Total Neoadjuvant Therapy and Organ Preservation Versus Surgery for Rectal Cancer.

Radiation therapy (RT) is administered at a dose of 2 Gy per day for a total dose of 50 Gy delivered to the pelvis. This is done throughout 5 to 6 weeks.

"Capecitabine: 825 mg/m² twice daily, prescribed 1-5 days per week, for 5 weeks during RT.~Or Bolus 5-FU regimen: 5-fluorouracil (5-FU) 400 mg/m2/day intravenously, administered on days 1-4 and 33-35. Calcium folinate (folinic acid) 20 mg/m2/day intravenously on days 1-4 and 33-35."

"XELOX: Oxaliplatin 130 mg/m² (day 1) + capecitabine 1000 mg/m² (days 1-14), every 3 weeks for 4 cycles.~Or FOLFOX: Oxaliplatin - 85 mg/m2 intravenously (2-hour infusion), drip for 1 day. Calcium folinate (folinic acid) - 400 mg/m2/d. intravenously (2-hour infusion), started on day 1. F(5-fluorouracil) - 400 mg/m2/d. intravenously (bolus), started on day 1. Repeat every 2 weeks for 6 times."

Transabdominal Resection: Abdominoperineal resection, low anterior resection, or coloanal anastomosis using total mesorectal excision.

Standard treatment protocols and follow-up procedures are implemented in clinical practice.

If indicated, adjuvant therapy will be administered as usual in clinical practice.