Colonoscopy screening identifies unsuspected extracolonic malignancies

Virtual colonoscopy screening can find more asymptomatic cancers outside of the colon than within it, according to the results a large-scale study published in the journal Radiology (2010;255(1):83-8).

Perry Pickhardt, MD, professor of radiology and chief of GI Imaging at the University of Wisconsin School of Medicine & Public Health, and colleagues conducted a study to determine the detection rate and clinical outcome of unsuspected malignancies detected with virtual colonoscopy in an asymptomatic screening population.

Among the study population of 10,286 adults who had undergone colorectal cancer screening with virtual colonoscopy, unsuspected cancer was confirmed in 58 patients. Invasive colorectal cancer was found in 22 patients, and extracolonic cancer was found in 36 patients.

“Although extracolonic evaluation at screening CT colonography does carry some disadvantages, such as patient anxiety, inconvenience, or the potential for benign biopsy, our results suggest that early detection of asymptomatic extracolonic cancer represents an additional benefit of screening CT colonography that is not available with optical colonoscopy,” Dr. Pickhardt stated. “Virtual colonoscopy is an accurate, safe and convenient screening test that could potentially be a life-saving examination,” he concluded.

According to the press release announcing the findings, The American Cancer Society recommends that people at average risk for colorectal cancer begin regular colorectal cancer screening at age 50 years, but compliance with this recommendation is below 50%.