Stool DNA and occult blood testing for screen detection of colorectal neoplasia.
BACKGROUND
Stool DNA testing is a new approach to colorectal cancer detection. Few data are available from the screening setting.


OBJECTIVE
To compare stool DNA and fecal blood testing for detection of screen-relevant neoplasia (curable-stage cancer, high-grade dysplasia, or adenomas >1 cm).


METHODS
Blinded, multicenter, cross-sectional study.


METHODS
Communities surrounding 22 participating academic and regional health care systems in the United States.


METHODS
4482 average-risk adults.


METHODS
Fecal blood and DNA markers. Participants collected 3 stools, smeared fecal blood test cards and used same-day shipment to a central facility. Fecal blood cards (Hemoccult and HemoccultSensa, Beckman Coulter, Fullerton, California) were tested on 3 stools and DNA assays on 1 stool per patient. Stool DNA test 1 (SDT-1) was a precommercial 23-marker assay, and a novel test (SDT-2) targeted 3 broadly informative markers. The criterion standard was colonoscopy.


RESULTS
Sensitivity for screen-relevant neoplasms was 20% by SDT-1, 11% by Hemoccult (P = 0.020), 21% by HemoccultSensa (P = 0.80); sensitivity for cancer plus high-grade dysplasia did not differ among tests. Specificity was 96% by SDT-1, compared with 98% by Hemoccult (P < 0.001) and 97% by HemoccultSensa (P = 0.20). Stool DNA test 2 detected 46% of screen-relevant neoplasms, compared with 16% by Hemoccult (P < 0.001) and 24% by HemoccultSensa (P < 0.001). Stool DNA test 2 detected 46% of adenomas 1 cm or larger, compared with 10% by Hemoccult (P < 0.001) and 17% by HemoccultSensa (P < 0.001). Among colonoscopically normal patients, the positivity rate was 16% with SDT-2, compared with 4% with Hemoccult (P = 0.010) and 5% with HemoccultSensa (P = 0.030).


CONCLUSIONS
Stool DNA test 2 was not performed on all subsets of patients without screen-relevant neoplasms. Stools were collected without preservative, which reduced detection of some DNA markers.


CONCLUSIONS
Stool DNA test 1 provides no improvement over HemoccultSensa for detection of screen-relevant neoplasms. Stool DNA test 2 detects significantly more neoplasms than does Hemoccult or HemoccultSensa, but with more positive results in colonoscopically normal patients. Higher sensitivity of SDT-2 was particularly apparent for adenomas.
Mayo Clinic, Rochester, Minnesota 55905, USA. ahlquist.david@mayo.edu
David A
DA
Ahlquist
Daniel J
DJ
Sargent
Charles L
CL
Loprinzi
Theodore R
TR
Levin
Douglas K
DK
Rex
Dennis J
DJ
Ahnen
Kandice
K
Knigge
M Peter
MP
Lance
Lawrence J
LJ
Burgart
Stanley R
SR
Hamilton
James E
JE
Allison
Michael J
MJ
Lawson
Mary E
ME
Devens
Jonathan J
JJ
Harrington
Shauna L
SL
Hillman
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics; D000328:Adult; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics; D003430:Cross-Sectional Studies; D004273:DNA, Neoplasm / Q000032:analysis*; D015340:Epidemiologic Research Design; D005243:Feces / Q000737:chemistry*; D005819:Genetic Markers; D006801:Humans; D008875:Middle Aged; D009780:Occult Blood; D011446:Prospective Studies; D012680:Sensitivity and Specificity
D004273:DNA, Neoplasm; D005819:Genetic Markers