AI-Assisted Patient Support in mHSPC

• The Same Platform without AI Agent (Behavioral): The basic platform supports study registration, assessments, and usage tracking but does not provide AI agent function during the first 2 weeks.
• AI Agent-Assisted Patient-Centered Support (Behavioral): Participants access the AI agent through a WeChat Mini Program. It provides clinician-reviewed educational materials on prostate cancer and disease management. A large language model-based AI agent provides real-time, multi-turn, personalized responses to participants' questions. Retrieval-augmented generation based on a curated clinical knowledge base is used to improve the accuracy and clinical relevance of the responses. The AI agent will not replace physician assessment, diagnosis, or treatment decision-making.
• Delayed AI Agent-Assisted Patient-Centered Support (Behavioral): Participants will receive access of AI agent after completing the 2-week assessments. The AI agent is accessible through a WeChat Mini Program. It provides clinician-reviewed educational materials on prostate cancer and disease management. A large language model-based AI agent provides real-time, multi-turn, personalized responses to participants' questions. Retrieval-augmented generation based on a curated clinical knowledge base is used to improve the accuracy and clinical relevance of the responses. The AI agent will not replace physician assessment, diagnosis, or treatment decision-making.
• Standard-of-Care Medical Treatment (Drug): Participants will continue to receive standard-of-care medical treatment for mHSPC throughout the study. Treatment may include androgen deprivation therapy (ADT) in combination with an androgen receptor pathway inhibitor (ARPi), and bone-protective agents may also be administered, as determined by the treating physician according to clinical guidelines and individual patient needs. However, radiotherapy, surgery, or chemotherapy in any form is not permitted during the study period. Non-antineoplastic medications taken prior to enrollment may be continued during the study.

Primary outcomes

• Between-Group Difference in Change from Baseline in GAD-7 Total Score at 2 Weeks [At baseline and 2 weeks after randomization.]: The Generalized Anxiety Disorder-7 (GAD-7) scale assesses anxiety symptoms using 7 items, each scored from 0 to 3. The total score ranges from 0 to 21, with higher scores indicating greater anxiety severity. Change from baseline is calculated as the score at 2 weeks minus the baseline score, with a negative change indicating improvement. The mean change from baseline will be compared between the two groups.

Secondary outcomes

• Between-Group Difference in Disease Knowledge Test Total Score at 2 Weeks [At 2 weeks after randomization.]: The study-specific Disease Knowledge Test consists of 10 objective questions on mHSPC. Each correct answer is scored as 1, and each incorrect or unknown answer is scored as 0. The total score ranges from 0 to 10, with higher scores indicating greater disease knowledge. The mean total score at 2 weeks will be compared between the two groups.
• Between-Group Difference in Change from Baseline in the Brief Illness Perception Questionnaire (B-IPQ) Total Score at 2 Weeks [At baseline and 2 weeks after randomization.]: The Brief Illness Perception Questionnaire (B-IPQ) assesses cognitive and emotional representations of illness. Eight scored items are rated from 0 to 10. After appropriate reverse scoring, the total score ranges from 0 to 80, with higher scores indicating a more threatening perception of the illness. Change from baseline is calculated as the score at 2 weeks minus the baseline score, with negative values indicating improvement. The mean change from baseline will be compared between the two groups.
• Between-Group Difference in Change from Baseline in the Insomnia Severity Index (ISI) Total Score at 2 Weeks [At baseline and 2 weeks after randomization.]: The Insomnia Severity Index (ISI) assesses insomnia severity using 7 items, each scored from 0 to 4. The total score ranges from 0 to 28, with higher scores indicating greater insomnia severity. Change from baseline is calculated as the score at 2 weeks minus the baseline score, with negative values indicating improvement. The mean change from baseline will be compared between the two groups.
• Between-Group Difference in Change from Baseline in the Patient Satisfaction Questionnaire-18 (PSQ-18) Score at 2 Weeks [At baseline and 2 weeks after randomization.]: The Patient Satisfaction Questionnaire-18 (PSQ-18) consists of 18 items assessing satisfaction with medical care across seven domains. Each item is scored from 1 to 5. After appropriate reverse scoring, the item scores are summed to produce a total score ranging from 18 to 90, with higher scores indicating greater patient satisfaction. Change from baseline is calculated as the score at 2 weeks minus the baseline score, with positive values indicating improvement. The mean change from baseline will be compared between the two groups.

Other outcomes

• Between-Group Difference in Change from Baseline in GAD-7 Total Score at 4 Weeks [At baseline and 4 weeks after randomization.]: The Generalized Anxiety Disorder-7 (GAD-7) scale assesses anxiety symptoms using 7 items, each scored from 0 to 3. The total score ranges from 0 to 21, with higher scores indicating greater anxiety severity. Change from baseline is calculated as the score at 4 weeks minus the baseline score, with a negative change indicating improvement. The mean change from baseline will be compared between the two groups. This exploratory comparison reflects the effects of the two access strategies.
• Accuracy of LLM-Generated Answers to Participant Questions [During the 4-week study period.]: Participant questions and the corresponding answers generated by the LLM-based AI agent will be collected. Each answer will be independently reviewed for accuracy by two urologic oncology physicians. In cases of disagreement, a third urologic oncology expert will make the final determination. Accuracy will be calculated as the proportion of evaluable answers classified as accurate.

Sex: Male, ages: 18 Years to 80 Years

Inclusion Criteria:

1. Newly diagnosed prostate adenocarcinoma confirmed by histopathology or cytopathology;
2. Metastatic disease confirmed by imaging or pathology;
3. Diagnosis of metastatic prostate cancer within 2 weeks before enrollment;
4. Aged 18-80 years;
5. A GAD-7 score of 5 or higher at screening;
6. Adequate cognitive ability to understand and participate in the study;
7. Adequate language comprehension and ability to complete the study questionnaires independently;
8. Access to a smartphone and an internet connection required to use the study platform;
9. Provision of written informed consent.

Exclusion Criteria:

1. An acute or unstable psychiatric disorder, such as severe depressive or anxiety disorder, or severe insomnia requiring urgent specialist care;
2. History of or current cognitive impairment, such as intellectual disability or Alzheimer's disease;
3. A requirement for emergency surgery within 72 hours after enrollment;
4. Planned prostate cancer-directed radiotherapy, surgery, or chemotherapy during the study period;
5. Current participation in another interventional clinical trial;
6. A request from the participant's family to withhold the diagnosis or disease-related information from the participant.