Effectiveness of Theory-Based WhatsApp Chatbot Outreach in Colorectal Cancer Screening Uptake: A Randomized Controlled Trial

BACKGROUND & AIMS: Colorectal cancer (CRC) screening effectively reduces both the incidence and mortality associated with CRC. However, despite the growing implementation of organized screening programs, uptake rates remain suboptimal worldwide. We aim to evaluate the effectiveness of a novel, theory-based WhatsApp chatbot outreach (WCO) intervention in improving the CRC screening uptake rate compared with a standard text reminder (STR). METHODS: We conducted a prospective, open-label, 2-arm, parallel, randomized controlled trial in a community setting. Asymptomatic individuals aged 50-75 years with access to WhatsApp Messenger were recruited and randomized to the WCO or STR group on a 1:1 basis. The WCO delivered a health education video and a personalized risk assessment tailored to participants' stages of change based on the transtheoretical model. Additionally, it provided practical information on where and how to access screening services. The STR was a single text reminder with an organized screening program website link. The primary outcome, the CRC screening uptake rate, was assessed at 3 months. Secondary outcomes were 1- and 6-month uptake rates. RESULTS: From July to October 2024, 500 participants were recruited and randomized. Their baseline characteristics were similar between groups. The CRC screening uptake rate was significantly higher in the WCO group than in the STR group at 3 months (36% vs 27.6%; P = .043). This difference remained at 6 months (45.6% vs 36.4%; P = .045), whereas the uptake rate was similar between groups at 1 month. CONCLUSIONS: The WCO intervention improved CRC screening uptake at 3 months, with supportive findings at 6 months. CLINICALTRIALS: gov, Number: NCT06192862.