Oral B-Complex Vitamin (B6, B9 and B12) Prevents Low Anterior Resection Syndrome in Rectal Cancer Patients With Hyperhomocysteinemia - NCT07928180

The goal of this clinical trial is to investigate if taking Oral B-Complex Vitamin (B6, B9 and B12) can help prevent low anterior resection syndrome (LARS) in rectal cancer patients with hyperhomocysteinemia after sphincter-preserving surgery for rectal cancer. LARS is a group of bowel problems that can occur after rectal cancer surgery, including frequent bowel movements, an urgent need to have a bowel movement, constipation, and loss of bowel control. Our previous research suggests that hyperhomocysteinemia increased the occurrence of LARS. Folic acid, vitamin B6 and vitamin B12 are a safe, widely used way to treat hyperhomocysteinemia. The main questions this study aims to answer are: * Does taking Oral B-Complex Vitamin (B6, B9 and B12) lower the rate of LARS 6 months after surgery? * How does this treatment affect internal anal sphincter (IAS) function? Researchers will compare Oral B-Complex Vitamin (B6, B9 and B12) with a placebo (a look-alike tablet that contains no vitamins) to see if Oral B-Complex Vitamin (B6, B9 and B12) can help prevent LARS. Participants will: * Take B-Complex Vitamin (B6, B9 and B12) every day for 6 months * Visit the clinic twice ( 3 months and 6 months after surgery) for checkups and tests * Complete the LARS score questionnaire 6 months after surgery