Selective completion total mesorectal excision guided by intra-operative frozen pathology after local excision for low rectal cancer

Selective Total Mesorectal Excision Based on Intra-Operative Frozen Section From Local Excision in Rectal Cancer Undergoing Neoadjuvant Chemoradiotherapy: A Prospective, Single-arm, Phase II Superiority Trial

This trial tests whether using an immediate frozen-pathology result after local excision to decide if a full total mesorectal excision is needed can keep cancer controlled for adults with low rectal cancer who had a near-complete or small residual response to preoperative chemoradiotherapy.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 27 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: Sun Yat-sen University (other)
• Drugs / interventions: chemotherapy, radiation, immunotherapy
• Locations: 1 site (Guangzhou, Guanggong)
• Trial ID: NCT07337811 on ClinicalTrials.gov

What this trial studies

This is a prospective, single-arm phase II trial enrolling adults with primary rectal adenocarcinoma located ≤5 cm from the anal verge who show a near clinical complete response or a residual tumor <2 cm after neoadjuvant radiotherapy. All participants undergo local excision and the specimen is evaluated by intra-operative frozen section; if the frozen section shows ypT0-1 the procedure is concluded and the patient enters a watch-and-wait pathway, while ypT2-3 or positive margins prompt immediate completion total mesorectal excision (TME). The main goal is to test whether this selective organ-preserving strategy achieves favorable 2-year local control while reducing morbidity compared with routine upfront TME. The trial is conducted at Sun Yat-sen University Cancer Center in Guangzhou, China.

Who should consider this trial

Good fit: Adults aged 18–75 with pathologically confirmed rectal adenocarcinoma ≤5 cm from the anal verge who, at least 8 weeks after neoadjuvant radiotherapy, demonstrate a near-complete clinical response or a residual tumor smaller than 2 cm are ideal candidates.

Not a fit: Patients with larger or more invasive residual tumors on assessment, distant metastases, emergency surgical indications, or intra-operative frozen sections showing ypT2-3 or positive margins that require immediate TME are unlikely to gain organ-preserving benefit from this approach.

Why it matters

Potential benefit: If successful, this approach could preserve the rectum and sphincter function for many patients while lowering surgical morbidity by avoiding unnecessary radical surgery.

How similar studies have performed: Organ-preserving watch-and-wait strategies after clinical complete response have shown favorable outcomes in multiple studies, but using immediate intra-operative frozen-section to guide selective completion TME is a more recent strategy with limited prospective data.

Eligibility criteria

Inclusion Criteria:

1. Pathologically confirmed rectal adenocarcinoma.
2. Neoadjuvant therapy based on radiotherapy; post-radiotherapy evaluation ≥8 weeks later shows near clinical complete response (near-cCR) or partial response (PR) with residual tumor \<2 cm.
3. Tumor distance from the anal verge ≤5 cm.
4. Age 18-75 years.
5. No synchronous multiple primary cancers.
6. No contraindications to pre-operative radiotherapy or chemotherapy.
7. Adequate organ function (cardiac, hepatic, renal, hematologic).
8. Patient or legally authorized representative able to understand the study protocol, willing to participate, and provide written informed consent.

Exclusion Criteria:

1. Age \<18 or \>75 years.
2. Concurrent or previous malignancy within the past 5 years (except adequately treated basal-cell or squamous-cell skin carcinoma or carcinoma in situ of the cervix).
3. Emergency surgery required for bowel obstruction, perforation, or bleeding.
4. Prior colorectal surgery that may compromise intestinal reconstruction.
5. Need for en-bloc multivisceral resection.
6. ASA physical status IV or V.
7. Pregnant or lactating women.
8. a) Women of child-bearing potential with a positive serum pregnancy test at baseline or who have not undergone pregnancy testing; post-menopausal women must have been amenorrheic for ≥12 months.
9. b) Men or women of reproductive potential unwilling to use effective contraception throughout the study period.
10. Severe psychiatric illness precluding informed consent or compliance.
11. Severe COPD, interstitial lung disease, or ischemic heart disease precluding safe surgery.
12. Continuous systemic corticosteroid therapy within 1 month before enrolment.
13. Contraindications to laparoscopic surgery.
14. Patient or legally authorized representative unable to understand the study conditions and objectives.

Where this trial is running

Guangzhou, Guanggong

• Dept. of Colorectal Surgery, Sun Yat-sen University Cancer Center. Yuexiu District, Dongfeng East Road 651 — Guangzhou, Guanggong, China (RECRUITING)

Study contacts

• Principal investigator: Pei-Rong Ding — Sun Yat-sen University
• Study coordinator: Wei-Jian Mei

Conditions: Rectal Cancer Patients, Local Excision, Frozen Pathology, Chemoradiotherapy, Total Mesorectal Excision