SAN DIEGO—Offering flexible options for colorectal cancer screening doubled screening rates, cut cancer incidence by a third, halved deaths, and reduced racial differences in outcomes to nearly zero, according to results from a long-term study at a major integrated health system presented at DDW 2025.
To better understand variations among ethnic groups in the development of CRC and CRC-related mortality and to assess how screening outreach could shift diagnoses and death rates, Douglas Corley, MD, PhD, the chief researcher officer at the Kaiser Permanente’s Division of Research, in Northern California, and his co-investigators from Kaiser and the Ohio State University Wexner Medical Center embarked on a nearly 20-year study that included 1.1 million adults aged 50 to 75 years (abstract 271). The participants were in California but reflected national demographic proportions.
During the initial phase of the study, between 2000 and 2006, the researchers did not perform any outreach to patients to create a control figure.
From 2006 to 2007, the researchers began to use a simple outreach technique not unlike a standard visit to the dentist: They regularly sent study participants postcards in the mail to inquire if they had had a colonoscopy or other colorectal screening recently, and if not, to contact the team to schedule an in-person exam. If participants indicated that they were not up to date on screening, fecal immunochemical tests were sent automatically so participants could perform testing at home.
By the close of the study in 2019, the rate of people up to date on their CRC screenings rose to 79.8%-more than double the 2000 rate of 37.4%.
Between 2007 and 2010, CRC incidence initially rose “due to detection,” Dr. Corley said. But from 2010 to 2019, incidence rates fell among white, Black, Asian and Hispanic groups. Incidence rates increased from 109.1 to 126.4 cases per 100,000 in 2002, peaked during 2008-2010, which the investigators noted is “consistent with increased early detection of cancers.” The incidence rates then “declined, consistent with cancer prevention from polyp detection and removal” to 66.3, 78.3, 78.4, and 87.1 per 100,000 in Asian, Hispanic, white and Black participants in 2019.
In addition, death rates also fell dramatically between 2002 and 2019, with a 50% drop across all groups, Dr. Corley noted. CRC-related deaths declined from 27.1 to 15.3 deaths per 100,000 in Asian, 39.8 to 20.7 in white, 42.1 to 21.9 in Hispanic, and 52.2 to 23.5 in Black participants.
Although CRC incidence rates in 2019 still indicated that Black people were more likely to be diagnosed with and die of CRC, Dr. Corley said the proportional difference between Black participants and other ethnic groups was “no difference beyond random chance."
During a media briefing before the meeting, Dr. Corley said the element of choice was invaluable because many patients don’t want to undergo colonoscopy, which requires taking a day off work, potentially finding transportation to the appointment, bowel preparation and the general discomfort of the process. But, he added, participants engaged with these postcard reminders consistently over time because there was a choice of how to screen, including an option that didn’t require leaving home.
The results from this assessment show that screening outreach can lower disease incidence and mortality, Dr. Corley said. “Systematic, comparable outreach can provide a level playing field for completion of preventive care. The main thing has been choice and reaching people at their homes. … Outreach without an in-person visit can make an extraordinary difference.”
—Karen Fischer