Nearly half of patients who completed an at-home test for colorectal cancer fail to repeat the screening consistently, according to Rutgers Health researchers who also found primary care provider behaviors can increase patient consistency – and catch more cancers early.
“This isn’t just about a doctor’s recommendation or the individual prevention beliefs of a patient,” said Ethan Halm, vice chancellor for population health at Rutgers Health and lead author of the study. “Systems can have a powerful impact.” Halm, a professor at Rutgers Robert Wood Johnson Medical School, is also a member of the Cancer Prevention and Control Program at Rutgers Cancer Institute, the state’s only National Cancer Institute–designated Comprehensive Cancer Center together with RWJBarnabas Health.
The study in Clinical Gastroenterology and Hepatology followed 492,812 adults from four large health systems for up to a decade after a negative home stool fecal immunochemical test (FIT). Fifty-four percent repeated what is supposed to be an annual test in more than 75% of subsequent years, about 30% repeated it at least once and 16% never did it again.
Among patients who were subsequently diagnosed with colorectal cancer, advanced disease accounted for 19% of initial diagnoses in people who never retested themselves and 12% in the other two groups. Local-stage cancer, the easiest to treat, was the initial diagnosis of 56% of consistent retesters and 44% of never retesters.
Older and healthier patients were more likely to repeat screening, as were people with previous stool-testing experience and those who had seen a primary care clinician in the previous year.
That said, the biggest predictor – by far – of retesting rates was which of the four health systems provided their care. Even after researchers adjusted for patient differences, the odds of consistent testing varied more than 20-fold among the four systems studied: Parkland Health in Dallas and the Kaiser Permanente systems in Northern California, Southern California and Washington state.
The health-system differences pointed toward a practical way to improve results. Kaiser Permanente Northern California, which had the highest adherence, had long used organized population outreach strategies. The system mailed FIT kits to patients who were overdue and made kits available for anyone to pick up at primary care offices, laboratories, pharmacies and flu clinics. This helped catch patients who don’t regularly visit doctors for annual checkups or other treatments.
Halm said the sharp differences in patient retesting rates should inform how medical practices everywhere speak to patients on this issue and how health systems organize population health outreach programs. Proper colorectal cancer screening provides huge returns in both extra healthy years and medical spending avoided, Halm said.
The FIT test analyzed in the study has patients poke a stool sample with a plastic stick and return it to a lab, which checks for microscopic blood that can signal colorectal cancer or advanced polyps (little bumps that can turn into cancer). A positive result generally leads to a colonoscopy.
The FIT test is inexpensive and easy to conduct, but it is nowhere near as sensitive as a colonoscopy, so guidelines recommend that patients repeat it every year rather than every decade.
“For those doing FIT testing, this is not a one-and-done testing strategy,” said Halm, who is also the deputy chief population health officer at RWJBarnabas Health and a core member of the Rutgers Institute for Health, Health Care Policy and Aging Research. “You need to check your rear every year.”
The study noted some important limitations. It began with people who already had completed one negative stool test, so it doesn’t measure those who had never been screened or overall adherence across all methods. The study period also largely preceded widespread use of newer, combined stool DNA/FIT tests such as Cologuard.
For Halm, the main lesson is that making a home test available is only the first step. Health systems can improve the odds that screening continues by tracking who is overdue, proactively contacting patients and repeatedly putting tests in their hands.
“The best test is the test that gets done,” Halm said.
