Conformal Sphincter-Preservation Operation Versus InterSphincteric Resection on Anal Function in Low Rectal Cancer

A Multicenter, Prospective, Randomized Controlled Clinical Trial of the Effect of Conformal Sphincter-preservation Operation Versus Intersphincteric Resection on Postoperative Anal Function in Patients With Low Rectal Cancer

In this clinical trial, the investigators compared anal function, genitourinary function, quality of life, perioperative safety, and oncological prognosis after CSPO for patients with low rectal cancer, using ISR as a control, to provide high-level evidence-based medical evidence for the choice of anorectal preservation surgical approaches for patients with low rectal cancer.

The CSPO surgical approach is a series of targeted improvements designed primarily on the basis of analyzing the causes of poor postoperative function of the ISR, while building on research on the ultrastructure of the pelvic floor anal canal. For these reasons, the investigators designed the present study to compare anal function, quality of life, perioperative safety, and oncologic prognosis after CSPO for patients with low rectal cancer, using ISR surgery as a control, and to provide high-level evidence-based medical evidence for the choice of anorectal preservation surgical modalities for patients with low rectal cancer.

Inclusion Criteria:

1. Age: 18-75 years;
2. Pathologically confirmed: moderately & well-differentiated rectal cancer;
3. Low rectal cancer: lower edge of tumor ≦5cm from anal verge or ≦2cm from dentate line;
4. Tumor diameter: ≤3cm or <1/3 bowel circumference;
5. Tumor infiltration depth: cT1-2, Bordeaux/Rullier classification: type II-III;
6. Locally progressive rectal cancer (cT1-4N0-2M0): significant tumor downstaging and downgrading after preoperative neoadjuvant therapy, meeting the above criteria;
7. ASA score: I-III and ECOG score: 0-1;
8. Undergo elective TME for colorectal or colorectal-anal canal anastomosis;
9. Normal preoperative anal function: Wexner score <10, LARS score <20;
10. Agree to participate in the clinical trial and sign an informed consent form.

Exclusion Criteria:

1. Combination of synchronous or metachronous (within 5 years) malignant tumors;
2. Combined distant metastasis of the tumor;
3. Combined intestinal obstruction, intestinal perforation, or intestinal bleeding requiring emergency surgery;
4. Combined psychiatric disorders that do not allow them to understand and participate in the study;
5. Combined systemic diseases that cannot tolerate surgery;
6. Women who are pregnant or breastfeeding;
7. Other reasons, judged by the investigator, for not being suitable for participation in this clinical trial.