This study aimed to investigate the efficacy of vitamin B1 in patients with familial adenomatous polyposis, and to determine the inhibitory effect of vitamin B1 on the size and number of colorectal adenomas by administering oral vitamin B1 therapy for 1 year and colonoscopy follow-up every 3 months

The investigators will mark a region with a diameter of no more than 5 cm, containing at least 3 polyps, each with a diameter of 5-15 mm. Continuous video recording will be conducted throughout the colonoscopy procedure to provide baseline reference images of the colorectal polyps. Patients with familial adenomatous polyposis were given 100mg bid dose of vitamin B1 orally for one year, and colonoscopies were followed every 3 months to observe changes in the size and number of polyps in the designated area.

Inclusion Criteria

1. Patients with a confirmed diagnosis of classical familial adenomatous polyposis (FAP) based on colonoscopy, histopathology, and genetic testing.
2. Aged between 18 and 80 years, with no restriction on gender.
3. No history of total colectomy, with remaining bowel segments available for evaluation.
4. Presence of more than 10 adenomatous polyps in the colon or rectum.
5. Normal liver and kidney function.
6. Willing to participate in vitamin B1 therapy and commit to regular follow-up appointments.

Exclusion Criteria

1. Use of medications for more than one week in the past three months, or inability to avoid continuous use during the study period, that may affect colorectal polyps, including aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), ω-3 polyunsaturated fatty acids, rapamycin, and curcumin.
2. Use of medications for more than one week in the past three months, or inability to avoid continuous use during the study period, that may affect vitamin B1 absorption, metabolism, or excretion, including aminoglycoside antibiotics, thiazide diuretics, oral contraceptives, antiepileptic drugs, and antituberculosis drugs.
3. Attenuated familial adenomatous polyposis (AFAP).
4. Allergy to vitamin B1.
5. Contraindications to vitamin B1, such as liver or kidney dysfunction, or severe neuropsychiatric disorders.
6. History of total colectomy, with no remaining bowel segments.
7. Pregnant or breastfeeding individuals.
8. Presence of advanced colorectal cancer or metastatic cancer in other locations.
9. Previous radiotherapy, chemotherapy, or tumor immunotherapy.
10. History of alcohol or other substance abuse.

Original data could be shared at request by email after publication

The data will be available after publication of the study

The shared data could be available by contacting Dr. Xin-Yang Liu at liu.xinyang@zs-hospital.sh.cn.