Selective Total Mesorectal Excision Based on Intra-Operative Frozen Section From Local Excision in Rectal Cancer Undergoing Neoadjuvant Chemoradiotherapy
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
Sun Yat-sen University
27 participants
Aug 1, 2025
INTERVENTIONAL
Conditions
Summary
This study is a prospective, single-arm, phase II superiority trial to determine whether a selective organ-preserving strategy based on immediate intra-operative frozen-section results can achieve favorable 2-year local control while lowering morbidity in patients with low rectal cancer (tumor ≤5 cm from the anus) who have a near clinical complete response (near-cCR) or partial response (residual tumor \<2 cm) after radiation therapy. Population: Adults with primary rectal adenocarcinoma located ≤5 cm from the anal verge who, after neoadjuvant radiotherapy, are judged to have near-cCR or partial response (residual tumor \<2 cm). Intervention: All participants undergo local excision under general anesthesia. The specimen is sent for intra-operative frozen section. ypT0-1 on frozen section → procedure concluded; patient enters watch-and-wait. ypT2-3 or R1 on frozen section → immediate completion total mesorectal excision (TME). Frozen-section ypT1-2 but final paraffin section up-staged to ypT2-3 or R1 → elective TME within 8 weeks. Primary Endpoint: a composite outcome of 2-year local recurrence rate, surgical complications (≤30 days), and long-term functional impairment (anorectal, urogenital, and quality-of-life scales). Secondary Endpoints: Agreement between intra-operative frozen-section pathology and final paraffin-section pathology, 3-year disease-free survival (DFS), 3-year overall survival (OS), surgery-sparing rate, post-operative recovery metrics, Quality-of-life scores. Estimated Enrollment: 27 participants.
Eligibility
Inclusion Criteria8
- Pathologically confirmed rectal adenocarcinoma.
- 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.
- Tumor distance from the anal verge ≤5 cm.
- Age 18-75 years.
- No synchronous multiple primary cancers.
- No contraindications to pre-operative radiotherapy or chemotherapy.
- Adequate organ function (cardiac, hepatic, renal, hematologic).
- Patient or legally authorized representative able to understand the study protocol, willing to participate, and provide written informed consent.
Exclusion Criteria14
- Age \<18 or \>75 years.
- 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).
- Emergency surgery required for bowel obstruction, perforation, or bleeding.
- Prior colorectal surgery that may compromise intestinal reconstruction.
- Need for en-bloc multivisceral resection.
- ASA physical status IV or V.
- Pregnant or lactating women.
- 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.
- b) Men or women of reproductive potential unwilling to use effective contraception throughout the study period.
- Severe psychiatric illness precluding informed consent or compliance.
- Severe COPD, interstitial lung disease, or ischemic heart disease precluding safe surgery.
- Continuous systemic corticosteroid therapy within 1 month before enrolment.
- Contraindications to laparoscopic surgery.
- Patient or legally authorized representative unable to understand the study conditions and objectives.
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Interventions
All participants undergo trans-anal full-thickness local excision under general anesthesia. The specimen is sent for intra-operative frozen-section pathology. ypT0-1 on frozen section → procedure concluded; patient enters watch-and-wait. ypT2-3 or R1 on frozen section → immediate completion total mesorectal excision (TME). Frozen-section ypT1-2 but final paraffin section up-staged to ypT2-3 or R1 → elective TME within 8 weeks.
Locations(1)
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NCT07337811