Trial to Evaluate the Impact of Various Pragmatic Interventions to Increase Mammography Uptake Among Defaulted Repeat Screeners in Singapore (REMIND1)

Randomized Controlled Trials to Evaluate Outreach Strategies for Increasing Mammogram Uptake in Singaporean Women Who Are Defaulted Repeat Screeners

Breast cancer is the most common cancer among women in Singapore, accounting for nearly 30% of all female cancers. While regular biennial mammography can reduce mortality, screening rates in Singapore remain low at 34.7%; well below the 70% threshold required for population-level impact. Despite a national screening program in place since 2002, uptake continues to be hindered by psychological, cultural, and logistical barriers. Although various studies have explored different behavioural interventions to boost mammogram uptake; ranging from reminders (traditional mailers, phone calls, text messages) and education to financial incentives, their effectiveness varies by population and context. Furthermore, few large-scale, prospective studies have been conducted locally. Prior research in Singapore is either outdated or limited in scope, and there is a particular lack of rigorous trials evaluating behavioral interventions tailored to women who have defaulted on screening, who faces distinct psychological and behavioral barriers; ranging from low perceived risk and fear, to false reassurance from prior normal results or lack of reminders, or had bad experience (procedural pain or prior false positive results) during last mammogram. Engaging these women is critical, yet challenging, and failure to do so undermines efforts to achieve broad population coverage.

The REMIND Study addresses this critical gap by evaluating five pragmatic and scalable outreach strategies to increase mammogram uptake among women who had their last screening more than 2 years ago and are currently overdue. Through a large, randomized controlled trial, the study will generate much-needed local evidence on what works to reengage these women. Findings will directly inform national screening policies and the design of future outreach efforts tailored to Singapore's diverse population.

Study Overview

• Status: Enrolling by invitation
• Conditions: Breast Cancer; Breast Neoplasm; Early Detection of Cancer; Mammography Screening; Mammogram Uptake; Early Breast Cancer Detection
• Intervention / Treatment: Behavioral: Arm 2: One mailed reminder; Behavioral: Arm 4: Mailed reminder with prescheduled appointment; Behavioral: Arm 3: Two mailed reminders; Behavioral: Arm 5: Mailed reminder

Detailed Description

The REMIND Study is a five-arm randomized controlled trial (RCT) designed to evaluate the effectiveness of a few behavioral interventions to increase mammogram uptake among women aged 50-69 years who have defaulted on mammogram screening. The study's specific aim is to identify effective, affordable, and scalable behavioral interventions that can be implemented in Singapore's general population to improve participation in surveillance mammography. This is a minimal-risk, population-based study that does not require participant visits or in-person interaction, except for a subset involved in a follow-up telephone survey.

Eligibility Criteria: Singaporean women, aged 50-69, who are eligible for free biennial mammograms, with no history of prior breast cancer, have had at least one mammogram before, but not screened in the past 2 years will be will be identified using the NUH electronic medical health records system (EPIC). We will restrict the selection to NUHS patients who are registered users of the NUHS App. To further select/narrow down the eligible participants app activity or last log in date will be used. Patients who signed up the NUHS App have all consented to receive push notifications on research studies. There are over 600,000 registered users of NUHS App. The required 12,750 patients for the study will be randomly selected from these eligible patients.

Randomization and Intervention Arms: A total of 12,750 eligible women will be randomly assigned in equal proportions (n=2,550 per arm) to one of the following five groups:

1. no intervention (control);
2. standard mailed reminder (MR);
3. MR plus a second MR sent four weeks later;
4. MR with a pre-scheduled mammogram appointment; and
5. MR containing behavioral nudge messaging (e.g., social norm or gain or loss framing techniques).

Randomization will be computer-generated. NOTE: Arm 1 represents the current standard practice at NUHS, where patients are not routinely invited or reminded to attend mammogram screenings.

Women in intervention arms 2-5 will receive their respective outreach materials by post (personalized mailers on NCIS letter head) as well as push notifications via the NUHS app. 5-7 days after the mailers are sent, 1st batch of PN will be sent. Up to three batches of PN will be sent to all participants in Arms 2-5, 3 weeks apart. The push notifications will either be linked to a microcontent landing page or a webpage on NCIS website. The content of the mailers and landing page/ webpage will be the same explaining the importance of regular mammography, tailored messages according to each intervention type, and relevant booking instructions or appointment details. These materials have been designed to reflect evidence-based behavioral science strategies and were co-developed in consultation with clinicians, behavioural science experts, and community stakeholders. Participants in the control arm (Arm 1) will not receive any intervention.

This is a minimal-risk study. There are no in-person visits, clinical procedures, or additional tests required. Participation primarily involves receiving reminders. Women may choose to opt out of the study at any time.

Outcome measurement: All data on mammogram completion will be obtained from existing sources such as electronic medical records and the national screening registry. The primary outcome is mammogram uptake within four months of the first intervention (date of sending the mailer/ push notification, which ever is later). In addition to the primary time point, mammogram uptake data may also be extracted at the 6-month and 12-month marks following the intervention. These extended follow-up points will allow for the assessment of any delayed uptake, which may help to understand the longer-term impact of the interventions. No new clinical data will be generated from participants.

NOTE: To avoid a huge surge in calls to the appointment booking hotline number, mailers will be sent in a staggered manner over 4-12 weeks. Hence, the collection of mammogram completion data will also be staggered and will be 4 months from the day of sending the mailers/PNs which ever is the later. Similarly, for the participants in Arm 4 (mailer reminder with pre-scheduled appointment), the mailers/PN will be sent out 4-6 weeks prior to the appointment date and the mammogram completion date will be calculated four months from the date the mailer/PN was sent.

Post-trial telephone survey: In addition post-trial, a subset of participants from Arms 2-5, will be randomly selected to participate in a telephone survey aimed at understanding motivations, barriers, and perceptions related to the interventions and screening. Participants will be randomly selected and contacted until a total of up to 70 participants in each arm responds and takes part in the survey. About 3-8 weeks post trial, the participants will be contacted via phone, and verbal consent will be obtained prior to initiating the survey. They will be informed that the survey will take about 5-10 minutes, their participation is voluntary, they may skip any question or withdraw at any time, and their responses will remain confidential. Trained research staff will be performing the telephone survey.

• Study Type: Interventional
• Enrollment (Estimated): 12750
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Singapore
  • Singapore, Singapore
    • National University Hospital Singapore

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Singaporean citizen
• Age 50-69
• Registered as a patient at the National University Hospital
• Registered and active user of NUHS App
• Signed up with Healthier SG with a primary care provider within the NUHS Primary Care Network
• Must be defaulted repeat screeners : Must have done one prior mammogram screening but not in the past 2 years

Exclusion Criteria:

• Diagnosis of breast cancer in EPIC
• Mammogram done in the past 24 months in EPIC

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm 5: Mailed reminder with enhanced messaging; Receives mailed reminder with enhanced messaging	Behavioral: Arm 5: Mailed reminder; Receives one mailed reminder with enhanced messaging motivating recipient to undergo screening
No Intervention: Control Arm (Arm 1); Does not receive any reminder to go for mammogram
Experimental: Arm 2: One mailed reminder; Receives a single mail reminder	Behavioral: Arm 2: One mailed reminder; Receives a mailed reminder with basic information about breast cancer and instructions on scheduling a mammogram
Experimental: Arm 3: Two mailed reminders; Receives two mail reminders, 4 weeks apart	Behavioral: Arm 3: Two mailed reminders; Receives a mailed reminder + follow-up mailed reminder, 4 weeks after the first
Experimental: Arm 4: Mailed Reminder with Prescheduled Appointment; Receives a mailed reminder with prescheduled appointment	Behavioral: Arm 4: Mailed reminder with prescheduled appointment; Receives one mailed reminder with a pre-scheduled appointment, with instructions to change appointment

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of proportion of participants completing surveillance mammography within 4 months after intervention assignment between interventional arms (2-5) and control arm (Arm 1)	The proportion of women who undergo surveillance mammography within 4 months of receiving the study intervention/reminder will be compared between Arm 1 (control) and Arms 2-5. Mammogram completion will be confirmed through electronic medical records. Results will be reported as the percentage of participants completing mammography in each study arm. Unit of Measure: Percentage of participants (%)	4 months from the time participants receive the intervention/reminder

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mammogram uptake at 6 and 12 months post-trial	Comparison of mammogram completion 6 and 12 months after the initial study	6 and 12 months from the time participants received the first mailed reminder
Association between participant characteristics and completion of surveillance mammography within 4 months	Multivariable logistic regression will be used to evaluate the association between participant characteristics and mammogram completion within 4 months after intervention. Covariates include age, race, housing type, and duration overdue for screening. Results will be reported as adjusted odds ratios with 95% confidence intervals.	4 months from the time participants receive the intervention/reminder
Post-trial telephone survey	A post-trial telephone survey of about 280 participants will gather insights into their response to the interventions. The study aims to provide actionable insights into effective, scalable interventions to improve mammography uptake and reduce breast cancer mortality in Singapore.	1-2 months post-trial

Collaborators and Investigators

• Sponsor: National University Hospital, Singapore

Study record dates

Study Major Dates

• Study Start (Actual): March 9, 2026
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: May 21, 2026
• First Submitted That Met QC Criteria: June 10, 2026
• First Posted (Actual): June 16, 2026

Study Record Updates

• Last Update Posted (Actual): June 16, 2026
• Last Update Submitted That Met QC Criteria: June 10, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: early detection; Breast cancer; Breast cancer detection; Mammography; Cancer Screening; Behavioural Intervention; Mailed reminder
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: 2025-0790

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No