Inclusion Criteria:
Outpatients undergoing colonoscopy at Renji Hospital who meet the following criteria:
1. Aged 18-75 years;
2. Had at least one but no more than six histologically confirmed colorectal adenomas (including tubular, tubulovillous, and villous adenomas) removed within 6 months prior to enrollment;
3. Provide informed consent for this study and are able to comply with the requirements for collecting qualified stool specimens, peripheral blood specimens, and providing relevant lifestyle and medical history information.
Healthy subjects who meet the following criteria:
1. Aged 18-75 years;
2. Have undergone colonoscopy within 6 months prior to enrollment with no histologically confirmed colorectal adenomas (including tubular, tubulovillous, and villous adenomas);
3. Provide informed consent for this study and are able to comply with the requirements for collecting qualified stool specimens, peripheral blood specimens, and providing relevant lifestyle and medical history information.
Exclusion Criteria:
The following outpatients undergoing colonoscopy at Renji Hospital:
1. Incomplete resection of adenoma during colonoscopy;
2. Individuals at high risk for hereditary colorectal cancer;
3. Regular use of aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), COX-2 inhibitors, calcium, or vitamin D (defined as daily intake of ≥100 mg aspirin and ≥1200 mg calcium for at least 3 months);
4. History of subtotal gastrectomy, total gastrectomy, or partial enterectomy;
5. History of severe cardiac, hepatic, renal disease, or cancer;
6. Severe constipation or psychiatric disorders;
7. Pregnant, breastfeeding, or planning to become pregnant;
8. Undergone colonoscopy with inadequate bowel preparation (rated as "poor" or "insufficient" according to the Aronchik scale) or short observation time (withdrawal time \<6 minutes).
9. Use of antibiotics, probiotics, or prebiotics within 1 month prior to enrollment.
The following healthy subjects:
1. Individuals at high risk for hereditary colorectal cancer;
2. Regular use of aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), COX-2 inhibitors, calcium, or vitamin D (defined as daily intake of ≥100 mg aspirin and ≥1200 mg calcium for at least 3 months);
3. History of subtotal gastrectomy, total gastrectomy, or partial enterectomy;
4. History of severe cardiac, hepatic, renal disease, or cancer;
5. Severe constipation or psychiatric disorders;
6. Pregnant, breastfeeding, or planning to become pregnant;
7. Undergone colonoscopy with inadequate bowel preparation (rated as "poor" or "insufficient" according to the Aronchik scale) or short observation time (withdrawal time \<6 minutes).
8. Use of antibiotics, probiotics, or prebiotics within 1 month prior to enrollment.
