Despite tight limitations on Medicare reimbursement, virtual colonoscopy (VC) is being used appropriately for colorectal cancer screening, according to a new study published online April 5 in the Journal of General Internal Medicine that examined more than 170,000 patient records.
Results from the Medicare claims database analysis showed that the vast majority of patients who received virtual colonoscopy (also known as CT colonography or CTC) were likely to have been referred after incomplete optical colonoscopy, and were therefore considered appropriate candidates for CTC even under strict eligibility rules in place since 2009. Nearly half (47%) of the patients studied who underwent CTC following incomplete optical colonoscopy did so on the same day as optical colonoscopy, sparing the patients the extra burden of preparing for the procedure twice, reported the study team from the Hospital of the University of Pennsylvania in Philadelphia.
"The reasons patients were being referred to CTC was incomplete optical colonoscopy, which was far and away the most common reason, as well as patients who were on anticoagulation therapy, or patients who had a sedation risk," lead author Dr. Hanna Zafar said in an interview with AuntMinnie.com. "We also looked at the people who shouldn't be receiving CTC, including patients with inflammatory bowel disease ... and what we found that was reassuring was that very few of those patients are receiving CT colonography."
Considering that bowel preparation is known to discourage many patients from seeking screening, offering same-day CTC could improve completion of screening by eliminating the need for an additional bowel prep -- and the study shows that same-day CTC is the norm, Zafar said.
"Of the patients who were referred for incomplete optical colonoscopy, half of them were referred for same-day CTC," Zafar said. "That's really exciting, because we all know that the bowel preparation is the biggest deterrent to any patient getting colorectal cancer screening, and I like to think it would have caught some patients who would have been unable to complete a second bowel preparation."
Zafar and her colleagues Jianing Yang, Michael Harhay, Dr. Anna Lev-Toaff, and Dr. Katrina Armstrong focused on patient patterns after the 2009 change went into effect, examining records for 10,538 asymptomatic older individuals who underwent CTC and comparing them 9:1 with a matched cohort of 160,113 individuals who underwent optical colonoscopy. One-third of the subjects undergoing CTC had no history of incomplete optical colonoscopy, but instead presented with other medically appropriate indications for screening CTC, including elevated risk of bleeding or complications with sedation procedure typically used for optical colonoscopy.
CTC performed on older, wealthier, whiter population
The results showed that virtual colonoscopy utilization was higher among women, patients older than 65 years, white patients, and those with household income greater than 75 % of the median (p = 0.001). Patients with relatively appropriate clinical indications for screening CTC were more likely to undergo CTC versus optical colonoscopy, including the following:
- Patients with presumed incomplete colonoscopy (odds ratio [OR]: 80.7; 95% confidence index [CI]: 76.01-85.63)
- Risks associated with sedation (OR: 1.11, 95% CI: 1.05-1.17).
- Chronic anticoagulation risk (OR: 1.46, 95% CI: 1.38-1.54) after adjusting for patient characteristics and known clinical indications.
Conversely, the group noted, patients at higher risk from CTC were unlikely to undergo the exam (OR: 0.4, 95% CI: 0.37-0.42). Overall 83% of symptomatic patients referred to CTC had at least one clinical indication indicating that CTC was appropriate.
The researchers said they could not determine how many of the CTC-screened individuals would have foregone screening without the option of CTC, but the results suggest that the imaging exam may have expanded the pool of individuals screened -- a key goal of the government and screening proponents -- rather than just replacing the choice of exam for screening they would have received anyway.
Previous research has suggested that nearly one-third of patients would not have undergone conventional optical colonoscopy if CTC had not been available. More research is needed in this area, since approximately 40% to 50% of Medicare patients do not undergo any colon cancer screening, Zafar said.
More education may boost minority, male participation
CTC utilization was lower among nonwhite patients, for reasons that are unclear, Zafar said. The decreased utilization may be due to their reduced access to imaging, or to a generally lower rate of colorectal cancer screening. This group would benefit disproportionately from the implementation of widespread CTC screening due to minorities' traditional low rates of participation, and the higher incidence of colorectal cancer among blacks, she added.
Dr. Judy Yee from the University of California, San Francisco (UCSF), who was not involved in the study, suggested that less contact with the healthcare system in general and less education about advanced screening techniques in particular may have been important causes of reduced participation rates among women and minorities. The scenario of CTC potentially exacerbating disparities that already exist in CTC utilization, as suggested in the paper, is unlikely, she said.
"They looked at a large number of screening patients, and they found some interesting trends, including the fact that patients who came in for CTC were more likely to be women, older patients -- what we call the 'older elderly' above age 65 -- and racially were more white patients who had higher household incomes," said Yee, who is chief of radiology at the San Francisco Veterans Affairs Medical Center and vice chair of radiology at UCSF. "I think this highlights that women who underwent breast cancer screening and cervical cancer screening were more aware of colorectal cancer screening, and in particular know about a less invasive test for screening. This may be related to the fact that higher income households were better educated and have learned more about CTC. So I think it means we have to improve our efforts to educate people about the availability of CTC as a less invasive test -- particularly among minority patients and lower income groups."
CTC following incomplete colonoscopy is covered by most private insurers and the U.S. Centers for Medicare and Medicaid Services (CMS). Unfortunately, many other indications, including the use of CTC in asymptomatic individuals, are not covered. In May 2009, CMS declined to issue a national coverage decision to reimburse physicians for virtual colonoscopy procedures in part due to concerns over how it feared the technique was being used in elderly populations that might not benefit from colorectal cancer screening.
The American Cancer Society and American College of Radiology, among other medical societies, opposed the 2009 coverage limitations, and support increased access to colorectal screening through CTC. The ACR's colon cancer committee is working with a wide array of stakeholders such as CMS, private payors, and the U.S. Preventive Services Task Force (USPSTF) to overcome any remaining objections to widespread colorectal cancer screening with virtual colonoscopy, and remains hopeful of its prospects in the coming years.
"I think that CTC definitely has a role as a primary screening method," Zafar said. "About 30% of the patients who received CTC had not received prior optical colonoscopy. ... We want to do a better job of reaching that 40% of the population that is never getting screened, and I think what this paper suggests is that some of the people who received CTC would never have received optical colonoscopy, and that's an exciting finding because it means we're tapping into that unscreened cohort."
The data from this study is encouraging in terms of what the USPSTF, which is coordinating its efforts with CMS, is likely to conclude following its re-evaluation of CTC beginning this fall, Yee said. Another paper due out in July (Yee et al) will review what's been done to satisfy the government's request for additional data on CTC, and conclude that "the time has arrived for national reimbursement of screening CTC," she said.
She cautioned, however, that the USPSTF's reassessment will be a long process that could take 18 months to reach a conclusion, though CMS might reach a positive conclusion concurrently if the data seem strong enough.
