When Maria Santos completed her first at-home colon cancer screening test, she felt relieved. The stool test came back negative. But then the busy months piled up, and she never repeated it — a pattern that thousands of patients across the country fall into every year, often without realizing the consequences.
A major new study from Rutgers Health shows that patients who consistently repeat their annual at-home colon cancer test catch the disease early far more often than those who skip retesting. Among patients diagnosed with colorectal cancer in the study, 56% of people who retested every year were diagnosed at the earliest, most treatable stage. For those who never retested after their first negative result, that number dropped to 44%.
The research followed 492,812 adults from four large health systems for up to ten years after an initial negative at-home test. The at-home test, called a FIT test, involves poking a stool sample with a plastic stick and mailing it to a lab, which checks for tiny amounts of blood that can signal cancer or growths that could become cancer.
"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."
That message turned out to be the study's most striking finding. Even after accounting for differences in patient age, health, and other factors, the odds of a patient consistently retesting varied by more than 20 times depending on which health system provided their care. The gap came down to how each system reached out to patients.
Kaiser Permanente Northern California had the highest retesting rates. The system mailed FIT kits directly to patients who were overdue and made kits available at primary care offices, pharmacies, labs, and flu clinics — catching people who don't visit doctors regularly. Other systems did less outreach, and their retesting rates suffered.
Overall, 54% of patients in the study repeated their annual test in more than three out of every four subsequent years. About 30% did it at least once but not consistently, and 16% never retested at all.
"For those doing FIT testing, this is not a one-and-done testing strategy," Halm said. "You need to check your rear every year."
The study also found that patients who had seen a primary care doctor in the previous year were more likely to stay on track with screening, as were people who had done at-home testing before and those who were older and healthier.
Researchers acknowledged some limits to the findings. The study started with people who had already completed one negative test, so it doesn't cover people who have never been screened at all. The study period also largely came before newer combined stool DNA tests became common.
Still, Halm said the implications are clear: simply making an at-home test available is not enough. Health systems that actively reach out to patients — by sending reminders, mailing kits, and making testing easy to access — can dramatically improve how many people catch colon cancer early, when it is most curable.