Agentic AI App and Home Bioimpedance Monitoring for Endocrine Therapy Adherence and Lymphedema in Breast Cancer Survivors (Pinkmate)

Participants receive the Pinkmate mobile app with active electronic patient-reported outcomes (ePRO) and Agentic AI monitoring. Patients complete weekly ePRO questionnaires. In addition, reporting adverse symptoms (e.g., fatigue, arthralgia) to the conversational AI chatbot immediately triggers targeted in-depth ePRO assessments. When symptom scores worsen beyond predefined thresholds, the patient is automatically flagged on the clinician dashboard. Clinical staff review the dashboard daily (business days) and conduct proactive telephone consultations within 48 hours to provide supportive care, symptom relief education, medication adherence counseling, and expedited clinic referrals.

Closed-access mobile health application (Pinkmate) featuring an Agentic AI conversational chatbot and electronic patient-reported outcomes (ePRO) module. Participants complete weekly ePRO symptom surveys. In addition, adverse symptom complaints during chatbot interactions automatically trigger targeted in-depth ePRO questionnaires. Worsening symptoms beyond predefined thresholds generate alert flags on the clinician web dashboard. Clinical staff monitor the dashboard daily (business days) and conduct proactive telephone consultations within 48 hours of an alert to provide supportive care, symptom relief education, medication counseling, or expedited clinic referrals.

• Pinkmate App

Participants use the Pinkmate mobile app limited to basic medication reminders, daily check-in logs, and quarterly ePRO surveys (every 3 months) aligned with routine outpatient visit schedules. Conversational AI chatbot-triggered questionnaires, automated clinician dashboard alert flagging, and proactive 48-hour telephone intervention by medical staff are disabled. Symptoms and medication adherence are managed during routine in-person outpatient clinic visits according to standard care.

Participants utilize the Pinkmate mobile application with functionality limited to basic medication reminders, daily adherence check-ins, and quarterly (every 3 months) ePRO questionnaires aligned with scheduled outpatient clinic visits. Automated conversational AI chatbot symptom triggers, clinician dashboard alert flags, and proactive 48-hour telephone consultations are disabled. Adverse symptom evaluation, medication counseling, and management are conducted during routine in-person outpatient clinic visits according to standard clinical practice.

• Standard care with basic Pinkmate app

Breast cancer patients who underwent ALND (including newly operated patients and prior ALND patients without clinical lymphedema) are loaned a home bioimpedance analyzer (InBody BWA ON, loaned until Dec 31, 2028). Patients perform self-measurements at home at least twice weekly (daily recommended; on waking, post-voiding) linked to the Pinkmate app. Persistent dashboard alerts (affected-arm ΔECW/TBW ≥ 0.010 or interlimb ratio ≥ 1.020 for 3 days) trigger clinical staff phone calls within 48 hours for self-care reinforcement and early clinic visits. Participants also utilize app-based AI lifestyle coaching and fluid tracking graphs. In-clinic InBody 770 and circumference tape measurements are performed at routine visits.

Participants receive a loaned portable multi-frequency bioelectrical impedance analyzer (InBody BWA ON; MFDS License No. 19-4025; loaned until December 31, 2028). Patients perform self-measurements at home under standardized morning post-voiding conditions at least twice weekly (daily recommended). Data are transmitted via Bluetooth to the Pinkmate app and clinician dashboard. Persistent bioimpedance alerts (affected-arm ΔECW/TBW ratio ≥ 0.010 from baseline or interlimb ratio ≥ 1.020 for 3 consecutive days) trigger medical staff telephone counseling within 48 hours for self-care reinforcement and early clinic visits. Participants also utilize app-based AI lifestyle coaching and arm fluid tracking graphs. In-clinic InBody 770 measurements are performed at routine visits.

• InBody BWA ON (MFDS License No. 19-4025)

Breast cancer patients who underwent ALND do not receive the home InBody BWA ON device and use the Pinkmate app solely for educational self-care content and scheduled surveys. Continuous home bioimpedance data linkage and real-time dashboard alerts are disabled. Limb volume and bioimpedance are evaluated exclusively during scheduled outpatient visits using in-clinic InBody 770 and circumference tape measurements. Standardized rehabilitation therapy upon meeting criteria for subclinical or clinical lymphedema is administered identically to the experimental arm.

Participants do not receive the home InBody BWA ON device and use the Pinkmate mobile application solely for educational self-care content and scheduled surveys. Continuous home bioimpedance data linkage and real-time dashboard alert flagging are disabled. Arm swelling and segmental bioimpedance are evaluated exclusively during routine outpatient visits (at 3, 6, 12, 24, 36, and 60 months) using the in-clinic InBody 770 analyzer (MFDS License No. 13-1188) and circumference tape measurements. Standardized rehabilitation therapy upon meeting predefined criteria for subclinical or clinical lymphedema is administered identically to the experimental arm.

• Standard surveillance with InBody 770 (MFDS No. 13-1188)

PDC is defined as the percentage of days during the evaluation period that the participant actually took prescribed adjuvant endocrine therapy (tamoxifen or aromatase inhibitors). It is calculated from prescription records and daily in-app medication check logs: PDC = (Number of days medication taken / Total observation days) × 100. Mean PDC and the proportion of participants achieving PDC ≥ 80% are compared between arms.

Limb volume is derived from bilateral upper limb circumferences measured every 4 cm starting 2 cm below the axilla down to the wrist using a standardized tape measure (mean of two measurements). Volume is calculated using the truncated cone formula. The relative percentage change in affected upper limb volume from baseline to 6 months post-enrollment is compared between arms.

Segmental extracellular water-to-total body water ratio (ECW/TBW) of the affected upper limb is measured using the in-clinic multi-frequency bioelectrical impedance analyzer (InBody 770). The change in affected-arm ECW/TBW ratio from baseline to 6 months post-enrollment (ΔECW/TBW) is compared between arms.

PDC is calculated as the percentage of days covered by prescribed adjuvant endocrine therapy at each follow-up time point, analyzed over time across arms using a linear mixed model (LMM).

Quality of life is assessed using the Korean version of FACT-B (Version 4). Total score ranges from 0 to 148, with higher scores reflecting better breast cancer-specific health-related quality of life.

Standardized ePRO symptom T-scores for key endocrine therapy-associated adverse symptoms (including fatigue and arthralgia) collected via the mobile application.

Proportion of participants developing subclinical lymphedema (affected-arm volume increase ≥ 5% to < 10% or InBody 770 ΔECW/TBW ≥ 0.010) or clinical lymphedema (affected-arm volume increase ≥ 10% or InBody 770 ECW/TBW ≥ 0.395).

Proportion of participants experiencing progression from ISL Stage 1 to Stage 2 or higher based on clinical evaluation by a rehabilitation medicine specialist.

Patient-evaluated usability of the Pinkmate mobile health application using the System Usability Scale (SUS). Total score ranges from 0 to 100, where higher scores indicate greater usability and satisfaction.