Updated colorectal cancer screening effective for adults 45–50, study suggests

The updated national colorectal cancer screening guidelines that recommend screening begin at age 45—rather than 50—can benefit younger adults, a new Kaiser Permanente study found.

The study, published October 22 in Annals of Internal Medicine, included more than 267,000 Kaiser Permanente members in Northern California, Washington, and Colorado aged 45 to 50 who received their first invitation for colorectal cancer screening along with a fecal immunochemical test (FIT) kit between January and September 2022.

“The U.S. Preventive Services Task Force lowered the age to start screening in response to studies showing an increased rate of colorectal cancer in adults ages 45 to 49,” said co-first author Theodore R. Levin, MD, a research scientist at the Kaiser Permanente Division of Research (DOR) and a gastroenterologist with The Permanente Medical Group (TPMG).

“However, the change was based entirely on simulation modeling. We decided to collect real-world data on what happened when we began sending FIT kits to Kaiser Permanente members ages 45 to 49.”

Overall, close to 39% of adults ages 45 to 49 returned their FIT kit, compared with nearly 38% of adults aged 50. In the 45 to 49 age group, 3.6% of the adults had a positive result compared with 4% of the adults in the age 50 group.

In both groups, about two-thirds of the adults who had a positive FIT test went on to have a colonoscopy within 90 days of receiving the test result. Polyp detection during the colonoscopy was slightly lower in the younger group at 58.8% compared with 67.7% in the age 50 group.

However, colorectal cancer detection rates were similar: 2.8% of those ages 45 to 49 and 2.7% of those aged 50 received a cancer diagnosis following their colonoscopy.

Since 2008, Kaiser Permanente’s colorectal cancer screening program has provided FIT kits to all eligible members annually, starting at age 50. In January 2022, Kaiser Permanente adopted the Task Force’s new screening recommendations and expanded its program to include members ages 45 to 49.

“Our study suggests that adults ages 45 to 49 have a colorectal cancer risk that is similar to what we see in adults aged 50,” said senior author Jeffrey K. Lee, MD, MPH, a DOR research scientist and TPMG gastroenterologist.

“These results provide strong support for guidelines that recommend colorectal cancer screening begin at age 45. The low number of cancers we found also provides support for initially offering younger adults a non-invasive test, like FIT, to determine which patients would benefit from a colonoscopy.”