AGA speaks out on controversial NordICC data citing modest colonoscopy benefit for CRC
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Following publication of NordICC trial data in The New England Journal of Medicine, which found a modest benefit for colonoscopy screening in colorectal cancer, the AGA fired back, noting that colonoscopy is only effective “if it is completed.”
The controversial data, also presented at UEG Week in Vienna, reported that colonoscopies reduced the risk for colon cancer by approximately one-fifth. However, AGA stated that “the conclusions aren’t necessarily applicable to colorectal cancer screening in the U.S.”
In their study, Michael Bretthauer, MD, PhD, of the Clinical Effectiveness Research Group and department of transplantation medicine at Oslo University Hospital, and colleagues identified colorectal cancer as “an attractive target for population screening,” but noted that high-quality evidence was limited to determine which screening strategy was most cost-effective.
“A balance among benefits, harms, and cost-effectiveness of various colorectal cancer screening tests is important because colonoscopy is more invasive and burdensome for patients than fecal testing and sigmoidoscopy, and it requires more clinical resources,” they wrote.
The Nordic-European Initiative on Colorectal Cancer (NordICC) trial was a pragmatic, randomized study that aimed to characterize the effects of population-based colonoscopy screening on the risk for CRC and related death. Bretthauer and colleagues enrolled 84,585 participants (median age 59 years, 50.1% men) who had not previously undergone screening from population registries in Norway, Sweden and Poland.
Between 2009 and 2014, participants either received an invitation to undergo a single screening colonoscopy (n = 28,220) or did not receive an invitation (n = 56,365). Of those who received an invitation for screening, 42% underwent colonoscopy; by location, researchers reported 60.7%, 39.8% and 33% underwent colonoscopy, respectively.
At screening, they diagnosed CRC in 62 participants (0.5% of those who underwent screening) and detected/removed adenomas from 3,634 participants (30.7% of those who underwent screening). Subsequent polypectomy-related major bleeding occurred in 15 participants. No perforations or screening-related deaths occurred within 30 days after screening.
After a median follow-up of 10 years, the risk for CRC was 0.98% in the group invited to colonoscopy vs. 1.2% in the group not invited with a risk reduction of 18% (RR = 0.82; 95% CI, 0.7-0.93). Further analysis showed the number of patients needed to invite to prevent a single case of CRC within 10 years was 455 participants (95% CI, 270-1,429).
Risk for CRC-related death was 0.28% vs. 0.31% (RR = 0.9; 95% CI, 0.64-1.16). During follow-up, all-cause death occurred among 11.03% and 11.04% (RR = 0.99; 95% CI, 0.96-1.04). Moreover, in adjusted analyses to assess the impact of screening if all participants had actually undergone screening, CRC risk decreased from 1.22% to 0.84%, whereas the risk for CRC-related death dropped from 0.30% to 0.15%.
“Although we observed appreciable reductions in relative risks, the absolute risks of the risk of colorectal cancer and even more so of colorectal cancer–related death were lower than those in previous screening trials and lower than what we anticipated when the trial was planned,” Bretthauer and colleagues wrote. “This finding may reflect both a declining risk of colorectal cancer observed in many countries in recent years and an appreciable improvement in the prognosis of colorectal cancer owing to better treatment options.”
In response to the study, David Leiberman, MD, AGAF, chair of the American Gastroenterological Association’s Colorectal Cancer Task Force, highlighted discrepancies in the data that could be misinterpreted by patients and misrepresented by the media.
“This study shows that colonoscopy screening is effective – if it is completed,” Leiberman said in a statement. “Only 42% of patients randomized to colonoscopy completed the test. Among patients who actually got the colonoscopy, results are much more impressive in CRC prevention (31% decrease) and mortality (50% decrease).”
He also cited quality of the colonoscopy as a point of concern when attempting to apply this data to screening standards in the U.S. “In this study, many endoscopists had ADRs below the 25% benchmark. We know that low ADRs are associated with a higher risk of post-colonoscopy CRC,” he said. “If you know your adenoma detection rate, compare it to the rates of the doctors in the study.”
Additionally, although the detection and removal of precancerous polyps is critical to preventing future cancers, it is a benefit that requires a longer timeline to manifest. “If we assume that the ‘usual care’ patients had a similar rate of precancerous polyps that are not removed, it will take time before they develop CRC,” he said. “Hence differences between the two groups may increase with longer follow-up, which is planned.”
Leiberman urged providers to take control of the messaging from this study and be prepared to discuss this data with patients in a few short talking points: “Colonoscopy is effective in the U.S. population and can cut your risk of dying from CRC. Most of the patients in the Norway study skipped their colonoscopy; the test can’t prevent cancers if it isn’t done.”
Reference:
American Gastroenterological Association. Nordic CRC study: 3 things to know + talking points for patients. Available at: https://gastro.org/news/nordic-crc-study-3-things-to-know-talking-points-for-patients/?utm_medium=Social&utm_campaign=AGA-posts&utm_source=twitter. Accessed: Oct. 03, 2022.
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