Article Test

Introduction:
Recent guidelines by the ACG, US Multi-Society Task Force, US Preventive Services Task Force and American Cancer Society are all in consensus and have lowered the starting age for CRC screening from 50 to 451, 2, adding an additional twenty million newly eligible men and women to the screening pool. While epidemiologic and modelling data support lowering the CRC screening age,3, 4 it will put pressure on the US healthcare system already strained by the COVID-19 pandemic. Pre- pandemic, CRC screening rates among those aged 50 and older were 67%.5 The pandemic largely halted screening efforts for most of 2020, and with the resumption of screening, most healthcare systems are still trying to catch up. Hence there is an unmet need to expand CRC screening capacity.

Population based approaches are needed:
In the US, colonoscopy is the most widely used modality for CRC screening.6 However, we cannot rely solely on colonoscopy screening to meet these needs. The effect of the pandemic, influx of newly screening-eligible adults 45-49 years of age, and the existing high demand for diagnostic and surveillance colonoscopies have all contributed to the currently strained colonoscopy capacity. As gastroenterologists, we should realize that fully booked endoscopy centers may not mean that individuals that are most likely to benefit are undergoing CRC screening. A broader, population health view of the screen eligible population suggests that rather than focusing on promoting screening colonoscopies for those with easy access and interest, we can achieve a greater public health benefit by identifying those who remain unscreened or not up-to-date with current screening recommendations and delivering CRC screening equitably.

Strategies to achieve higher adherence:
One strategy to promote equitable screening is to expand availability of noninvasive screening tests and offer them in a programmatic approach. Stool based testing with fecal occult blood or fecal immunochemical testing (FIT) reduces CRC incidence and mortality in clinical trials and in organized screening programs.7-10 Offering a choice of stool- based screening tests (e.g.,FIT) in randomized trials have consistently led to higher acceptance for CRC screening invitation and screening completion. Additionally, a recently passed bill has closed the loophole for Medicare beneficiaries, wherein the diagnostic colonoscopy for a positive FIT has no cost sharing, reducing the financial burden of this option. It is a common misconception that screening colonoscopy benefits everyone. The primary benefit of colonoscopy is detection of colorectal cancer and advanced neoplasia, which is found in <1% and 10% of those undergoing screening.9-11 In the 30- 50% of individuals where no cancer or polyps are found, colonoscopy does not provide any added value other than reassurance, but exposes individuals to potential risks of the preparation, anesthesia and procedure itself. In contrast, a non- invasive screening test can help with risk stratification, by identifying individuals who are more likely to have advanced polyps and cancer and reduce the harmful risks from colonoscopy.

Improving adherence increases colonoscopy volume over time:
Many US gastroenterologists have resisted efforts to increase FIT screening out of concern that people will opt for FIT instead of colonoscopy, foregoing colonoscopy which they feel is superior to FIT. It’s important to realize that the addition of these tests will not reduce the demand for colonoscopy but likely increase it over time, and shift the indication to more diagnostic and surveillance exams. Consider this back-of-the-envelope calculation: Of the 100.3 million individuals in the US that are 50- 75 years old, approximately 33 million (33%) are not screened, plus 20 million added 45-49 year olds (total 55 million). If we offered them colonoscopy screening only, the uptake will be approximately 30% (ref), i.e. 15 million colonoscopies, which will require us to nearly double our current colonoscopy capacity. Most of these individuals will be screen eligible again in 10 years. However if we offered a FIT, and administered it programmatically, we may achieve 80% adherence, i.e. 40 million screened. At a positivity rate of 5%, that would require 2 million diagnostic colonoscopies. Since FIT needs to be repeated yearly, and assuming that 80% of the 40 million (excluding screened but including the newly eligible) adhere, that would generate 2 million colonoscopies every year for next 10 years, i.e. 20 million over 10 years. Not only do we achieve higher screening rates, we generate more colonoscopies, especially diagnostic ones, where yield of neoplasia is higher.

Conclusion:
With several new stool- and blood-based CRC screening tests now available or close to being available, now is the optimal time to expand our CRC screening approach and build organized screening programs using noninvasive testing for the health of our populations.

References
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11.    Shaukat A, Marsh TL, Crockett SD, et al. Low Prevalence of Screen-Detected Colorectal Cancer in an Average-Risk Population: The New Normal. Clin Gastroenterol Hepatol 2021.