Cancer guidelines add CTC as alternative
A newly released guideline on colorectal cancer screening offers recommendations for various alternatives for colorectal cancer detection, including — for the first time — radiological examination by CT colonography (CTC), also known as virtual colonoscopy.
For CTC, the new guideline reflects that the risk for patients whose largest polyps are smaller than 5 mm is low, but for polyps over 5 mm in size, a follow-up by colonoscopy is recommended.
The guidelines also recommend barium enema as an alternative, and they state a strong preference for screening tests that can prevent colorectal cancer.
Several tests are among the recommended alternatives including stool tests that detect colorectal cancer but not its precursor, colon polyps, and structural examinations of the colon by endoscopic procedures such as flexible sigmoidoscopy and colonoscopy. The new guideline recognizes that for flexible sigmoidoscopy and barium enema, as well as CTC, a follow-up colonoscopy will be required for suspicious polyps.
Based on a review of the historic and recent evidence, the following tests were deemed acceptable options for the early detection of colorectal cancer and adenomatous polyps for asymptomatic adults aged 50 years and older:
- flexible sigmoidoscopy every five years;
- colonoscopy every 10 years;
- double contrast barium enema (DCBE) every five years;
- CT colonography (CTC) every five years.
"The addition of these new technologies can potentially encourage many more people to choose to be screened for colorectal cancer," said Arl Van Moore, MD, FACR, chair of the American College of Radiology Board of Chancellors, in a prepared statement. "This could result in early detection of the disease for more patients, increasing the chance of successful treatment and potentially reduce colorectal cancer deaths nationwide."
The guidelines were developed by the American Cancer Society, the American College of Radiology, and the U.S. Multi-Society Task Force on Colorectal Cancer, which includes representatives from the American College of Gastroenterology (ACG), the American Society for Gastrointestinal Endoscopy (ASGE), and American Gastroenterological Association.
Amy E. Foxx-Orenstein, DO, FACG, president of the ACG, said in statement, "What distinguishes these new guidelines is an emphasis on the importance and value of preventing colorectal cancer, which GI physicians applaud."
Fifty percent of Americans who should be getting screening for colorectal cancer are not, said Grace H. Elta, MD, FASGE, president of the ASGE, in a statement. "The data show that screening saves lives and efforts to increase colon cancer awareness and screening will help patients through earlier detection," Elta says.
Representatives of the ASGE and the ACG say that the guideline's stated preference for tests that prevent colorectal cancer supports the groups' longstanding positions that colonoscopy is the preferred screening strategy for colorectal cancer. They point to its sensitivity in detecting polyps and its potential for removing them and breaking the sequence of polyp to cancer in a single diagnostic and therapeutic intervention.
There are unresolved questions about radiation risks and identifying small or flat polyps, according to the statement from the ACG. CTC may be useful for those who refuse, who cannot undergo, or who have failed prior colonoscopy, the college said.
Foxx-Orenstein said, "All of us on the front lines of battling colorectal cancer welcome this thorough review of the evidence regarding all the various screening modalities. While the evidence suggests that there are some limitations to all of the tests, the college sees significant strengths in the proven benefits of visualizing pre-cancerous growths and removing them in a single examination during colonoscopy."
Each year nearly 150,000 people are diagnosed with colon cancer, and almost 50,000 die from the disease annually in the United States. Colorectal cancer is the third most commonly diagnosed cancer in men and women and the second leading cause of cancer-related deaths in the United States. The five-year relative survival rate for people whose colon cancer is treated in an early stage is greater than 90%; however, only 39% of colon cancers are found at that early stage. Once the cancer has spread to nearby organs or lymph nodes, the five-year relative survival rate decreases dramatically.
The full guideline can be viewed at caonline.amcancersoc.org/. Click on "ACS Guidelines."
A newly released guideline on colorectal cancer screening offers recommendations for various alternatives for colorectal cancer detection, including — for the first time — radiological examination by CT colonography (CTC), also known as virtual colonoscopy.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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