Comparative Study on the Short- and Long-term Efficacy of Q-ISR, Traditional Sub-ISR, and t-ISR

This comparative study evaluates the short- and long-term outcomes of Quadrant-based Intersphincteric Resection (Q-ISR) versus traditional subtotal ISR (Sub-ISR) and conventional/total ISR (t-ISR) in patients with ultra-low rectal cancer undergoing sphincter-preserving surgery, with short-term endpoints focusing on perioperative safety (operative time, blood loss, length of stay, and postoperative complications such as Clavien-Dindo grade ≥II, anastomotic leakage/stricture, and stoma reversal) and long-term endpoints assessing anorectal function recovery (LARS and Wexner scores after stoma closure) and oncologic efficacy (R0 resection, recurrence patterns, and survival outcomes), aiming to determine whether a quadrant-tailored resection strategy can better balance tumor control with anal function preservation.

Study Overview

• Status: Recruiting
• Conditions: Colorectal Cancer
• Intervention / Treatment: Procedure: Quadrant-based Intersphincteric Resection

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Dawei Li; Phone Number: +86-021-64175590; Email: li_dawei@fudan.edu.cn

Study Locations

• China
  • Shanghai, China
    • Recruiting
    • Fudan University Shanghai Cancer Center
    • Contact: Dawei Li; Phone Number: +86-021-64175590; Email: li_dawei@fudan.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• (1) Rectal cancer diagnosed by digital rectal examination, colonoscopy, and combined biopsy pathology. (2) The distance from the lower edge of the tumor to the dentate line is 1.5-2.0 cm. (3) Good anal function before surgery. (4) The tumor does not infiltrate the intersphincteric space. (5) The tumor length is less than 3 cm, and the proportion of the tumor occupying the intestinal lumen is less than 1/3 of the circumference. (6) American Society of Anesthesiologists (ASA) score is ≤3.

Exclusion Criteria:

• (1) Presence of distant metastasis. (2) Undifferentiated carcinoma or mucinous adenocarcinoma.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Q-ISR; Based on preoperative precise assessment and rectal endoscopic localization, selective resection of the internal sphincter is performed "by quadrant and quantificationally" according to the extent of lesion involvement, while striving to preserve the uninvolved quadrants and the external sphincter-levator ani complex. This aims to ensure R0 resection margins and oncological safety, while reducing the risk of low anterior resection syndrome (LARS) and accelerating the recovery of bowel control function.

Procedure: Quadrant-based Intersphincteric Resection; Q-ISR (Quadrant-based ISR): Based on preoperative precise assessment and rectal endoscopic localization, selective resection of the internal sphincter is performed "by quadrant and quantificationally" according to the extent of lesion involvement, while striving to preserve the uninvolved quadrants and the external sphincter-levator ani complex. This aims to ensure R0 resection margins and oncological safety, while reducing the risk of low anterior resection syndrome (LARS) and accelerating the recovery of bowel control function.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Wexner score	3years
LARS scores	3years
disease-free survival	5years

Collaborators and Investigators

• Sponsor: Fudan University

Study record dates

Study Major Dates

• Study Start (Actual): January 7, 2026
• Primary Completion (Estimated): January 7, 2029
• Study Completion (Estimated): December 30, 2029

Study Registration Dates

• First Submitted: January 19, 2026
• First Submitted That Met QC Criteria: January 19, 2026
• First Posted (Actual): January 27, 2026

Study Record Updates

• Last Update Posted (Actual): January 27, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colonic Diseases; Colorectal Neoplasms
• Other Study ID Numbers: Q-ISR

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No