This multicenter study aims to evaluate clinical outcomes and optimize management strategies in patients with early colorectal cancer who undergo non-curative endoscopic resection.

Patients with non-curative resection following endoscopic treatment will be enrolled across multiple centers and managed according to real-world clinical decisions, including additional surgery or surveillance. Baseline demographic, endoscopic, and pathological characteristics will be systematically collected.

The primary objective is to compare recurrence and survival outcomes between different management strategies. Secondary objectives include identifying prognostic factors associated with recurrence and developing a risk stratification model to guide individualized treatment decisions.

All participants will undergo standardized follow-up according to clinical guidelines. This study is expected to provide real-world evidence to refine risk assessment, reduce unnecessary surgery, and improve personalized management for patients with early colorectal cancer after non-curative endoscopic resection.

Inclusion Criteria:

• Age ≥18 years;
• Patients with early colorectal cancer confirmed by histopathology;
• Patients who underwent endoscopic resection (including EMR, ESD, or equivalent techniques);
• Pathological diagnosis indicating non-curative resection, defined by the presence of at least one of the following: positive resection margin, submucosal invasion depth >1000 μm, poor differentiation, lymphovascular invasion, perineural invasion, or high-grade tumor budding;
• Availability of complete clinicopathological and follow-up data;
• Patients managed with either additional surgery or surveillance after endoscopic resection.

Exclusion Criteria:

• Patients with synchronous advanced colorectal cancer or distant metastasis at baseline;
• History of other active malignancies;
• Patients with inflammatory bowel disease, familial adenomatous polyposis, or other hereditary colorectal cancer syndromes;
• Patients who received neoadjuvant therapy before endoscopic resection;
• Incomplete pathological data or missing key variables;
• Loss to follow-up or follow-up duration less than 6 months.

This multicenter cohort study includes adult patients with early colorectal cancer who underwent non-curative endoscopic resection. Participants are stratified into additional surgery and surveillance groups based on post-resection management strategies. Comprehensive clinicopathological characteristics and follow-up data are collected to evaluate recurrence patterns, survival outcomes, and to develop and validate a risk prediction model.