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Wallin U.,Akademiska Sjukhuset | Gunnarsson U.,Karolinska Institutet | Glimelius B.,Uppsala University | Glimelius B.,Karolinska Institutet | And 2 more authors.
International Journal of Colorectal Disease | Year: 2010

The objective was to evaluate a new method for DNA sampling from the rectal mucosa for the detection of colorectal cancer or any clinically significant pathology in the colon and rectum. Methods: This prospective cohort study included patients scheduled for colonoscopy (group 1, n=185) or colonic resection because of suspected colorectal cancer (group 2, n=62). A test instrument with a balloon-holding end was introduced through a proctoscope into the rectum to collect exfoliated cells, from which DNA was isolated and quantified. Results: The detection of colorectal cancer in group 1 showed a sensitivity for the DNA cut-off levels 1.5, 2, and 2.5 μg/ml of 100%, 80%, and 60%, and a specificity of 37%, 46%, and 56%, respectively. In group 2, for the same cut-off levels, the sensitivity was 73%, 61%, and 55%, and the specificity was 67%, 67%, and 67%, respectively. Conclusions: This novel technique is a safe and easy way of collecting DNA from the rectal mucosa. The sensitivity and specificity of the test were too low to be acceptable for a screening test. The low sensitivity and specificity in this study could be explained by the diversity within the study groups as many patients presented with long-term history of colorectal disease and surgical interventions in the past. © 2010 Springer-Verlag.

Mahadavan L.,Royal Devon and Exeter NHS Foundation Trust | Mahadavan L.,University of Exeter | Loktionov A.,Colonix Medical Ltd | Daniels I.R.,Royal Devon and Exeter NHS Foundation Trust | And 5 more authors.
Colorectal Disease | Year: 2012

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 ≥40years 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 5.4μg/ml [inter-quartile range 1.8,12]) compared with those without cancer (2.0μg/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. © 2011 The Authors. Colorectal Disease © 2011 The Association of Coloproctology of Great Britain and Ireland.

Loktionov A.,Colonix Medical Ltd | Loktionov A.,Colonix Medical Ltd | Ferrett C.G.,John Radcliffe Hospital | Gibson J.J.S.,Honiton Hospital | And 7 more authors.
International Journal of Cancer | Year: 2010

This pilot study aimed to assess an original test based on the analysis of exfoliated colonocytes as a new approach to colorectal cancer (CRC) detection. DNA was isolated from exfoliated cells collected from the surface of the rectal mucosa by a standardized minimally invasive procedure in a case-control trial involving 66 patients with CRC diagnosis and 110 healthy volunteers (age 50-70). PicoGreen staining and quantitative real-time PCR (QRTPCR) were used for DNA quantification. Mean DNA scores in μg/ml obtained for the control and cancer groups were 2.1 (95% Cl 1.7-2.5) and 9.0 (Cl 6.7-11.2) respectively (p < 0.001) for PicoGreen and 0.8 (Cl 0.6-0.9) and 3.8 (Cl 1.9-5.7) respectively (p = 0.003) for QRTPCR. The PicoGreen assay better detected CRC presence. At DNA score cut-off point of 2.5 μg/ml this assay gave sensitivities of 77.8% (Cl 52.4-93.6) for proximal tumours, 91.4% (Cl 76.9-98.2) for distal CRC and 86.8% (Cl 74.7-94.5) for all CRC with specificity at 74.0% (Cl 64.0-82.4). Increasing the cut-off point to 5.0 μg/ml resulted in sensitivities of 38.9% (Cl 17.3-64.3) for proximal tumours, 71.4% (Cl 53.7-85.4) for distal CRC and 60.4% (Cl 46.0-73.5) for all CRC. Specificity for this cut-off point Increased to 94.8% (Cl 88.3-98.3). The new procedure of exfoliated cell collection from the surface of the rectal mucosa is a simple, safe and well-tolerated technique providing high quality cells. These early results suggest that exfoliated cell collection in combination with DNA quantification can potentially be employed as a tool for CRC early detection. © 2009 UICC.

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