Prevalence, Reasons for Unsatisfactory FIT Samples for Colorectal Cancer Screening

A retrospective cohort study examined the prevalence and reasons for an unsatisfactory fecal immunochemical test (FIT)—a common colorectal cancer screening modality.

Results of the study were published in Cancer Epidemiology, Biomarkers & Prevention.

While colorectal cancer screening is able to detect disease at an early stage, only around 72% of eligible adults were up to date on colorectal cancer screening in 2021. FIT is considered an effective colorectal cancer screening modality, but little is known about the prevalence, reasons, and testing after an unsatisfactory FIT or a FIT that cannot be processed due to inadequate stool specimen or incomplete labeling.

Po-Hong Liu, MD, MPH, of UT Southwestern Medical Center, and colleagues assessed unsatisfactory FIT among average-risk patients aged 50 to 74 years who completed an index FIT from 2010 to 2019 within the Dallas-based Parkland Health system, which primarily provides care for uninsured, lower-income, and racial or ethnic minority individuals. Among the 56,980 patients who completed an index FIT, 10.2% had an unsatisfactory FIT.

Researchers determined prevalence of unsatisfactory FIT and categorized reasons hierarchically. Multivariable logistic regression models were utilized to identify factors associated with unsatisfactory FIT, as well as subsequent testing within 15 months of the unsatisfactory FIT.

Among the identified reasons for unsatisfactory FIT were inadequate specimen (51%), incomplete labeling (27%), old specimen (13%), and broken/leaking container (8%). Additionally, researchers found that unsatisfactory FIT was associated with being male (odds ratio [OR], 1.10; CI, 1.03-1.16), Black (OR, 1.46; CI, 1.33-1.61), Spanish speaking (OR, 1.12; CI, 1.01-1.24), and on Medicaid (OR, 1.42; CI, 1.28-1.58) and having received the FIT by mail (OR, 2.66; CI, 2.35-3.01).

Only 41% of those with an unsatisfactory FIT completed a subsequent test within 15 months (median, 4.4 months), they added, and patients aged 50 to 54 years (OR, 1.16; CI, 1.01-1.39) and those having received the FIT by mail (OR, 1.92; CI, 1.49-2.09) were more likely to complete a subsequent test.

Overall, Black patients were 1.46 times more likely to submit an unsatisfactory FIT, and patients who primarily spoke Spanish were 1.2 times more likely to submit an unsatisfactory FIT, Dr. Liu and colleagues reported.

“Screening programs should address these breakdowns, such as specimen collection and labeling, to improve real-world effectiveness,” they concluded.