CT colonography accurately screens for colorectal cancer

Colorectal cancer is the second leading cause of cancer deaths in the US, despite the fact that it is a largely preventable condition through screening for benign growths. The American Cancer Society recommends that people who are at average risk begin screening at age 50, but fewer than half of those individuals comply. Many people resist because of the discomfort caused by the standard optical colonoscopy procedure, which is invasive.

As presented in the November issue of Radiology, Dr. Perry J. Pickhardt, from the department of radiology at the University of Wisconsin Medical School in Madison, and his colleagues found that 3-D CT colonography, also known as virtual colonoscopy, is an accurate, noninvasive screening method for colorectal cancer.

The image depicts a large growth revealed by CT colonography. Reprinted with permission of Radiology.

Over a one-year period, the researchers performed CT on 1110 patients. Patients with growths larger than 10 mm were referred for same-day optical colonoscopy, and those who had medium-size (6 to 9 mm) lesions had the option of optical colonoscopy or CT colonography surveillance. Large growths were identified in 43 patients and medium-size lesions were identified in 77 patients, 31 of whom chose CT colonography surveillance. Seventy-one patients underwent subsequent optical colonoscopy, and lesions were detected in 65 of them — showing a substantial agreement with the CT colonography method.

The researchers believe the results prove that CT colonography is an effective method for detecting colorectal cancer and may help increase screening in patients who resist the standard optical colonoscopy test.