Follow-Up Colonoscopy Rates Remain Low After Blood-Based Colorectal Cancer Screening, UCLA Study Finds
Fewer than half of patients followed up with a colonoscopy after abnormal blood-based colorectal cancer screening.
A new study from UCLA Health reveals that while blood-based tests for colorectal cancer offer a more convenient screening option, many patients do not complete the critical follow-up colonoscopy needed to confirm abnormal results.
The research, led by investigators at the UCLA Health Jonsson Comprehensive Cancer Center, found that only 49% of patients who received an abnormal blood-based screening result completed a colonoscopy within six months. Over the two-year study period, just 56% of patients ever completed the follow-up procedure.
“Blood-based colorectal cancer screening is promising, but it only works if individuals complete the follow-up colonoscopy,” said Folasade May, MD, PhD, MPhil, associate professor of medicine at the David Geffen School of Medicine at UCLA and senior author of the study. “More efforts are needed to help patients follow through to actually diagnose and treat the disease.”
Follow-Up Gaps Mirror Stool-Based Screening Rates
According to the study, the follow-up rates for blood-based tests were comparable to those observed for stool-based screenings but remain far below the levels considered optimal for timely detection and treatment of colorectal cancer. Colonoscopy is a crucial next step after an abnormal screening result, allowing physicians to confirm the presence of cancer or pre-cancerous polyps.
The study also highlighted disparities related to insurance type and overall health. Patients with Medicare Advantage were significantly less likely to complete a follow-up colonoscopy compared to those with private insurance. Additionally, individuals with fewer health conditions were more likely to pursue timely follow-up care. Race and ethnicity were not significant predictors of follow-up completion in this cohort, in contrast to prior research on stool-based screening.
Colorectal Cancer Screening Remains a Vital Public Health Priority
Colorectal cancer is the second leading cause of cancer-related deaths in the United States among men and women combined. Experts emphasize that early detection through regular screening can save lives. However, many patients avoid screening due to fear, limited access, or challenges with preparation for traditional tests such as colonoscopy or stool-based screening.
Folasade May, MD, PhD, MPhil, associate professor of medicine at the David Geffen School of Medicine at UCLA said, “This study underscores that convenience alone does not ensure early cancer detection. Patients, clinicians, and health systems must work together to ensure that abnormal results lead to timely diagnostic procedures.”
Study Design and Methodology
The researchers conducted a retrospective analysis of medical claims data from more than 6,000 individuals aged 45 and older who received the Shield blood-based colorectal cancer screening test between 2022 and 2024. The analysis focused on 452 patients who received an abnormal result and tracked whether they completed a follow-up colonoscopy within six months.
Timothy Zaki, MD, a senior gastroenterology fellow at UCLA Health and the study’s first author, said the findings provide valuable real-world insight into patient behavior after blood-based screenings. “Understanding how often patients follow through with colonoscopy after an abnormal result is critical to assessing the potential impact of these newer screening methods on colorectal cancer outcomes,” he said.
Implications for Clinical Practice
The study, published in the journal Gastroenterology, emphasizes that timely follow-up is essential to ensure that blood-based screening tests translate into meaningful health benefits. Delays or failures to undergo colonoscopy after an abnormal result can compromise early detection and treatment, reducing the overall effectiveness of screening programs.
May added, “Our findings highlight the need for targeted interventions to improve follow-up rates, particularly among patients with Medicare Advantage or multiple health conditions. These steps are crucial to fully realize the potential of blood-based colorectal cancer screening.”
—Janette Wider
s
