New colon cancer screening technique shows promise
A spectroscopy technique developed by Northwestern University researchers has a sensitivity high enough that it could be as--or more--successful than a colonoscopy for colon cancer screening, according to a proof-of-concept study in May issue of Cancer Research.

The technique uses low-coherence enhanced backscattering (LEBS) spectroscopy to analyze tissue samples taken from the base of the rectum. Light shines on the tissue, scatters, and bounces back to sensors in the probe. A computer analyzes the scattering pattern, looking for the "fingerprint" of carcinogenesis in the nanoarchitecture of the cells, according to the researchers.

The team, led by Vadim Backman, PhD professor of biomedical engineering at the McCormick School of Engineering and Applied Science at Northwestern University in Chicago, obtained biopsies from 219 patients undergoing colonoscopies.

The investigators found that LEBS signal parameters generally mirrored neoplasia progression from patients with no neoplasia, to 5-mm to 9-mm adenoma and to advanced adenomas. The composite LEBS marker calculated from the LEBS signal paralleled this risk status. Moreover, this was independent of CRC risk factors, benign colonic findings, or clinically unimportant lesions (diminutive adenomas, hyperplastic polyps), according to the authors.

For advanced adenomas, Backman and colleagues said the LEBS marker had a sensitivity of 100 percent, specificity of 80 percent and area under the receiver operator characteristic curve of 0.895.

"If you have a precancerous lesion in one part of the colon," Backman said, "even tissue that looks normal and is located far from the lesion or polyp will have molecular and other kinds of changes. It's the biological phenomenon called the 'field effect.' No one can detect these changes earlier than we can."

Further studies with a compatible fiber optic probe are under way for multicenter clinical validation.