Moving the needle in CRC screening: Knowing better, doing better
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When we reflect on the overall impact of colorectal cancer screening over the past two decades, we see the result of a collaboration of physicians and organizations who joined forces to work toward one of our great public health successes.
Though physicians have worked with scientists, public health professionals, professional organizations, advocacy groups and cancer survivors to make significant strides in CRC screening, this success story is still a work in progress. As pointed out in the cover story, there exist areas of disparity in screening and outcomes as well as a disturbing trend of rising incidence in younger adults.
Over the past 20-plus years, we have seen significant efforts in the area of CRC screening, such as physician education and public health messaging, innovation of new screening options and technologic advances, dedication to quality metrics, and even legislative changes that resulted in broader coverage of CRC screening by Medicare and health insurance plans. These efforts have led to an increase in CRC screening rates that along with more effective treatment options, have contributed to an overall decline in incidence and mortality rates.
We must now bring this same level of collaboration and commitment to respond to the increasing CRC burden in younger adults and the disparities that exist, as Rebecca Siegel, MPH, and colleagues have reported, especially affecting Black and Native American individuals.
Dr. Maya Angelou once said, “When you know better, do better.” As a gastroenterologist, I ask myself: How can we know better, and how can we do better specifically in the area of CRC screening and prevention? I believe we can learn from our past lessons and successes, as well as from ongoing research and development efforts on the causes of the concerning trends we see and strategies to address them.
Focused Messaging: The Best Test is the One That Gets Done
One driving force in the increase in CRC screening utilization has been, along with physician recommendation, the public health campaign to raise awareness about the lifesaving potential and importance of screening as part of our health and well-being. A few key messaging points have been and will continue to be essential. These include the preventive component of CRC screening, the need for screening before symptoms occur, and the availability of different screening options — including, for all those at average risk, the choice between one-step or two-step screening.
CRC is one of a few cancers for which screening affords us the opportunity for not only early detection but also prevention. During a colonoscopy, we can remove potentially precancerous polyps, thereby preventing those cancers. This, we believe, has contributed to the decline in CRC incidence with increased screening. Emphasizing CRC prevention in our patient and community education initiatives has been critical to increasing screening utilization.
Another important factor is the need for screening before symptoms occur. Many people believe they feel fine, so why get tested. It is essential to make people aware that polyps and early cancers often cause no symptoms, and this is why screening is done before symptoms occur.
Finally, innovations in testing have provided us additional effective screening options. Three of our main recommended screening tests for individuals at average risk now include colonoscopy, fecal immunochemistry testing (FIT) and a multitarget DNA stool test (Cologuard, Exact Sciences). While colonoscopy allows for the detection and removal of polyps, stool tests provide a less invasive approach to screening.
I believe it is important that we look at screening as a single-step vs. two-step approach where first-line screening colonoscopy is a single-step modality and the less invasive stool tests, when yielding positive results, require a follow-up colonoscopy and thus are part of a two-step approach.
Making our patients and the public aware of these important points and options will continue to be key. Ultimately, the best test is the one that gets done and gets done correctly.
‘Focusing on Quality Improves Quality’
Another area of progress that will continue to be paramount is that of quality in endoscopy. As we have worked to increase screening rates, we have also needed to ensure rigorous quality benchmarks. To address this need, the ACG and ASGE collaborated to form a work group to define quality metrics for colonoscopy and, in 2010, officially launched the GI Quality Improvement Consortium (GIQuIC), which serves as a formal benchmarking registry providing quality metrics and tools to collect and track them.
A few of these quality benchmarks for colonoscopy include endoscopic withdrawal time, cecal intubation rate and adenoma detection rate. A significant lesson learned from the GIQuIC experience is the strong influence of the “Hawthorne effect” on ADR. Results suggest that, just by knowing that our ADRs are being evaluated, we endoscopists tend to generate higher ADRs. Focusing on quality improves quality. Currently, the GIQuiC system has more than 4,400 physicians registered, with quality metrics for more than 15 million colonoscopies.
We have also seen advances in technology and technique that contribute to the quality of the procedure. Our ability to detect and remove polyps is dependent on our ability to view them. To this end, we have seen several innovations designed to enhance visualization of the lining of the colon. Devices that attach to the colonoscope — such as cap, cuff or balloon enhancements — have been shown to improve visualization of polyps, especially behind colonic folds, and continue to be evaluated. Artificial intelligence has shown promise and is being studied for its capacity to reduce polyp miss rates, and endoscopic technique is another aspect of quality in which research has translated into advancements in the clinical setting.
To continue to increase colonoscopy quality going forward, it will be key to assess over time the need for additional quality metrics, such as potentially tracking and managing sessile polyps, and to promote training and evaluation in colonoscopy technique, particularly in the areas of withdrawal time, cecal intubation and polypectomy technique, including resection recommendations based on polyp size, type and other parameters.
Rising Incidence in Younger Adults
As noted in the cover story, while overall CRC incidence and mortality have continued to decline (although it is slowing), Siegel and colleagues report an increase in the proportion of cases among those aged young than 55 years from 11% in 1995 to 20% in 2019. We are also seeing an increase in advanced cancer diagnoses and in distal colon and rectal cancers, which may present with rectal bleeding. While most CRC still occurs in older adults, this trend is alarming and warrants our urgent attention and dedication of resources.
As indicated by George J. Chang, MD, MS, FACS, FASCRS, FSSO, Folasade P. May, MD, PhD, MPhil, and Caitlin C. Murphy, PhD, MPH, we do not yet fully understand all the causal factors. The increase in cases in younger adults could be related to multiple factors, such as aspects of our Western diet, more sedentary lifestyle, environmental toxins or even changes in our gut microbiomes. All of these factors and more are under study.
This epidemiologic research is critical and will be key to helping us understand and respond effectively to the underlying causes of the increased CRC burden in this younger age group. In the meantime, we know from existing data that lifestyle factors such as quitting smoking, limiting intake of red and processed meat, staying physically active and limiting alcohol consumption are steps we can all take to reduce our risk.
We also know that consideration of family history and genetic syndromes is important. While most CRCs occur sporadically, about 25% develop in the context of a family history and about 5% are due to known genetic mutations, including Lynch syndrome, FAP/AFAP, MAP and others. In this subset of cases, we also often see earlier onset of disease. As physicians, we need to ensure we are taking a careful personal and family history in younger adults and educating them on the importance of their family medical history and cancer risk.
We need to offer genetic counseling and earlier testing for our younger patients with a personal or family history of not only CRC or CRC polyps, but also other cancers that are part of Lynch and other genetic syndromes. In those who have a family history, screening at a younger age may be indicated and, for those with genetic syndromes, other prophylactic measures may be considered.
For individuals at average risk, the recommended screening age was lowered from 50 to 45 years by the American Cancer Society in 2018 and shortly thereafter also by the ACG and U.S. Preventive Services Task Force. However, as reported by Siegel and colleagues, thus far, screening uptake in those aged 45 to 49 years remains relatively low, representing an opportunity for more targeted, effective public health messaging for this age group. Moreover, further research may reveal whether certain subgroups may benefit from even earlier screening in the future.
Another piece of the puzzle is the diagnosis of CRC in younger adults. Too often, we hear stories of individuals ignoring their symptoms or being misdiagnosed with irritable bowel syndrome or hemorrhoids, due to younger age. While much of our past messaging has focused on screening before symptoms, we must now also include messaging for those of all ages so they know not to ignore their symptoms.
In addition, anyone presenting with related symptoms should be evaluated with CRC as part of the differential diagnosis. Any adult, of any age, who presents with rectal bleeding should undergo colonoscopic evaluation unless the source of the bleeding can be patently identified.
Racial Disparities in Screening and Outcomes
Siegel and colleagues also reported on significant racial disparities that exist in incidence, mortality and screening rates, noting that mortality rates are 46% higher in American Indian and Alaskan Native persons and 44% higher in Black men, compared with white men. Screening rates were reported as significantly lower in the Native American population.
While the causes for these disparities are not fully understood, social determinants are known to play a major role. Indeed, for many people, their zip code may have a greater impact than genetic code on their health outcomes. We must evaluate and work together on ways to better serve these individuals and communities who are most at risk. Issues of access and cultural competence in our outreach, communications and health care systems must be a priority. Support for our epidemiologists, public health and other researchers working in this area of study is critical, so we can better understand the causal factors and potential strategies to address them, whether they be in the arenas of screening, treatment, or other care.
The more we understand, the more effectively we can develop tools and adapt our systems to focus on these disparities and eliminate them. We really must do better.
New Technologies on the Horizon
An area that I believe offers great promise for transforming the field of CRC screening is the potential for a highly effective, less invasive, user-friendly test. An effective blood test, for example, would be quick, require no preparation and could be easily incorporated into a routine health visit or in the community setting. Research is currently ongoing to develop and study blood tests that would identify the presence of early CRC by evaluating circulating DNA, methylation markers, proteomics and AI. Hopefully these technologies, in addition to new innovations, can be advanced to detect precancerous lesions in the future.
Another arena of study is the use of a breath test to detect volatile organic compounds that are present in early CRC or precancerous lesions. We know that canines are able to detect with great accuracy CRC and other cancers through smell, and we may be able to do the same using technology. An advance such as the availability of an effective, quick blood or breath test could dramatically increase access to and utilization of CRC screening, with colonoscopy remaining the critically important second step to follow-up any positive findings for those at average risk.
To achieve these next steps in CRC screening, and our larger goal of eliminating CRC as the second-leading cause of cancer death in the U.S., we must strive to know more and do better. Ultimately, we need to lean into collaboration with our fellow physicians, scientists, public health professionals, advocates and others to increase our understanding of existing gaps in care and outcomes, invest in key and culturally competent public health messaging, support and integrate innovation and quality efforts, and make effective CRC screening accessible to all those for whom it is recommended.
As we know better, we must do better.
- For more information:
- Mark B. Pochapin, MD, is the Sholtz-Leeds Professor of Medicine, director of the division of gastroenterology and hepatology, and vice chair of clinical affairs for the department of medicine at NYU Grossman School of Medicine and NYU Langone Health. He can be reached at mark.pochapin@nyulangone.org.
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