CT colonography (CTC) is an effective, efficient test for senior-age patients with and without symptoms of colorectal cancer (CRC), according to a new study published in the American Journal of Roentgenology.
The authors reviewed CTC studies performed on senior-age patients—patients who are 65 years of age or older—from January 1994 to August 2017. Overall, looking at data from more than 41,000 patients, they found a “uniformly high” positive predictive value (PPV) of 84.3 percent for advanced neoplasia at colonoscopy for senior-age patients when using a threshold of polyps or masses 10 mm or larger. CTC sensitivity for CRC was 93 percent in senior-age patients and 92 percent in younger adults
“CTC appears to be a highly effective, efficient, and convenient colorectal test in senior-age adults, particularly when using a 10-mm lesion cutoff for colonoscopy referral,” wrote lead author Perry J. Pickhardt, MD, department of radiology at the University of Wisconsin School of Medicine & Public Health in Madison, and colleagues. “In particular, we showed an overall 12 percent referral rate to colonoscopy after CTC (which drops to 8 percent for screening populations with no symptoms), which was associated with a PPV for advanced neoplasia of more than 80 percent.”
Pickhardt and colleagues noted that the 10-mm referral threshold was “an optimal operating point” for CTC screening.
“By limiting colonoscopy referral to large CTC-detected lesions, the much more common subcentimeter polyps are intentionally left in place,” the authors wrote. “These diminutive polyps are almost never malignant, and only rarely harbor high-grade dysplasia. Only a small fraction of these subcentimeter polyps will ever progress to large adenomas, and even fewer will progress to invasive cancer, especially in the remaining lifetime of a senior-age adult. The ultimate goal of any screening test is to reduce morbidity and mortality related to CRC, not simply to detect and remove large numbers of subcentimeter polyps.”
The authors added that this research should help CMS make coverage decisions for CTC screening for Medicare beneficiaries. “CMS has yet to allow CTC screening of Medicare beneficiaries, which would require a national coverage determination or congressional legislation,” they wrote.
Michael has more than 16 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.