Colorectal Cancer Researchers Ask Test Subjects to Get Their Hands Dirty

A new study leaves colorectal cancer researchers empty-handed.


Medical researchers who offered gift cards in exchange for an at-home colorectal cancer screening have learned no amount of money can convince people to get their hands dirty, a new study reveals.

A trip to the gastroenterologist can seem dreadful, even if colorectal cancer is the second-leading cause of cancer-related deaths in America. A much less-invasive screening method that involves pooping in a tube at home might be the solution, but it hasn’t proven to be a popular idea.

Scientists at the University of Pennsylvania describe in a paper, published Friday in JAMA Network Open, how they offered 900 people one of the following options for filling a “sample collection tube” with poop: a $10 gift card (which they received whether or not they sent in a sample), a $10 gift card once they sent in their sample, or an entry into a lottery with a one-in-ten chance of winning a $100 gift card once they sent in the sample. (They also offered some people no financial incentive — after all, shouldn’t health be its own reward?)

But they found that none of the people who were offered financial incentives were significantly more likely to send in their fecal sample kits than the people who weren’t offered incentives.

A fecal immunochemical test (FIT) kit allows someone to take a sample of their own feces at home to send it to a lab for further analysis.
A fecal immunochemical test (FIT) kit allows someone to take a sample of their own feces at home to send it to a lab for further analysis.

Though it was clear that the people who received financial incentives weren’t any more likely to send in a sample, there was a silver lining to the findings.

Only two-thirds of older adults are up to date on their screenings. All of the people involved in the experiment were past-due for screenings, meaning they hadn’t gotten a colonoscopy within the last ten years, a flexible sigmoidoscopy in the last five years, or a stool test in the past year. And over the six-month duration of the study, 28.9 percent of the participants returned their tests. In other words, sending a reminder in the mail pushed some people to get checked out, but the financial incentive didn’t make much more of a difference in increasing screening rates.

The doctors were particularly pleased about this results because the notifications the patients received did not come from a face-to-face conversation with a doctor.

“This was a substantial rate of [colorectal cancer] screening uptake in a population that was not up-to-date and typically received recommendation for colonoscopy in the clinic setting,” they write.

Failing to stay up-to-date on colorectal cancer screening can double a person’s risk of dying from the disease. Even though a mailed-in fecal immunochemical test kit isn’t the gold standard of preventive care, it can still detect blood in a person’s feces, which can be a warning sign of colorectal cancer.

In an invited commentary, Liam Rose, Ph.D., a health economist at Stanford University, writes that even though the financial incentives didn’t work, this study shows that simply sending people a reminder in the mail could be part of an effective strategy to encourage them to get screened.

“There have now been a number of randomized clinical trials on initiatives that attempt to increase compliance of [colorectal cancer] screening, with positive but somewhat varied results,” he writes. “It is clear, however, that outreach in the form of sending kits by mail has a positive effect and that pecuniary incentives seem to have little to no effect on increasing completion rates beyond simply sending the patient a test kit and a reminder.”

This study was limited to people within a fairly close radius of the University of Pennsylvania, so most readers probably wouldn’t be eligible for one of these screenings. But any adults who are concerned about their colorectal cancer status should check out this page from the CDC on what you should know about colorectal cancer screening.


IMPORTANCE: Mailing fecal immunochemical test (FIT) kits to patients’ homes has been shown to boost colorectal cancer screening rates, but response rates remain limited, and organized programs typically require repeated outreach attempts. Behavioral economics has shown that offering salient financial incentives to patients may increase participation in preventive health.

OBJECTIVE: To compare the impact of different financial incentives for mailed FIT outreach.

DESIGN, SETTING, AND PARTICIPANTS: This 4-parallel-arm randomized clinical trial included patients aged 50 to 75 years who had an established primary care clinician, at least 2 visits in the prior 2 years, and were eligible for colorectal cancer screening and not up-to-date. This study was conducted at urban primary care practices at an academic health system from December 2015 to February 2018. Data analysis was conducted from March 2018 to September 2018.

INTERVENTIONS: Eligible patients received a letter from their primary care clinician that included a mailed FIT kit and instructions for use. They were randomized in a 1:1:1:1 ratio to receive (1) no financial incentive; (2) an unconditional $10 incentive included with the mailing; (3) a $10 incentive conditional on FIT completion; or (4) a conditional lottery with a 1-in-10 chance of winning $100 after FIT completion.

MAIN OUTCOMES AND MEASURES: Fecal immunochemical test completion within 2 and 6 months of initial outreach.

RESULTS: A total of 897 participants were randomized, with a median age of 57 years (interquartile range, 52-62 years); 56% were women, and 69% were black. The overall completion rate across all arms was 23.5% at 2 months. The completion rate at 2 months was 26.0% (95% CI, 20.4%-32.3%) in the no incentive arm, 27.2% (95% CI, 21.5%-33.6%) in the unconditional incentive arm, 23.2% (95% CI, 17.9%-29.3%) in the conditional incentive arm, and 17.7% (95% CI, 13.0%-23.3%) in the lottery incentive arm. None of the arms with an incentive were statistically superior to the arm without incentive. The overall FIT completion rate across all arms was 28.9% at 6 months, and there was also no difference by arm. The completion rate at 6 months was 32.7% (95% CI, 26.6%-39.3%) in the no incentive arm, 31.7% (95% CI, 25.7%-38.2%) in the unconditional incentive arm, 26.8% (95% CI, 21.1%-33.1%) in the conditional incentive arm, and 24.3% (95% CI, 18.9%-30.5%) in the lottery incentive arm.

CONCLUSIONS AND RELEVANCE: Mailed FIT resulted in high colorectal cancer screening response rates in this population, but different forms of financial incentives of the same expected value ($10) did not incrementally increase FIT completion rates. The incentive value may have been too small or financial incentives may not be effective in this context.