American Cancer Society Updates Colorectal Cancer Screening Guideline
An updated American Cancer Society guideline now says colorectal cancer screening should begin at age 45 for people at average risk, based in part on data showing rates of colorectal cancer are increasing in young and middle-aged populations. The updated recommendations were published by Wolf et al in CA: A Cancer Journal for Clinicians.
The new recommended starting age is based on colorectal cancer incidence rates, results from microsimulation modeling that demonstrate a favorable benefit-to-burden balance of screening beginning at age 45, and the expectation that screening will perform similarly in adults aged 45 to 49 as it does in adults for whom screening is currently recommended (50 and older).
Current Recommendations
The American Cancer Society recommends:
- Adults aged 45 and older with an average risk of colorectal cancer should undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) exam, depending on patient preference and test availability.
- The change in starting age is designated as a “qualified recommendation,” because there is less direct evidence of the balance of benefits and harms, or patients’ values and preferences, related to colorectal cancer screening in adults aged 45 to 49 since most studies have only included adults aged 50 and older. The recommendation for regular screening in adults aged 50 years and older is designated as a “strong recommendation,” on the basis of the greater strength of the evidence and the judgment of the overall benefit.
- As part of the screening process, all positive results on noncolonoscopy screening tests should be followed up with timely colonoscopy.
- Average-risk adults in good health with a life expectancy of greater than 10 years should continue colorectal cancer screening through age 75. Clinicians should individualize colorectal cancer screening decisions for individuals aged 76 through 85, based on patient preferences, life expectancy, health status, and prior screening history. Clinicians should discourage individuals over age 85 from continuing colorectal cancer screening.
The recommended options for colorectal cancer screening are: fecal immunochemical test annually; high-sensitivity guaiac-based fecal occult blood test annually; multitarget stool DNA test every 3 years; colonoscopy every 10 years; computed tomography colonography every 5 years; and flexible sigmoidoscopy every 5 years.
The new guideline does not prioritize among screening test options. Given the evidence that adults vary in their test preferences, the guidelines development committee emphasized that screening rates could be improved by endorsing the full range of tests without preference. The American Cancer Society has developed new materials to facilitate conversations between clinicians and patients to help patients decide which test is best for them.
“When we began this guideline update, we were initially focused on whether screening should begin earlier in racial subgroups with higher colorectal cancer incidence, which some organizations already recommend,” said Richard C. Wender, MD, Chief Cancer Control Officer for the American Cancer Society. “But as we saw data pointing to a persistent trend of increasing colorectal cancer incidence in younger adults—including American Cancer Society research that indicated this effect would carry forward with increasing age—we decided to reevaluate the age to initiate screening in all U.S. adults.”
Incidence of Colorectal Cancer
Colorectal cancer incidence has declined steadily over the past 2 decades in people 55 and over due to screening that results in removal of polyps, as well as changes in exposure to risk factors, but there has been a 51% increase in colorectal cancer among those under age 50 since 1994. Death rates in this age group have also begun to rise in recent years, indicating that increased incidence rates do not appear to be solely the result of increased use of colonoscopy. A recent analysis found that adults born around 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared with adults born around 1950, who have the lowest risk.
While the colorectal cancer incidence rate among adults aged 45 to 49 is lower than it is among adults aged 50 to 54 (31.4 vs 58.4 per 100,000), the higher rate in the 50- to 54-year-old age group is partially influenced by the uptake of screening at age 50, which leads to an increase in the incidence rate due to detection of prevalent cancers before symptoms arise. Since adults in their 40s are far less likely to be screened than those in their 50s (17.8% vs 45.3%), the true underlying risk in adults aged 45 to 49 years is likely closer to the risk in adults aged 50 to 54 than the most recent age-specific rates would suggest. Importantly, studies suggest the younger-age cohorts will continue to carry the elevated risk forward with them as they age.
Organizations have increasingly relied on modeling to evaluate alternative colorectal cancer screening strategies, including variations in the age to start and stop screening. Two of three microsimulation models conducted for the 2016 U.S. Preventive Services Task Force (USPSTF) screening recommendations suggested that starting colonoscopy screening with an interval of 15 years at age 45 vs age 50 provided a slightly more favorable balance between the benefits and burden of screening. However, the USPSTF elected not to recommend the younger starting age in 2016, judging the estimated additional benefit to be “modest” and also noting that one of the three models did not corroborate the additional benefit and there was a lack of empirical evidence to support the change.
A new modeling study commissioned by the ACS for this review extended these analyses by incorporating more recent studies of the rising incidence trends in younger adults and showed that multiple screening strategies beginning at age 45, including colonoscopy at the conventional 10-year interval, had a more favorable benefit-to-burden ratio with more life-years gained compared with starting screening at age 50.
“One of the most significant and disturbing developments in [colorectal cancer] is the marked increase in [colorectal cancer] incidence—particularly rectal cancer—among younger individuals,” concluded the authors. “While the causes of this increase are not understood, it has been observed in all adult age groups below the age when screening has historically been offered, and is contributing significantly to the burden of suffering imposed by premature [colorectal cancer] mortality. Incorporating this epidemiological shift into contemporary modeling of [colorectal cancer] screening demonstrated that the benefit-burden balance is improved by lowering the age to initiate [colorectal cancer] screening to 45 years. Lowering the starting age is expected to benefit not only the segments of the population who suffer disproportionately from [colorectal cancer]—blacks, Alaska Natives, and American Indians—but also those individuals otherwise considered to be at average risk. Moreover, epidemiological trends in cohorts as young as those born in 1990 suggest that the higher risk of developing [colorectal cancer] will be a persistent concern for decades to come,” they wrote.
Commentary on the Guideline Change
"I have seen first-hand the dangers of early-onset colon cancer. My late husband, Jay Monahan, was just 41 when he was diagnosed more than 20 years ago. Doctors have noticed an alarming trend—an increase in people like Jay, under age 50, being diagnosed with the disease. I'm thrilled that the American Cancer Society has responded and revised its guidelines, lowering the recommended age to start screening to 45. While little is known about the underlying reasons for the rise, the ACS, Stand Up To Cancer, and others in the advocacy community are working to get these critical answers. In the meantime, one thing is clear: Screening can often prevent this cancer. I urge everyone 45 and over to get screened,” said Stand Up To Cancer Co-Founder Katie Couric.
Michael Sapienza, Chief Executive Officer of the Colorectal Cancer Alliance, said, “The increasing incidence of colorectal cancer in younger adults is an epidemic within the cancer community. By 2030, 10.9% of all colon cancers and 22.9% of all rectal cancers will be diagnosed in patients younger than age 50. Together we must defy and redefine the odds. We fully endorse the American Cancer Society's new proposed guideline that colorectal cancer screening should begin at age 45 for people at average risk.… If this new guideline is adopted, lives will be saved."
He continued, "The Colorectal Cancer Alliance established the Never Too Young Advisory Board so we may all join forces and take action around the issue of young-onset colorectal cancer. We plan to invest $10 million in critical research by 2021, which will include learning why we are seeing an increase in young-onset colorectal cancer, doubling the number of constituents we serve, and saving 100,000 lives by 2026 through increased screening."
Finally, Mr. Sapienza noted, "Across America, our Never Too Young Advisory Board will work tirelessly to educate primary care physicians and gastrointestinal medical professionals around symptoms of young-onset colorectal cancer. We will challenge insurance companies to step up to the plate and protect the young-onset population. Today's action by the American Cancer Society does not mean colorectal cancer screening tests will now be covered by insurance plans. We commend the American Cancer Society and fully endorse their commitment to saving lives.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
