New guidelines from the American Cancer Society say colorectal cancer screenings should start at age 45 — five years younger than federal recommendations.
Released May 30, the guidelines are based on a modeling analysis that took into account the rising rates of colorectal cancer in younger people and the benefit-to-burden balance of screening.
The new guidelines said people should get screened every one to 10 years, depending on what method is used. Visual structural exams — looking at the colon and rectum using scopes, cameras or special imaging tools such as colonoscopies — are called for every five to 10 years. Stool-based tests — which are less invasive and look for blood or abnormal genetic material in feces — are recommended every one to three years.
The guidelines differ from those of the U.S. Preventive Services Task Force, a panel of experts appointed by the U.S. Department of Health and Human Services that reviews evidence and develops research-based recommendations for clinical practice. In 2016, the task force reviewed existing science and conducted its own modeling analysis. It determined that earlier screenings did not prevent many early deaths from colorectal cancer. Instead, the task force recommended that screenings begin at age 50 and continue until age 75.
The new American Cancer Society guidelines disagree, however, recommending:
• Age 45: Starting screenings
• Ages 50 to 75: Continuing screenings for adults expected to live at least 10 more years
• Ages 76 to 85: Talking with a doctor to decide if screening is recommended
• Ages 85 and older: Forgoing screenings
Most colorectal cancer screening studies have focused on people ages 50 and older, and there is less direct evidence on harms and benefits for younger screenings. Therefore, the American Cancer Society’s lower starting age is a “qualified recommendation.”
But the tradeoff between lower “mortality and incidence and increased number of colonoscopies was favorable,” the American Cancer Society said. Differences between study results occurred because it considered new rates of colorectal cancer in younger adults into its modeling while others did not, the society said.
Incidence and mortality rates of colon cancer have been decreasing among older adults since around 2000, but have been increasing among adults under age 55. The American Cancer Society found that between 1994 and 2014, there was a 51 percent increase of colorectal cancer among adults under 55. Rates have been increasing faster for adults ages 40 to 49 compared with adults ages 50 to 54. In a May CA: A Cancer Journal for Clinicians study, researchers said the causes for the increase are unknown.
Rates of colorectal cancer vary by sex, race and ethnicity. After age 35, colorectal cancer rates for males are higher than females. Alaska Natives and some American Indians have the highest rates of colorectal cancer among all race and ethnicity groups. Historically, blacks have had a higher incidence of colorectal cancer compared with whites, but in the past decade, rates have increased for both groups.
“When we began this guideline update, we were initially focused on whether screening should begin early in racial subgroups with higher colorectal cancer incidence, which some organizations already recommend,” said Richard Wender, MD, chief cancer control officer of the American Cancer Society, in a news release. “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.”
The new recommendations were published in CA: A Cancer Journal for Clinicians.
To read the American Cancer Society guidelines, visit https://onlinelibrary.wiley.com/doi/full/10.3322/caac.21457
- Copyright The Nation’s Health, American Public Health Association
