WhatsApp Chatbot Outreach Improves CRC Screening Uptake

Clinical Summary

• Prospective, open-label, 2-arm RCT: 500 asymptomatic Hong Kong adults aged 50–75 eligible for government CRC screening and using WhatsApp; randomized 1:1 to chatbot outreach or standard text reminder.
• Intention-to-treat FIT uptake favored chatbot outreach at 3 months (36.0% vs 27.6%; P=.043) and 6 months (45.6% vs 36.4%; P=.045), but not 1 month (22.4% vs 19.6%; P=.509).
• Chatbot education, risk assessment, and screening-navigation information may support FIT completion; applicability is limited to this open-label, WhatsApp-accessing Hong Kong population. No confidence intervals or next-step recommendations were reported.

A theory-based WhatsApp chatbot outreach intervention significantly increased fecal immunochemical test (FIT)–based colorectal cancer (CRC) screening uptake compared with a standard text reminder, with benefits emerging at 3 months and persisting through 6 months in a randomized controlled trial conducted in Hong Kong.

Lam and colleagues conducted a prospective, open-label, 2-arm randomized controlled trial involving asymptomatic adults aged 50 to 75 years who were eligible for Hong Kong’s government-organized CRC screening program and had access to WhatsApp Messenger. A total of 500 participants were randomized 1:1 to WhatsApp chatbot outreach (WCO) or a standard text reminder (STR), with 250 participants in each group. The mean participant age was 61.8 years, and approximately one-third were male.

Participants could receive a CRC education video, personalized risk assessment, and district-specific information on participating primary care physicians and how to arrange screening. By comparison, the STR group received a general text reminder and a link to the government screening program website. 

The primary outcome was FIT screening uptake at 3 months, defined as completing the organized screening program by returning a valid FIT kit. Secondary outcomes included screening uptake at 1 and 6 months.

In intention-to-treat analyses, FIT uptake at 3 months was significantly higher with WCO than STR (36.0% vs 27.6%; P=.043). The difference persisted at 6 months, when uptake reached 45.6% in the WCO group compared with 36.4% in the STR group (P=.045). No significant between-group difference was observed at 1 month (22.4% vs 19.6%; P=.509). Per-protocol analyses produced similar findings.

The investigators noted that the delayed separation between groups may reflect the time required for participants to progress from considering screening to taking action, while the chatbot’s practical navigation features may have helped reduce barriers to completing FIT screening.

Reference 

Lam TYT, To Z, Wang ZJ, et al. Effectiveness of theory-based WhatsApp chatbot outreach in colorectal cancer screening uptake: a randomized controlled trial. Clin Gastroenterol Hepatol. Published online 2026. doi:10.1016/j.cgh.2026.08.