Exfoliated colonocyte DNA levels and clinical features in the diagnosis of colorectal cancer: a cohort study in patients referred for investigation.

Abstract

AIM:

Selection of patients for investigation of suspected colorectal cancer is difficult. One possible improvement may be to measure DNA isolated from exfoliated cells collected from the rectum.

METHOD:

This was a cohort study in a surgical clinic. Participants were aged ≥40 years and referred for investigation of suspected colorectal cancer. Exclusion criteria were inflammatory bowel disease, previous gastrointestinal malignancy, or recent investigation. A sample of the mucocellular layer of the rectum was taken with an adapted proctoscope (the Colonix system). Haemoglobin, mean cell volume, ferritin, carcino-embryonic antigen and faecal occult bloods were tested. Analysis was by logistic regression.

RESULTS:

Participation was offered to 828 patients, of whom 717 completed the investigations. Three were lost to follow up. Seventy-two (10%) had colorectal cancer. Exfoliated cell DNA was higher (P<0.001) in cancer (median 5.4 μg/ml [inter-quartile range 1.8,12]) compared with those without cancer (2.0 μg/ml [IQR 0.78,5.5]). Seven variables were independently associated with cancer, including age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.02,1.08; P<0.001) DNA (OR, 1.05; CI, 1.01,3.6; P=0.01), mean cell volume (OR, 0.93; CI, 0.89,0.97; P=0.001), carcino-embryonic antigen 1.02 per μg/l (CI, 1.00,1.04; P=0.02), male sex (OR, 2.0; CI, 1.1,3.6; P=0.02), rectal bleeding (OR, 2.4; CI, 1.3,4.5; P=0.007) and positive faecal occult blood (OR, 6.7; CI, 3.4, 13; P<0.001). The area under the receiver-operating characteristic curve for the DNA score was 0.65 (0.58-0.72) and for the seven variable model 0.88 (CI, 0.84-0.92).

CONCLUSION:

Quantification of exfoliated DNA from rectal cellular material has promise in the diagnosis of colorectal cancer, but this requires confirmation in a larger study.

• Authors: Lalitha Mahadavan, Alexandre Loktionov, Ian R Daniels, Angela Shore, Diane Cotter, Andrew H Llewelyn, William Hamilton
• Journal: Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland (Colorectal Dis) Vol. 14 Issue 3 Pg. 306-13 (Mar 2012) ISSN: 1463-1318 [Electronic] England
• PMID: 21689307 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2011 The Authors. Colorectal Disease © 2011 The Association of Coloproctology of Great Britain and Ireland.

Chemical References

• DNA, Neoplasm

Topics

• Adult
• Aged
• Aged, 80 and over
• Cohort Studies
• Colon (pathology)
• Colorectal Neoplasms (diagnosis, genetics)
• DNA, Neoplasm (analysis)
• Female
• Humans
• Intestinal Mucosa (pathology)
• Logistic Models
• Male
• Middle Aged
• Multivariate Analysis
• Proctoscopy
• ROC Curve
• Rectum (pathology)