Biopsy and polypectomy frequently are performed for lesions that carry a low risk of malignant transformation in the colon.
Elastic scattering spectroscopy is a novel optical biopsy technique that can distinguish normal from abnormal tissue in vivo, without the need to remove tissue.
Dr Dhar and colleagues from England assessed the diagnostic potential of elastic scattering spectroscopy in the colon.
The researchers assessed whether the technique differentiates normal colonic mucosa, chronic colitis, and adenocarcinoma.
The research team also evaluated whether it differentiates hyperplastic polyps, and adenomatous polyps with dysplasia.
Elastic scattering spectroscopy spectra were obtained from 138 sites in 45 patients at colonoscopy.
|The specificity of differentiating adenomas from hyperplastic polyps was 84%|
These were then compared with conventional biopsy specimens taken from the same site.
The team also took specimens from normal colonic mucosa, hyperplastic polyps, adenomatous polyps, chronic colitis, and colon cancer.
Spectral analysis was carried out with a validated computerized model that used principal component analysis followed by linear discriminant analysis.
Cross validation was carried out by using 60% of the data as a 'training set' and the remaining 40% of the data as a 'test set'.
A total of 483 spectra were analyzed.
Of these, the team noted that 290 were normal, 19 were hyperplastic, 69 were adenomatous polyps, 74 had chronic colitis, and 31 had colorectal cancer.
The sensitivity and the specificity of differentiating adenomas from hyperplastic polyps was 84%.
The researchers found that the sensitivity and specificity for cancer from adenomatous polyps was 80% and 75%, respectively.
For colitis from normal tissue, sensitivity and specificity was 77% and 82%, respectively.
The team observed that for dysplastic mucosa from colitis, the sensitivity and specificity was 85% and 88%, respectively.
Dr Dhar's team concludes, “Elastic scattering spectroscopy holds promise for differentiating colonic lesions with good accuracy.”
“Therefore, it is a potentially useful tool to make an instantaneous diagnosis during colonoscopy.”
“It could prove a valuable aid for targeting biopsies in dysplasia surveillance in inflammatory bowel disease and for deciding which small polyps should be removed.”