The effect of different combinations of open invitations and timed appointments on breast screening attendance: service evaluation of invitation strategies in the NHS Breast Screening Programme

Background The NHS Breast Screening Programme invites eligible women using either a timed appointment letter (option to change), or an open invitation to make an appointment. Non-attenders receive a ‘Timed’ or ‘Open’ second invitation. NHS England commissioned a service evaluation to determine the effect of different combinations of timed and open invitations. Methods Seven services, selected to ensure adequate representation of diverse socio-economic, ethnic, urban/rural, and current uptake groups, participated. Women were individually quasi-randomised to four combinations of Open/Timed invitations. The primary outcome was 90-day attendance. Results 17,965 women (mean age 58 years, IQR: 47–69) invited from April-October 2023 were included. Attendance overall increased from 49.1% (95%CI 47.7–50.6%) for Open/Open to 67.9% (66.5–69.2%) for Timed/Timed. Attendance following Open/Timed or Timed/Open invitations was 60.0% (58.6–61.4%) and 64.7% (63.3–66.1%) respectively. The same pattern was observed across all deprivation quintiles. Attendance amongst the most deprived increased from 41.1% (38.2–44.1%; Open/Open) to 63.3% (60.6–66.2%; Timed/Timed), compared with 61.4% (57.6–65.2%) to 78.0% (74.5–81.4%) for the least deprived quintile. Conclusion Sending timed appointment invitations increases attendance at breast screening. This might have a larger impact in the most deprived areas. Findings informed NHS England on the most effective invitation methodologies from April 2025.