Stool-based colorectal cancer testing produces a high proportion of unsatisfactory samples
Click Here to Manage Email Alerts
Key takeaways:
- Males, African Americans and people with Medicaid are more likely to submit an unsatisfactory sample.
- Less than half of participants submitted a subsequent test following an unsatisfactory sample.
Over 10% of fecal immunochemical tests used for routine colorectal cancer screening contained unsatisfactory samples that could not be processed, according to study findings published in Cancer Epidemiology, Biomarkers and Prevention.
Nair and colleagues identified patient-related reasons for the majority of unsatisfactory samples, with less than half of such patients completing a subsequent test following an unsatisfactory sample.
“Results from our study were surprising because the U.S. Multi-Society Task Force recommends that the proportion of unsatisfactory fecal immunochemical tests be less than 5%,” Rasmi G. Nair, MBBS, PhD, assistant professor at Peter O’Donnell Jr. School of Public Health of UT Southwestern Medical Center, told Healio.
“However, our study using a decade worth of real-world data for 56,980 patients from an integrated safety-net health system demonstrates that the prevalence of unsatisfactory fecal immunochemical tests is about10% — more than double the recommended threshold — mostly due to errors in patients completing the test,” she added. “Beyond the fact that one in 10 tests are not usable, we also showed that the majority of these patients do not undergo another screening test within 15 months, thereby resulting in a gap of being screen-up-to-date.”
Background and methodology
Fecal immunochemical tests (FITs) are an effective colorectal cancer screening modality, yet little is known about prevalence and factors contributing to unsatisfactory FITs that cannot be processed at a laboratory.
Nair and colleagues conducted a retrospective cohort study examining unsatisfactory FIT among average-risk individuals (n = 56,980) aged 50-74 years within the Dallas-based Parkland Health system from 2010 to 2019.
They determined prevalence of unsatisfactory FIT and categorized reasons hierarchically, as well as multivariable logistic regression models to identify factors associated with unsatisfactory FIT and subsequent testing within 15 months of a failed sample.
Results
Among the study participants who completed an index FIT, 10.2% had an unsatisfactory test, with reasons for such failures including inadequate specimen (51%), incomplete labeling (27%), old specimen (13%) and broken/leaking container (8%).
Unsatisfactory FIT appeared associated with being male (OR = 1.1; 95% CI, 1.03-1.16), being Black (OR = 1.46; 95% CI, 1.33-1.61), being a Spanish speaker (OR = 1.12; 95% CI, 1.01-1.24), being on Medicaid (OR = 1.42; 95% CI, 1.28-1.58) and receiving FIT by mail (OR = 2.66; 95% CI, 2.35-3.01).
Of those with an unsatisfactory FIT, 41% completed a subsequent test within 15 months (median, 4.4 months).
Adults aged 50-54 years (OR = 1.16; 95% CI, 1.01-1.39) and those who received FIT by mail (OR = 1.92; 95% CI, 1.49-2.09) more likely completed a subsequent test.
Researchers noted several study limitations, including being performed in a safety-net health system so the data gathered may not be generalizable to other practices or populations.
Next steps
Researchers noted that screening programs should work to address the breakdowns observed through this study — such as through specimen collection and labeling — to improve real-world effectiveness.
“Although our laboratory system recorded reasons for unsatisfactory FIT, lack of details led to an incomplete picture about why a test was unsatisfactory,” Nair told Healio. “For instance, if the unsatisfactory FIT was due to an incomplete label, we could not delineate if the name, date or both were missing or unreadable, or if the patient truly understood the need to add this information to the testing tube, thereby making it difficult to ascertain if incomplete label was a system error or patient misunderstanding. Future research should aim to distinguish if the unsatisfactory FIT was due to a patient, provider or system error, and try to implement strategies to improve effectiveness of [colorectal cancer] screening programs based on reasons for unsatisfactory FIT at the appropriate level (patient, provider or system).
Nair also lamented the lack of follow-up for the majority of unsatisfactory FITs.
“This not only highlights the need for health care systems to implement a comprehensive approach to flagging and following up unsatisfactory FIT, but also indicates the need for design of comprehensive patient education to improve screening delivery in real-world settings,” she said.
For more information:
Rasmi G. Nair, MBBS, PhD, can be reached at Peter O’Donnell Jr. School of Public Health, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9066; email: rasmi.nair@utsouthwestern.edu.
References:
- Liu P, et al. Cancer Epidemiol Biomarkers Prev. 2023;doi:10.1158/1055-9965.EPI-23-0507.
- More than 10% of samples from a stool-based colorectal cancer test may be unsatisfactory (press release). Available at: https://www.aacr.org/about-the-aacr/newsroom/news-releases/more-than-10-of-samples-from-a-stool-based-colorectal-cancer-test-may-be-unsatisfactory/. Published on Nov. 15, 2023. Accessed Nov. 15, 2023.
Collapse
Click Here to Manage Email Alerts