The 411 on CTC
By Keith Loria
Radiology Today
Vol. 20 No. 1 P. 20

Are you aware of the current regulatory and clinical issues associated with this critical colon screening tool?

Colorectal cancer is the second leading cause of death from cancers that affect men and women in the United States, with more than 50,000 Americans expected to die from the disease in 2018 alone. Yet, at least one-third of those 45 and older who should be screened for colorectal cancer choose not to be tested.

Doug Owens, MD, MS, vice chairperson of the US Preventive Services Task Force (USPSTF), says the organization strongly recommends screening adults in this age group—evidence shows it reduces the risk of dying from the disease. He adds that those older than 75 should weigh their options.

"For adults ages 76 to 85, the decision to screen for colorectal cancer should be an individual one, based on the patient's overall health and prior screening history," he says. "Screening intervals vary based on the method used, so patients and doctors should decide together which option is best for each individual." With multiple screening options having demonstrated the ability to reduce the risk of dying from the disease, patients have little excuse not to be screened.

CT colonography (CTC) is one effective option. In fact, the Prevent Cancer Foundation, the ACR, and other minority, patient, and provider health care groups have been calling on Congress to pass the CT Colonography Screening for Colorectal Cancer Act (HR 1298), which would provide Medicare coverage for screening with CTC.

"Medicare-covered access to CTC may help increase colorectal cancer screening rates by attracting those who do not wish to undergo a colonoscopy and would otherwise not be tested," says Carolyn Aldigé, founder and CEO of the Prevent Cancer Foundation. "Colorectal cancer screening saves lives. According to a major study, Medicare coverage of CTC would cut costs of colorectal cancer screenings by 29% and save Medicare up to $1.7 billion per screening cycle."

Advocating for Insurance
HR 1298, introduced by Congressmen Brad Wenstrup (R-OH) and Danny Davis (D-IL), and S 3465, introduced by Senators Jim Inhofe (R-OK) and Bernie Sanders (I-VT), require Medicare coverage of CTC. HR 1298 currently has 88 cosponsors, while S 3465 was only recently introduced.

Currently, 37 states require insurance policies to cover virtual colonoscopy, and insurers that are part of federal exchanges are required by the Affordable Care Act (ACA) to cover the exam with no copay. CIGNA, Aetna, UnitedHealthcare, Anthem Blue Cross Blue Shield, and others cover the test irrespective of ACA requirements. However, Medicare refuses to cover seniors for this American Cancer Society–recommended exam.

Aldigé explains that the Centers for Medicare & Medicaid Services (CMS) does not cover CTC because it believes it to be ineffective, but research shows that CTC is as accurate as a standard colonoscopy for most people. Therefore, the only way to regulate Medicare coverage of CTC is for CMS to change its policy or for Congress to pass a law requiring CMS to include CTC in its coverage.

"Colorectal cancer screening is essential to the prevention and early detection of colorectal cancer," Aldigé says. "With screening, health care professionals can identify and remove precancerous polyps before they develop into cancer or detect cancer at early stages, when successful treatment is more likely."

She says progress has been made on the state level, which could potentially impact Congress' or CMS' decision to add CTC into Medicare coverage.

"The Prevent Cancer Foundation and other patient and advocacy groups continue to engage with CMS, encouraging them to update their recommendations to include CTC," Aldigé says. "We are vocal about the fact that lifesaving screening needs to be accessible for all. We continue to put pressure on Congress. It is worth fighting for, because its use has been demonstrated to increase overall screening rates."

Medicare, which does approve CTC, has CTC-1 codes for reimbursement of diagnostic CTC. Therefore, a patient who is symptomatic qualifies for a diagnostic CTC that is already covered by Medicare. It remains unclear, however, why Medicare continues to reimburse only for diagnostic and not for screening CTC.

Judy Yee, MD, chair of the ACR Colon Cancer Committee, says in its initial denial, CMS named three reasons. One was that it wanted more information on performance of the test in a Medicare-age patient population—65 and above—though she says there are multiple studies already published showing CTC is as effective in the older patient cohort.

"Number two is that they wanted more information on the effects of radiation. The radiation has continued to decrease for CTC to the point now where it's at the level of annual background dose, so that's really not a concern at this point. In fact, I think that's something that, in some of our discussions with CMS, is less of a concern," Yee says. "The third was what to do with extracolonic findings. That's something that the American College of Radiology has helped to deal with, in developing more standardized guidelines on management of these incidental extracolonic findings."

In Yee's opinion, CMS is stuck on the fact that there are some studies that show a relatively high rate of incidental findings, but, at the same time, they have ignored the fact that these same studies show that the percentage of significant extracolonic findings is dramatically lower.

"There are many times when these extracolonic findings that are made on CTC can actually save a patient's life," she says. "Some of these findings include extracolonic malignancies. So the patient comes in and may be asymptomatic, and we find a cancer, such as a kidney cancer. That could save a life but not because we discovered a colorectal cancer. That is something that should not be ignored. Other extracolonic findings that we could make on CTC include double aortic aneurysms."

Clinical Pros and Cons
There are benefits and drawbacks to CTC when compared with colonoscopy, though CTC is widely considered to be as sensitive and specific as colonoscopy.

"The benefit is that it is noninvasive and does not require sedation, so less time is diverted from other activities," Aldigé says. "The drawback is that if a polyp is identified, the individual will have to go through the prep for a second time and have a traditional colonoscopy to remove the polyp."

However, Yee says, less than 10% of those screened need cancers or polyps removed, and facilities that offer CTC generally work well with their gastroenterology colleagues to ensure that those follow-up procedures are carried out in an efficient manner.

"CTC is generally less expensive than standard colonoscopy, and the small number of patients needing cancer and polyp removal still render CTC to be a cost-effective exam," she says.

Yee notes that CTC is a structural test; therefore, it can pinpoint the location of and identify a finding, unlike the fecal immunochemical test, which basically looks for blood in the stool. CTC has other benefits as well, she adds.

"With the CTC, we actually see the entire colon. This is in contrast to flexible sigmoidoscopy, which sees only the very bottommost portion of the colon," Yee says. "Another advantage of CTC is that, compared to traditional colonoscopy, you do not need to undergo sedation. Patients can drive themselves to the CTC and then drive home themselves and return to normal daily activity."

CTC has a much lower perforation risk compared with colonoscopy; because physicians aren't introducing a six-foot-long scope into the colon, there's much less of a chance of poking a hole into the colon wall.

"There's also a decreased chance of causing a significant infection or significant bleeding compared with colonoscopy," Yee says. "I think that from the perspective of major organizations that include CTC as a valid screening option, CTC is a valid colorectal cancer screening tool. It needs to be an option for those patients who may not want to undergo the colonoscopy or who may be safer undergoing the CTC."

A limitation of CTC is that it requires colonic cleansing, so the patient still must take a laxative the day before the test, Yee says.

Screening Recommendations
It is important for people to take advantage of all validated methods of screening according to their recommended guidelines. In many cases, precancerous lesions can be identified and removed, avoiding cancer altogether. In other cases, cancer can be detected at an early stage, leading to a more successful treatment outcome.

According to Owens, different screening tests have various strengths and limitations, but none reviewed by the USPSTF has proven more effective than another.

"While the potential benefits and harms of screening tests vary, CTC may be attractive to some patients because it is a less invasive option," he says. "Patients and doctors should decide together which screening method is best for each individual. However, patients should be aware that if CTC is positive, they would then need to undergo a colonoscopy."

Colonoscopy requires less frequent screening—every 10 years vs every five for CTC—and allows for screening and follow-up of positive findings to be performed during the same examination, minimizing the burden on patients.

"It is also worth noting that, although the risk of immediate harms from CTC is low, more research is needed on the potential harms that could be caused by low-dose radiation or detection of extracolonic findings—also known as the diagnosis of abnormalities outside of the colon and rectum," Owens says.

The USPSTF recommends colorectal cancer screenings for people with average risk starting at age 50. However, the American Cancer Society recently released a new recommendation, which the Prevent Cancer Foundation endorses, for screenings to begin at age 45.

"With colorectal cancer on the rise in younger people, screenings at an earlier age can help prevent colorectal cancer or detect it earlier, when successful treatment is more likely," Aldigé says.

Additionally, those at increased risk for colorectal cancer may need to begin screening earlier or be screened more frequently. Risk factors include smoking, being overweight or obese, drinking alcohol in excess, eating a lot of red or processed meat, and having a personal or family history of colorectal cancer, colorectal polyps, or inflammatory bowel disease, such as ulcerative colitis and Crohn's disease.

Support continues to come in for CTC, including from the FDA, which recently convened a specific panel to examine its safety and efficacy. There was overwhelming support that it should be a screening option.

"I think this is an exciting time and things will change," Yee says. "Medicare needs to cover CTC and help physicians save more lives."

— Keith Loria is a freelance writer based in Oakton, Virginia.