On June 10, 2025, Radiology published Perry Pickhardt MD’s study, “CT Colonography versus Multitarget Stool DNA Test for Colorectal Cancer Screening: A Cost-Effectiveness Analysis.” The study quickly made the news as several media outlets covered the research, including RSNA News, AuntMinnie.com, Applied Radiology, Physician’s Weekly and Yahoo.com.
The study revealed CT colonography as a more clinically effective and cost-saving method for colorectal screening compared to multitarget stool DNA (mt-sDNA) testing. While conventional colonoscopy is the standard for detecting signs of colorectal cancer, CT colonography and mt-sDNA are less invasive alternatives.
Dr. Pickhardt, along with coauthors Loredana Correale, PhD and Cesare Hassan, MD, PhD, chose to compare mt-sDNA and CT colonography because a recent Medicare expansion covers them. The expansion coincides with rising rates of colorectal cancer in younger patients, which in 2021 prompted the U.S. Preventive Services Task Force and several medical societies to lower the recommended age for colorectal cancer screening from 50 to 45. With the rising demand for testing and the availability of alternative methods, the study aimed to evaluate the effectiveness of these tests both clinically and in terms of cost.
The researchers used a Markov model to simulate the progression and screening outcomes of colorectal disease in a model of 10,000 individuals starting at age 45 and ending at 75. The model projected that 7.5% of participants would develop colorectal cancer without screening, which aligns with current findings.
The team examined three approaches for detecting colorectal cancer. One method implemented mt-sDNA testing every three years. The second used CT colonography every five year with optical coloscopy for immediate removal of polyps measuring at least 6 mm. The final method used a CTC strategy that involved three-year CT colonography follow-up for small polyps between 6 and 9 mm in addition to the removal of large polyps measuring over 10 mm through conventional colonoscopy.
The research found that both CT colonography and mt-sDNA screenings greatly reduced colorectal cancer incidence. However, both CT colonography strategies resulted in a 70-75% reduction in colorectal cancer incidence, while mt-sDNA achieved a 59% reduction.
Routine preventive evaluation is the best route to prevent and identify colorectal cancer in its early stages, but the current standard has its drawbacks.
“In the U.S., conventional colonoscopy remains the dominant screening test for colorectal cancer, despite the fact that it is the most expensive and invasive option,” said Dr. Pickhardt.
Optical colonoscopies require patients to prepare several days in advance of the procedure, limiting their diet and fluid intake. Patients are also required to bring another person to drive them home after the procedure, as the anesthesia takes up to 24 hours to wear off, impairing the ability to operate a vehicle safely.
The findings from Dr. Pickhardt and his team are reassuring as these affordable, noninvasive procedures will be in higher demand to combat colorectal cancer in younger patients. Medical providers can utilize the study’s findings to develop early cancer detection strategies that can better fit patients’ time and budgets compared to relying solely on conventional colonoscopies.
There are additional benefits as CT colonography can also assess other health conditions opportunistically.
“CT colonography can provide for extracolonic screening for things like osteoporosis and cardiovascular disease,” said Dr. Pickhardt.