Abstract
Despite the benefits of colorectal cancer (CRC) screening, participation compares
poorly to other screening programs. This study assessed the effectiveness of adding
different behavioral economic-based messages, to the invitation letter, to increase
uptake in the Cypriot CRC screening program. We performed two randomized
controlled trials. In the first trial (‘Trial 1’), 3212 individuals, aged 50 to 69 years, were
randomly allocated (1:1:1:1:1:1:1) to one of six intervention groups, or the control. The
intervention groups received the standard invitation letter received by the control, with
the addition of one of six messages based on the following behavioral economics
principles: (1) social responsibility, (2) anticipated regret, (3) financial opportunity costs
(of non-attendance), (4) benefit (of early detection), (5) scarcity effect (limited duration
of the offer) and (6) social norms. The second trial (‘Trial 2’) tested the most efficacious
message (social responsibility) against the control in a larger sample (N=3074). In both
trials, the primary outcome was uptake eight weeks after the screening invitation. In
trial 1, overall uptake was 20.6%. There were no significant differences between the
control and the intervention conditions for the overall sample or men (all p’s>0.05).
Highlighting the social consequences of cancer did, however, increase uptake rates
among women (25.6% vs. 17.1%, aOR 1.67; 95% CI 1.05-2.66, p=0.031). We,
therefore, tested this message in Trial 2. Uptake was similar to trial 1 with 20.7%
(intervention: 20.8% vs control: 20.6%) and there was no impact on overall or uptake of
men and women separately (all p’s>0.05).