Chemoradiotherapy After Surgery Versus Preoperative Chemoradiotherapy for Stage II/III Mid-low Rectal Cancer With or Without High-risk Factors

Inclusion criteria

• The patient is between 18 and 80 years old;
• Adenocarcinoma confirmed by pathology;
• Colonoscopy or imaging examination confirmed that the distance between the lower edge of the tumor and the anal margin is ≤10cm;
• ECOG score ≤2

(4) Imaging diagnostic analysis was cT1-3NxM0; (for Phase II/III) (5) CT examination of the chest and abdomen and pelvis showed no evidence of metastasis (6) Patients undergoing chemoradiotherapy and surgery

Exclusion criteria

• History of malignant tumors in the past;
• Diagnosis of simultaneous multiple primary colorectal cancer or other cancers;
• History of chemotherapy or radiotherapy prior to this trial
• Those with contraindications to laparoscopic surgery, such as severe cardiopulmonary insufficiency;
• Patients with intestinal obstruction, intestinal perforation, intestinal bleeding, etc., requiring emergency surgery;
• Pregnant or lactating women;
• Evidence of distant metastases prior to surgery
• T4b tumors were found to invade the uterus, vagina, bladder, seminal vesicles, prostate, bone, and pelvic plexus