Development and Usability Evaluation of a Knowledge Graph-Based Symptom Management System for Patients With Breast Cancer Undergoing Chemotherapy

• Knowledge Graph-Based Symptom Management System (Behavioral): The intervention is a knowledge graph-based symptom management system designed for patients with breast cancer undergoing chemotherapy. The system integrates evidence-based guidelines, clinical expertise, and patient-reported data to generate personalized symptom management recommendations. Patients use the system to report symptoms and receive tailored management strategies. Nurses use the system to support clinical decision-making and provide symptom management guidance. The intervention aims to improve symptom management and support patient-centered care.

Primary outcomes

• mHealth App Usability Questionnaire [At the end of the study period (approximately 6-8 weeks after system use)]: System usability assessed using the System Usability Scale (SUS), a validated 10-item questionnaire evaluating overall usability of the system.
• Post-Study System Usability Questionnaire [At the end of the study period (approximately 6-8 weeks after system use)]: Usability of the knowledge graph-based symptom management system assessed using a standardized mHealth usability questionnaire, including ease of use, usefulness, and user satisfaction.

Secondary outcomes

• MD Anderson Symptom Inventory [At baseline and at the end of the study period (approximately 6-8 weeks after system use)]: Symptom severity and interference assessed using the MD Anderson Symptom Inventory (MDASI), a validated instrument measuring multiple symptoms in patients with cancer.
• Average session duration per use [Up to 12 weeks]: The average duration of each system use session per participant, recorded automatically via system logs.
• Number of system uses per week [Up to 12 weeks]: The number of times each participant accesses the system per week, recorded automatically via system logs
• Number of completed symptom reports [Up to 12 weeks]: The total number of symptom reports submitted by each participant through the system, recorded automatically via system logs.
• Semi-structured interviews (patient experience and satisfaction) [At the end of the study period (approximately 6-8 weeks after system use)]: Patient experience and satisfaction explored through semi-structured interviews, focusing on usability, perceived usefulness, and barriers to system use.
• Task-based usability assessment [Baseline]: Task-based usability assessment evaluating users' ability to complete predefined tasks, including task completion rate, time on task, and error rate.

Other outcomes

• Adverse events and safety monitoring [Throughout the study period (approximately 6-8 weeks)]: Adverse events and safety monitoring during the study period, including any physical discomfort, psychological distress, or other unintended effects related to system use. All adverse events will be recorded and reviewed by the research team, and participants with clinically concerning conditions will be referred to the clinical care team as appropriate.

Sex: All, ages: 18 Years to 80 Years

Inclusion Criteria:

* Aged 18 to 80 years
* Pathologically confirmed breast cancer
* Stage I-III breast cancer
* Planning to initiate or currently receiving neoadjuvant or adjuvant chemotherapy
* Expected to continue chemotherapy during the study period and complete at least two treatment time points/cycles
* Able and willing to provide informed consent
* Able to complete basic smartphone operations and system tasks independently or with guidance from the research staff

Exclusion Criteria:

* Recurrent or metastatic breast cancer (stage IV)
* Significant cognitive impairment or communication barriers that preclude informed consent or completion of study procedures
* Severe psychiatric disorders or unstable psychiatric symptoms that may interfere with study participation
* Considered unsuitable for participation by the clinical or research team because of unstable medical condition or need for acute management