Progress in Screening: The Key To Lower Colorectal Cancer Mortality

Reading time: 6 minutes

Kate Gavaghan

Colorectal cancer (CRC) is the third most common form of cancer in the US, and the second most common cause of cancer death. It’s estimated that in 2020, approximately 148,000 individuals were diagnosed with CRC and about 53,200 died. 

The good news is that the incidence of CRC has actually declined dramatically over the past two decades among adults over 50. We can attribute this drop to screening that detects and removes polyps before they become cancerous. The bad news is that screening rates are still far too low, hovering around 66% overall. Among Medicaid enrollees and rural or ethnically diverse populations, screening rates are as low as  35-50%. We’re missing the opportunity to stop thousands of cancer cases before they start. However, some recent progress in screening protocols could help. 

Source: CA: A Cancer Journal for Clinicians. Trends in Colonoscopy Prevalence (2000 to 2018) and Colorectal Cancer Incidence Rates (2000 to 2016), Adults ≥50 Years, United States. Prevalence was based on colonoscopy within the past 10 years of the survey date. Incidence rates exclude the appendix and are age-adjusted to the 2000 US standard population and adjusted for reporting delays. Source: Colonoscopy prevalence: National Health Interview Survey, 2019; Incidence: NAACCR, 2019.

Lower Age Recommendations

Epidemiologists have known for some time that CRC is on the rise among young people. Between 2007 and 2018, CRC rates increased 1.3% each year among those under 50. In 2018, the American Cancer Society began recommending that screening begin at age 45, rather than 50. And a few months ago the US Preventative Service Task Force (USPSTF)–a panel of federally appointed medical experts who determine which screenings are covered by insurance under the Affordable Care Act–finally concurred. While this new policy is still in the “draft” stage, it will likely be finalized. Health experts expect tens of thousands of additional cancers to be prevented or treated early as a result of this change.

Better At-Home Testing Kits

For many of us, CRC screening means one thing–a colonoscopy. Yet, data show that only two-thirds of Americans aged 50 to 75 undergo this procedure. Break the data down even more and we see rates as low as 35-50% for rural and lower-income populations. For those between 50 and 54, the screening rate is only about 50%. 

Many factors drive these rates down: lack of insurance, job obligations, logistics, even convenience. The colonoscopy itself typically takes a day out of one’s schedule. Many people are also put off by the period of fasting/laxatives/copious bowel movements the day before, and recovering from anesthesia after the procedure. Research shows this can be more of an issue for younger and/or working people–the very demographic where CRC is on the rise.

Greater use of simple, at-home stool tests–already the screening tool more commonly used throughout Europe–could boost US screening rates. To use an at-home test, individuals collect and mail a stool sample back to a lab. Some kits detect small amounts of hemoglobin, the protein found in red blood cells. This indicates blood loss somewhere in the colon due to CRC or other conditions, like colitis, inflammatory bowel disease, or ulcers. Other test kits look for abnormal DNA, which could indicate cancer. A positive result from an at-home kit would lead to additional testing with a physician.

Studies suggest that a combination of annually mailed fecal immunochemical test (FIT) kits and patient navigation could significantly increase screening rates:

  • A 2018 meta-analysis of eight different strategies designed to increase participation found that mailed FIT plus patient navigation boosted screening rates by 20%.
  • A 2019 microsimulation of multiple interventions among Medicaid patients also found that this strategy yielded the greatest participation increase, in this case, 12%.

Patient navigators are trained members of a clinical team that help patients overcome barriers to care and understand the medical system. Their impact has been studied in multiple settings and treatment scenarios where their efforts have generally increased patient care rates and lowered costs. 

Growing numbers of clinicians are heeding these results, and at-home testing is on the rise (boosted also by the COVID-19 pandemic and the desire to keep healthy people out of clinical settings). Some insurers (Kaiser Permenante, the Veterans Administration) now proactively mail FIT kits each year to applicable enrollees.

The downside to at-home kits is that they are less accurate than a colonoscopy. There are many brands available, but in general they are less sensitive (meaning more false positives) and have lower specificity (meaning more false negatives). However, a 2019 meta-analysis of fecal immunochemical tests (FIT) found them to be nearly as effective as colonoscopies when used every year. Various labs are working on new iterations of these kits, and it’s certain they will continue to improve. 

Better Colonoscopy Prep

Individuals choosing to get a colonoscopy will find that process getting a bit easier. Currently, patients have to drink about a gallon of laxative solution the day before the procedure in order to clear the colon. But many patients dislike the taste of the prep solution and don’t finish it. This in turn reduces digestive “flushing” and limits clarity in the colon. Data have consistently shown an “adenoma miss rate” of 30-40% when the colon is inadequately prepped. Often a physician will have to reschedule a procedure, and this reduces screening rates and increases costs. 

Recent FDA approval of a tablet alternative to the liquid prep would allow patients to just drink water for their hydration. It may seem like a small tweak, but doctors know that any factor facilitating colonoscopy prep will increase participation rates.

Closing the Colonoscopy Loophole 

Another victory for CRC is the closing of the “colonoscopy loophole.” It’s typical (and beneficial) that gastroenterologists remove any polyps that are found during a screening colonoscopy. This is a much more common-sense approach than simply identifying the polyps, informing the patient, and then going back in for a separate procedure to remove them. Yet, some insurers and Medicare (again, as authorized by the Affordable Care Act) had categorized the colonoscopy itself as a preventative procedure (with full coverage), but any polyp removal as a diagnostic test. 

It was not unusual for patients to wake up from a colonoscopy and find that a “covered” procedure now came with a large bill to meet deductibles, co-pays, or premiums. Doctors knew these potential costs kept some people from screening. The “Removing Barriers to Colorectal Cancer Screening Act of 2020” was included in the COVID-19 relief bill and passed last December, removing this differentiation and providing full coverage for both scoping and polyp removal.

One-third of eligible US adults (currently about 22 million people) still aren’t screened for CRC, and our society has a lot of work to do in reaching our at-risk populations. Taken together, the advances outlined here are a step in the right direction, and will ultimately reduce both the incidence and deaths from colorectal cancer.

Edited by Rachel Cherney

Header photo. Source: Mercy Medical Center 

References

Davis, M., Nambiar, S., Mayorga, M., Sullivan, E., Hicklin, K., O’Leary, M., . . . Wheeler, S. (2019, October 18). Mailed FIT (Fecal immunochemical test), navigation or patient reminders? Using microsimulation to Inform selection of interventions to increase colorectal cancer screening in Medicaid enrollees. Retrieved March 01, 2021, from https://www.sciencedirect.com/science/article/pii/S0091743519303123?via%3Dihub

Davis, M., Renfro, S., Pham, R., Lich, K., Shannon, J., Coronado, G., & Wheeler, S. (2017, May 13). Geographic and POPULATION-LEVEL disparities in colorectal cancer testing: A Multilevel analysis of Medicaid and commercial claims data. Retrieved March 01, 2021, from https://www.sciencedirect.com/science/article/abs/pii/S0091743517301640

D’Souza, S. M. (2019). The dirty side of colonoscopy: Predictors of poor bowel preparation and novel approaches to overcome the shortcomings. British Journal of Gastroenterology, 1(1). doi:10.31488/bjg.1000103

Imperiale, T. F., Gruber, R. N., Stump, T. E., Emmett, T. W., & Monahan, P. O. (2019). Performance characteristics of fecal immunochemical tests for colorectal cancer and advanced adenomatous polyps. Annals of Internal Medicine, 170(5), 319. doi:10.7326/m18-2390

Michael K. Dougherty, M. (2018, December 01). Evaluation of interventions to Increase colorectal cancer Screening rates in the United States. Retrieved March 01, 2021, from https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2706176

Recommendation: Colorectal Cancer: Screening: the United States Preventive Services Taskforce. (2020, October 27). Retrieved March 01, 2021, from https://uspreventiveservicestaskforce.org/uspstf/draft-update-summary/colorectal-cancer-screening3

Siegel, R. L., Miller, K. D., Goding Sauer, A., Fedewa, S. A., Butterly, L. F., Anderson, J. C., . . . Jemal, A. (2020). Colorectal Cancer Statistics, 2020. CA: A Cancer Journal for Clinicians, 70(3), 145-164. doi:10.3322/caac.21601

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