If successful, the new assessment, when combined with sigmoidoscopy or other DNA-based tests, could be advantageous over more difficult and expensive techniques such as colonoscopy.
The assessment of mutations in fecal DNA offers promise for non-invasive colorectal cancer diagnosis. Most previous studies have focused on the more common lesions of the distal colon and rectum.
The new study, by Giovanni Traverso, Kenneth Kinzler, and Bert Vogelstein from Hopkins Kimmel Cancer Center, Baltimore, USA, and colleagues focused on patients with proximal cancers - tumors that should be the most difficult to detect as they are furthest from the anus.
The investigators analyzed 134 stool samples, which included 46 patients with known cancers in the proximal colon.
|94% of BAT26 alterations were identifiable by fecal DNA assessment.
Fecal DNA analysis revealed that 17 of the 134 patients had alterations to the BAT26 gene, a genetic marker for colorectal cancers.
Each of these 17 samples was derived from a patient with cancer, and no false positive results were observed in patients without cancer.
Subsequent analysis revealed that 18 of the 46 studied cancers harbored BAT26 alterations in their tumors, and that 17 of these 18 (94%) were identifiable by fecal DNA assessment.
Bert Vogelstein comments, "These results have several important implications for fecal DNA testing.
"They provide compelling evidence that mutations in stool can be used to identify patients with proximal cancers.
"The high specificity of the analysis, with zero false positives, was very encouraging."
"We hope that this approach will provide an important addition to the options available for reliable, non-invasive detection of curable colorectal cancers," he concluded.