RESULTS
The positive predictive value for self-reported polyp was 80.9%, and the negative predictive value was 85.8%. The predictive values did not differ by age group or sex, but participants with a previous diagnosis of CRC had a lower negative predictive value (76.2%) than participants with no personal history of CRC (89.0%; P = 0.04).


CONCLUSIONS
Predictive values for self-reports of polyps are fairly high, but researchers needing accurate polyp data should obtain medical record confirmation. Pursuing medical records on only those participants self-reporting a polyp could result in an underestimation of the polyp prevalence in a study population.
Madlensky
Lisa
L
Moores UCSD Cancer Center, 3855 Health Sciences Drive, MC0901, La Jolla, CA 92093-0901, USA. lmadlensky@ucsd.edu
Daftary
Darshana
D
Burnett
Terrilea
T
Harmon
Patricia
P
Jenkins
Mark
M
Maskiell
Judi
J
Nigon
Sandra
S
Phillips
Kerry
K
Templeton
Allyson
A
Limburg
Paul J
PJ
Haile
Robert W
RW
Potter
John D
JD
Gallinger
Steven
S
Baron
John A
JA
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003111:Colonic Polyps / Q000150:complications; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000209:etiology; D003625:Data Collection; D005260:Female; D006801:Humans; D007256:Information Systems; D008297:Male; D008403:Mass Screening / Q000379:methods; D008487:Medical History Taking / Q000379:methods; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D011795:Surveys and Questionnaires