Rainbow of KIBOU project: Effectiveness of invitation materials for improving cancer screening rate using social marketing and behavioral economics approaches.

Studies to date have shown that individual invitation (call) and re-invitation (recall) are effective in improving cancer screening rate. Also, by dividing subjects into segments and sending unique messages to each segment, the cancer screening rate is further improved. However, this approach is not realistic in the local governments due to limited resources, so we used social marketing and nudge techniques to develop cancer screening recommendation materials that do not need to send separately. This study therefore aimed to verify the effect of these materials in the real world. We compared the cancer screening rates in municipalities within Japan that used the invitation materials we developed (colorectal, breast, lung, cervical and stomach cancer), with those from the previous year. In addition, the usefulness of the materials in the real world was examined multilaterally using RE-AIM framework (Reach, Effectiveness, Adaption, Implementation, Maintenance). From 2015 to 2018, 4.3 million residents (Reach) from 787 municipalities (Adaption) were sent invitation materials for cancer screening. Of 167 municipalities that were compared, 141 (83%) showed an increase in screening rate when our materials were used. Overall, the screening rate improved by 2.6% or 1.44 fold (p < 0.001) (Effectiveness). However, the screening rate varied greatly depending on how screening is provided. Of the four years studied, 75 municipalities used the same materials for two or more years (Implementation). The material developed in this study improved the cancer screening rate in the real world, and it may be possible to further improve the screening rate if the number of opportunities for screening and its capacity is increased at the timing of sending materials. The materials can be found on the website (http://rokproject.jp/kenshin/) and free electronic files are available to municipalities wishing to use them.