A nationwide randomized controlled trial conducted in Scotland found that adding a suggested return deadline to mailed invitations for fecal immunochemical test (FIT) colorectal cancer (CRC) screening resulted in a small but significant increase in return rates. The study, published in The Lancet, evaluated the effectiveness of deadlines and planning tools in improving CRC screening participation.
The TEMPO clinical trial was embedded within the Scottish Bowel Screening Programme and included 40 000 adults aged 50 to 74 years eligible for routine CRC screening. Participants were randomly assigned to 1 of 8 groups that received either a standard invitation, a suggested FIT return deadline of 1, 2, or 4 weeks, a planning tool designed to help participants address potential barriers to completing the test, or a combination of both interventions. The primary outcome measured was the proportion of FITs returned correctly completed within 3 months. Statistical analyses were conducted to assess the significance of the interventions on FIT return rates.
Key findings:
- The control group, which received a standard invitation without any additional intervention, had a 3-month FIT return rate of 66.0%.
- A 2-week deadline without the planning tool produced the highest return rate at 68.0%, representing a 2.0% absolute increase compared with the control group.
- The planning tool, when provided without a deadline, was associated with a lower return rate (63.2%), and overall, it did not significantly improve FIT returns.
- Secondary analyses revealed that deadlines promoted earlier returns and significantly reduced the need for reminder letters.
Results showed that a 2-week suggested deadline without a planning tool led to the highest FIT return rate at 3 months (68.0%), compared with 66.0% in the control group. Conversely, the lowest return rate (63.2%) was seen among participants who received only the planning tool without any deadline.
The primary analysis, assuming independent effects of the two interventions, suggested a positive effect of giving a deadline (adjusted OR 1.13, 95% CI 1.08-1.19, P < .001), and no effect with use of the planning tool (aOR 0.98, 95% CI 0.94-1.02, P = 0.34). However, this was complicated by an interaction between the two interventions (P = .041).
Among participants who were given a deadline, there was no evidence that receiving a planning tool had any effect on CRC screening (aOR 1.02, 95% CI 0.97-1.07, P = 0.53), but without a deadline, giving the planning tool appeared to be harmful (aOR 0.88, 95% CI 0.81-0.96, P = .030). Secondary analyses indicated deadlines promoted earlier returns and significantly reduced the need for reminder letters.
Robb and colleagues noted that while the absolute increase in uptake with the deadline was modest (1.8%-2.0%), "adding a deadline to the invitation letter is a near zero-cost intervention delivered at national scale."
They continued: "We estimate that a 2% increase in FIT returns would mean an additional 39 000 people participating in a 2-year Scottish Bowel Screening round, with approximately 23 colorectal cancer deaths being avoided as a result."
As for study limitations, researchers acknowledged that they were unable to assess interactions based on ethnicity or determine the long-term impact of these interventions on future screening rounds.
Source: Robb KA, Young B, Murphy MK, et al. Behavioural interventions to increase uptake of FIT colorectal screening in Scotland (TEMPO): a nationwide, eight-arm, factorial, randomised controlled trial. Lancet. Published online March 12, 2025. doi:10.1016/S0140-6736(24)02813-7
