Colorectal cancer in older adults after the USPSTF's 2008 updated screening recommendation

Background: Colorectal cancer (CRC) screenings can improve detection and prevent precancerous polyps from becoming malignant tumors. In 2008, the United States Preventive Services Task Force (USPSTF) updated their policy and no longer recommended that adults over age 75 screen for CRC. We evaluated how this policy update impacted screening behaviors and CRC outcomes in older adults. Methods: We obtained data from the Behavioral Risk Factor Surveillance System to analyze blood stool and colonoscopy screening, the Surveillance, Epidemiological, End Results program to analyze CRC staging and survival, the National Association of Centralized Cancer Registries to analyze CRC incidence, and the National Center for Health Statistics to analyze mortality. With a difference-in-differences design, we compared the changes in outcome trends of the exposed group (age 75+), before and after 2008, with the changes in trends of a similar unexposed group (age 65-74). Results: There was no association between the 2008 update and blood stool tests in older adults. We did, however, find that the update was associated with a 3.0 %-point decline in the probability of older adults completing a colonoscopy within the past two years (C.I. = -4.0, -2.0). Among older adults diagnosed with CRC, the update was associated with a 1.5 %-point increase in the probability of presenting at an advanced stage (C.I. = 1.1, 1.9). Finally, the update was also associated with lower CRC incidence (Est. = -13.9 cases/100,000 population; C.I. = -22.6, -5.1) and mortality rates (Est. = -5.6 deaths/100,000 population; C.I. = -10.1, -1.1). We observed the largest associations between the policy and CRC outcomes in adults age 85+. Discussion: The USPSTF's 2008 recommendation was associated with reduced colonoscopies, especially in adults over age 85. Whether this recommendation, or the 2021 updated guidance, optimizes population health by reducing the burden of CRC screening in older adults remains unknown.