Background Colorectal cancer is a significant health concern. For individuals identified as being at high risk for developing this disease, adopting healthy lifestyle behaviors is a powerful way to lower that risk. However, starting and maintaining these new habits can be challenging. This study aims to test a comprehensive support program designed to help high-risk individuals make and sustain these positive health behavior changes.

Purpose The main goal of this research is to see if a specially designed 12-week health promotion program can effectively help high-risk individuals improve their lifestyle (e.g., diet, exercise, smoking/alcohol use), increase their knowledge about colorectal cancer, and strengthen their confidence and motivation to stay healthy.

Study Groups Participants in this study will be randomly assigned (like flipping a coin) to one of two groups:

1. The Intervention Group: This group will take part in the 12-week health promotion program.
2. The Control Group: This group will receive general health information or standard care but will not participate in the special program.

Procedures The program for the Intervention Group includes:

• Educational Workshops: Five in-person group sessions to learn about cancer prevention, create personal health plans, and solve problems with others.
• Online Support: Regular health articles and tips sent through a private WeChat group.
• Daily Check-ins: Using the WeChat group for simple daily check-ins on exercise, fruit/vegetable intake, and smoking/alcohol use to build habit.
• Peer Support: Being paired with a "health buddy" and interacting with other participants for motivation.

All participants will be asked to complete several questionnaires at the beginning of the study, during the program, and after it ends (at 3 months) to measure their knowledge, beliefs, and lifestyle habits.

Duration The active program lasts for 12 weeks.

Potential Benefits Participants in the Intervention Group may benefit from improved health habits, a better understanding of how to reduce their cancer risk, and increased social support. Participants in the control group will receive general health information. If they wish, they will receive the same health materials and behavioral change intervention as the intervention group after the intervention concludes.

Inclusion Criteria:

• Meets the criteria for being at high-risk for colorectal cancer as defined by the US National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology for Colorectal Cancer Screening and the relevant Chinese expert consensus on colorectal cancer diagnosis and treatment.
• Age ≥ 18 years.
• Has normal verbal communication and comprehension abilities.
• Provides informed consent and voluntarily agrees to participate in the study.

Exclusion Criteria:

• Has a prior diagnosis of any malignancy (cancer).
• Has a diagnosed severe psychiatric or psychological disorder.

What IPD will be shared? Individual participant data that underlie the results reported in the primary and secondary publications after de-identification. This will include demographic data, baseline characteristics, and all outcome measure scores (e.g., HPLP-HRCP, CRC-KQ, CHBMS, MHLC, K10, PSSS).

When will IPD be available? Beginning 9 months after the publication of the main trial results and ending 36 months thereafter.

Who can access the IPD?? Researchers who provide a methodologically sound proposal for use in an independent ethical review-approved meta-analysis or replication study.

How can IPD be accessed? Proposals should be directed to the corresponding author via email. To gain access, requestors will need to sign a data access agreement. Data will be shared via a secure file transfer platform.

What other documents will be available? The study protocol, statistical analysis plan, and informed consent form will be made available on ClinicalTrials.gov alongside the results.