The goal of this clinical trial is to learn whether the extra-peritoneal tunneling (EPT) drain fixation method works better and more safely than the conventional drain insertion method after rectal cancer surgery.

It will also learn about the safety and possible complications of the EPT technique.

The main questions it aims to answer are:

Does the EPT drain fixation method increase the success rate of conservative management (drain maintenance and/or antibiotics) when an anastomotic leak occurs?

Does the EPT method reduce the rate of drain displacement compared with the conventional method?

Are there any safety concerns or complications associated with the EPT method?

Researchers will compare EPT drain fixation to the conventional drain method to see which approach provides better outcomes after anterior or low anterior resection for rectal cancer.

Participants will:

Undergo anterior or low anterior resection for rectal cancer as part of their standard surgical treatment.

Be randomly assigned to either the EPT drain fixation group or the conventional drain group.

Receive the same postoperative care as usual, including follow-up imaging to monitor drain position and recovery.

Be observed for postoperative outcomes such as anastomotic leakage, drain position, and related complications until recovery.

This study will help determine whether securing the drain through an extra-peritoneal tunnel can prevent drain movement, improve early management of leakage, and enhance patient recovery after rectal surgery.

resection for rectal cancer. Although prophylactic pelvic drainage has been widely used to detect early leakage and to prevent pelvic sepsis, recent randomized trials and meta-analyses have reported that routine drain placement provides no significant benefit in reducing postoperative morbidity. One possible reason is drain displacement, which occurs in up to 30-40% of cases, resulting in the drain being positioned far from the anastomotic site and losing its intended function.

The extra-peritoneal tunneling (EPT) drain fixation method is a new surgical technique designed to prevent drain displacement by creating an extraperitoneal tunnel that anchors the drain securely near the anastomosis. This technique is performed using the Drain-TG™ (DTG) device developed by JSR Medical (Daegu, Korea). Preliminary retrospective data have shown that the EPT technique dramatically reduces drain displacement (2.8% vs. 40% with conventional insertion, p < 0.001) and that, in patients who developed AL, the success rate of conservative management (drain maintenance and antibiotics only) exceeded 80%, compared with 43% in the conventional group.

The ExPeTuD trial is a prospective, multi-center, randomized controlled trial that aims to establish strong evidence for the efficacy and safety of the EPT drain fixation method. Patients undergoing anterior or low anterior resection with a predicted anastomosis ≤ 10 cm from the anal verge will be enrolled from approximately 20 tertiary hospitals across Korea. Participants will be randomized 1:1 to either the EPT group or the conventional drain group, stratified by sex, tumor level (above vs. below the peritoneal reflection), and preoperative chemoradiation status.

The primary outcome is the success rate of conservative management (drain maintenance and/or antibiotics) for AL according to drain insertion method. Secondary outcomes include:

Rate and timing of drain displacement (defined as > 3 cm separation from the anastomotic site on X-ray),

Drain-related complications (infection, pain, bleeding, or organ injury),

Time to diagnosis of AL and time to re-intervention,

Postoperative recovery outcomes such as ileus, hospital stay, and overall morbidity (Clavien-Dindo classification).

Radiologic monitoring (abdominal X-rays on postoperative days 2, 4, and 6) will be performed to assess drain position, and additional imaging will be conducted if AL is suspected. Standard postoperative care, including enhanced recovery after surgery (ERAS) protocols, will be applied equally to both groups.

A total of 596 participants (298 per arm) will be recruited, which accounts for an expected 6% AL rate after low anterior resection and ensures sufficient power for superiority testing. Interim analysis will be conducted once ≥ 9 AL events occur in each group to assess safety and trial feasibility.

If the EPT drain fixation method proves effective in maintaining drain position and improving conservative management success rates, it could reduce the need for reoperation, shorten hospital stay, and improve patient outcomes after rectal cancer surgery. This trial aims to provide robust clinical evidence supporting the adoption of the EPT technique as a standard method for pelvic drainage following proctectomy.

Inclusion Criteria:

• Patients scheduled to undergo rectal resection (anterior resection or low anterior resection) with planned intraoperative drain placement.
• Expected anastomotic level ≤10 cm from the anal verge based on preoperative imaging or endoscopic evaluation.

Exclusion Criteria:

• Patients scheduled to undergo additional colonic resection (e.g., right hemicolectomy, transverse colectomy).
• Patients in whom no intraoperative drain placement is planned.
• Patients scheduled for permanent or end stoma formation (e.g., abdominoperineal resection or Hartmann's procedure).
• Patients with prior pelvic surgery (e.g., hysterectomy, prostatectomy, pelvic lymph node dissection) that may cause pelvic adhesions or anatomic distortion.
• Patients with ASA physical status IV or severe systemic disease expected to require postoperative intensive care unit (ICU) admission.
• Patients who decline to provide informed consent for study participation

We have not yet determined whether individual participant data (IPD) will be shared. If sharing is approved, only de-identified IPD related to primary and key secondary outcomes will be made available.

All enrolled patients will undergo the same standard surgical and postoperative management, except for the method of drain placement. No masking will be applied because the surgical procedure is visibly different and performed intraoperatively. The trial will follow participants through postoperative recovery until drain removal and hospital discharge, with standardized imaging to assess drain position and detect anastomotic leakage. This design allows for direct comparison of efficacy and safety outcomes between the two techniques in real-world surgical settings.