Reminder recall is associated with higher mammogram uptake among overdue repeat screeners: an exploratory telephone survey within a randomized trial

Despite more than two decades of a national breast cancer screening program, fewer than 40% of eligible women in Singapore undergo recommended biennial mammography. This study evaluated the effectiveness of screening reminders in promoting mammogram completion in a setting without routine reminders and examined the motivators, barriers, and perceptions influencing mammogram uptake, among women overdue for repeat screening. An exploratory, cross-sectional telephone survey was conducted from January to February 2025 as a sub-study nested within a randomized controlled trial (RCT) in a tertiary healthcare system in Singapore. The five-arm parent RCT enrolled 9,000 women aged 50–69 who were overdue for repeat mammography and randomized them in a 2:1:1:1:1 ratio, with all participants receiving a mailed reminder (MR) and three mobile-app push notifications (PN), while arms 2–5 received additional behavioural interventions including a voucher, lottery incentive, motivational video, or scheduling assistance. In the telephone survey conducted three-weeks post parent RCT completion, approximately 60 women per trial arm were contacted. The survey assessed recall of reminders and its association with mammogram scheduling and completion, as well as participants’ perceived motivators and barriers to screening. Of 2,941 unique calls made, 749 women (25%) were reached, of whom 303 (40%) completed the survey (median age 63 years). MR recall (50.2%) exceeded PN recall (34.0%; p < 0.001), with no demographic or arm-specific differences. MR recall was associated with higher rates of mammogram completion ( n = 40/152, 26.3%) compared with no MR recall ( n = 10/151, 6.6%; odds ratio 5.04; 95% CI: 2.41–10.51, p < 0.001). Key motivators for screening were awareness (51%), receipt of MR (24%), and social/physician recommendations (18.6%); barriers were scheduling conflicts (26%), prior appointments (24%), and low awareness (17%). MR recall was associated with higher mammogram uptake among overdue repeat screeners. Timely reminders, simplified scheduling, and close follow-up remain key to overcoming behavioural barriers to screening in high-access health systems. The trial was registered at ClinicalTrials.gov (NCT06733155).