Cancer: PET/CT may detect colonic pathology

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PET/CT has been shown to be a promising tool for detecting colonic pathology, according to a M.D. Anderson Cancer Center study published online Feb. 8 in Cancer.

William A. Ross, MD, associate professor of the department of gastroenterology, hepatology & nutrition at the University of Texas M. D. Anderson Cancer Center in Houston, and colleagues reviewed the records for all patients who underwent PET/CT and colonoscopy at their institution.

The investigators divided the patients into two groups: Group A had 58 patients with incidental colonic 18F-FDG activity on PET and Group B had 272 patients with no uptake. Patients with history of colonic malignancy or colon surgery were excluded from the study.

“In Group A, 65 percent of patients had pathologic findings detected on colonoscopy that corresponded to the site of PET activity. Standardized uptake value (SUV) readings were not helpful in distinguishing true-positives from false-positives,” wrote Ross and colleagues.

The investigators found that 11.8 percent of the Group B patients had significant colonic findings and that lesions not detected by PET/CT included four colon cancers, seven advanced adenomas, and 10 patients with colonic lymphoma.

“Overall, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT for detecting significant pathology were 53 percent, 93 percent, 65 percent, 89 percent, and 85 percent, respectively,” wrote the authors.

The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT were 72 percent, 90 percent, 45 percent, 96 percent, and 88 percent, respectively for detecting colon cancer and adenomas 10 mm or more, noted Ross and colleagues.

“Incidental colonic activity detected by PET/CT warrants further evaluation with colonoscopy. However, negative PET/CT does not rule out significant colonic pathology including colon cancer, advanced adenomas, or lymphoma,” concluded the authors.