An SMS and animated video intervention to increase uptake of breast cancer screening: a randomised controlled trial

Breast cancer screening attendance in the UK has fallen, and London has the lowest uptake nationally. This study tested the impact of a behavioural science-informed reminder SMS, and animated video intervention on screening uptake.This three-armed randomised controlled trial took place in two screening services in London (each service operated across a range of static sites such as hospitals, and mobile sites). We included participants who were registered with GP as female, aged 50-70 years, and not screened in the past 3 years. We excluded those who had opted out of screening messages or were in care. Participants were assigned into three groups via the final two digits of their NHS number (ratio 34:33:33): control group (received usual care reminder), behavSMS group (behavioural science-informed SMS reminder addressing reducing negative emotions and information on health consequences), or behavSMS+video group (behavioural SMS plus link to animation). Researchers were masked to allocation. The SMS and video were co-designed with stakeholders using the Behaviour Change Wheel. Invitation processes changed during the COVID-19 pandemic, and therefore, we did separate analyses for those receiving a timed appointment (n=9027), and an open invitation to book an appointment (n=25 020). Messages were sent 7 days and 1 day before the appointment, plus 7 days after the open invitation letter. Group differences in the primary outcome of attendance within 3 months of invitation (and secondary outcome of booking for open invites) were assessed using χ2, and logistic regression controlling for age, ethnicity, deprivation, and first invitation. This trial is registered with ClinicalTrials.gov, NCT05395871.Recruitment took place between July 18, and Oct 21, 2022. For timed invitations, 3094 participants were assigned to the control group, 2952 to the behavSMS group, and 2981 to the behavSMS+video group. For open invitations groups sizes were 8654, 8095, and 8271 respectively. Median age was 59 years for participants who received a timed appointment, and 58 years for those who received an open invitation. There were no attendance differences for timed appointments (intention-to-treat analysis): 71·9% (2225/3094) in control group; 69·9% (2064/2952) in behavSMS group; 71·7% (2137/2981) in behavSMS+video group (χ2(2)=3·47, p=0·176), even when controlling for covariates. There were no attendance differences for open invitations either: 7·4% (4104/8654) in control group, 8·3% (3909/8095) in behavSMS group, 48·1% (3978/8271) in behavSMS+video (χ2(2)=1·40, p=0·497), including when controlling for covariates. However, in the per-protocol analysis (of those with valid mobile numbers), intervention groups were more likely to book an appointment: 44·7% (3238/7274) in control group, 46·3% (3121/6744) in behavSMS group, and 46·3% (3199/6910) in behavSMS+video group (χ2(2)=6·01, p=0·050).Despite positive stakeholder feedback during co-design, the SMS or SMS+video interventions did not increase breast screening attendance compared with the usual SMS reminder. A limitation is that only 5·8% participants followed the video link. Links within SMS are unlikely to be an effective way to disseminate video content, and alternative options are being explored.NHS England and National Institute for Health and Care Research (NIHR).