Optimizing Texting Interventions for Melanoma Prevention and Early Detection: A Latin Square Crossover RCT

Introduction: Text messaging is an effective way to reach large populations with health promotion support. This study aims to establish the optimal text messaging intervention to achieve behavior change in young adults at risk of skin cancer. Study Design: Latin square crossover RCT. Setting/participants: Participants were women and men aged 18–40 years living in Queensland, Australia who owned a smartphone and had ≥2 skin cancer risk factors. Intervention: Participants were enrolled from December 2018 to February 2019 and completed an eligibility survey. Eligible participants were randomized to 4 different text message interventions using a Latin square design with varying personalization, interactivity, and message frequency (February 2019‒July 2019). Each intervention lasted for 1 month; between interventions, participants had a 1-week washout period in which they completed an online questionnaire. Participants completed a 6-month follow-up online survey in January 2020. Main outcome measures: Measures included self-reported sun protection habits and sunburns. Results: A total of 277 (71.2% response rate) participants completed the 6-month follow-up. The sun protection habits index was significantly higher in all the 4 text messaging interventions (p<0.01 for each intervention) than at baseline, with similar sun protection habits improvements among all interventions (p=0.27). Sunburn rates decreased significantly over time (p<0.01 each intervention), with all the 4 interventions achieving reductions in sunburn rates during the intervention periods (p=0.78). Overall, the sunburn rates decreased from 40.3% at baseline to 7.0% at the end of the intervention, and at 6-month follow-up, it remained significantly below baseline levels at 23.5% (p<0.01). Conclusions: Regular text messaging interventions result in significantly increased sun protection and decreased sunburn in young adults. Trial registration: This study is registered at the Australian and New Zealand Clinical Trials Registry ACTRN12618001299291.