This study aims to systematically evaluate the safety and efficacy of different early urinary catheter removal strategies following radical resection of mid-low rectal cancer. Current clinical practice faces controversy regarding the optimal timing of catheter removal (24 hours vs. 48 hours) and lacks precise preventive measures for patients at high risk of postoperative acute urinary retention (AUR). To address these issues, this study is designed as a three-arm randomized controlled trial, directly comparing three management protocols: catheter removal at 24 hours postoperatively, catheter removal at 48 hours postoperatively, and an individualized strategy guided by a predictive model (i.e., preventive administration of tamsulosin to high-risk AUR patients prior to catheter removal). The primary endpoint is the rate of recatheterization within 7 days after the initial removal, with secondary endpoints comprehensively assessing urinary tract infections, voiding function, and postoperative complications. The ultimate goal is to provide high-quality evidence-based medical evidence to establish a precise and standardized clinical pathway for individualized postoperative catheter management.

Inclusion Criteria:

1. Patients with a preoperative pathological confirmation of rectal malignant tumor.
2. Preoperative colorectal CT or rectal MRI confirming that the lower edge of the tumor is located in the rectum within 10 cm from the anal verge (including rectal and anal canal lesions).
3. Patients scheduled to undergo laparoscopic or robot-assisted radical total mesorectal excision (TME).

Exclusion Criteria:

1. History of previous abdominal surgery involving the rectum/sigmoid colon/left colon, bladder resection or partial resection, prostate surgery (in males), or hysterectomy (in females).
2. History of urethral trauma, intracranial surgery, spinal surgery, cerebral infarction with limb dysfunction, or Parkinson's disease.
3. Inability to void urethrally preoperatively due to any reason (e.g., ureteral puncture, ureterostomy).
4. Previously diagnosed overactive bladder syndrome, prior AUR or voiding dysfunction, or diabetic cystopathy.
5. Preoperative assessment indicating potential need for combined resection of other pelvic organs during surgery, including the bladder, prostate, uterus and cervix, or vagina (excluding simple adnexectomy in females).
6. Preoperative assessment indicating potential need for lateral pelvic lymph node dissection.
7. Preoperative renal insufficiency (serum creatinine level >133 μmol/L).
8. Patients undergoing emergency surgery.
9. Male patients with preoperative benign prostatic hyperplasia requiring medication.
10. Presence of indwelling ureteral stents, ureteral stenosis, or bilateral hydronephrosis.

After we complete our study

Researchers may provide legitimate justification and supporting documentation.