Intraoperative Assessment of Distal Resection Margins Using Frozen Section in Mid and Low Rectal Cancer Surgery

NCT07398716 | Completed

• 1 other identifier: IOFS-DM
• Study Type: interventional
• Target: 99
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to improve the safety of distal surgical margins in patients with middle and low rectal cancer who receive neoadjuvant radiotherapy. Although magnetic resonance imaging and colonoscopic evaluation after neoadjuvant radiotherapy may suggest complete or near-complete tumor regression, residual tumor cells can still be present in the submucosal and muscular layers of the rectal wall. This may increase the risk of inadequate surgical margins and local recurrence. In this study, patients with middle and low rectal cancer who are scheduled for surgery after neoadjuvant radiotherapy will be randomized into two groups. In the frozen section group, intraoperative frozen section analysis of the resection specimen will be performed immediately after specimen removal to assess the distal resection margin, and the surgical procedure will be guided according to the frozen section results. In the control group, standard surgical resection will be performed without intraoperative frozen section evaluation. Pathological findings, distal margin status, operative time, tumor stage, and recurrence during follow-up will be compared between the two groups to evaluate the impact of intraoperative frozen section analysis on surgical margin safety and oncological outcomes.

Conditions

Rectal Cancer

Keywords

frozen section; Distal resection margin; Low rectal cancer; Mid rectal cancer

Outcome Measures

Primary Outcomes (1)

• Rate of Negative Distal Resection Margin (R0)

  Patients who obtained a negative result at the distal resection margin (defined as a tumor-free margin of at least 1 cm) according to intraoperative frozen section examination.

  During surgery

Secondary Outcomes (3)

• Need for Additional Resection or Conversion to Abdominoperineal Resection (APR)

  During surgery

• Local Recurrence Rate

  During postoperative follow-up (12- 24 months)

• Operative Time

  During surgery

Study Arms (2)

Intraoperative Frozen Section Group

EXPERIMENTAL

Patients undergo total mesorectal excision followed by intraoperative colonoscopy. After specimen removal, distal resection margins are assessed using intraoperative frozen section by an expert pathologist. Additional resection is performed if margins are positive or less than 1 cm. Abdominoperineal resection is performed if a safe margin cannot be achieved.

Procedure: Intraoperative Frozen Section Assessment

Control Group

ACTIVE COMPARATOR

Patients undergo total mesorectal excision followed by intraoperative colonoscopy. Resection is performed 2 cm distal to the tumor using a stapler, and anastomosis is completed without intraoperative frozen section assessment.

Procedure: Standard Surgery Without Frozen Section

Interventions

Intraoperative Frozen Section Assessment PROCEDURE

Intraoperative pathological evaluation of distal resection margins using frozen section to guide surgical decision-making.

Intraoperative Frozen Section Group

Standard Surgery Without Frozen Section PROCEDURE

Standard surgical resection without intraoperative frozen section assessment of distal margins.

Control Group

Eligibility Criteria

• Age: 18 Years - 90 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients diagnosed with mid or low rectal cancer (Stage I-III)
• Patients who have received short-course or long-course neoadjuvant radiotherapy
• Patients evaluated and approved for surgery by a multidisciplinary oncology board
• Patients scheduled for total mesorectal excision (TME)
• Age ≥ 18 years
• Patients who provide written informed consent

You may not qualify if:

• Stage IV rectal cancer
• Upper rectal tumors
• Patients undergoing emergency surgery
• Patients planned for local excision or palliative surgery
• Patients with distant metastasis
• Patients with a history of previous rectal surgery

Sponsors & Collaborators

• Bakirkoy Dr. Sadi Konuk Research and Training Hospital: lead

Study Sites (1)

Bakırköy Dr. Sadi Konuk Training and Research Hospital

Bakırköy, Istanbul, 34147, Turkey (Türkiye)

Location

Related Publications (2)

• Gomes RM, Bhandare M, Desouza A, Bal M, Saklani AP. Role of intraoperative frozen section for assessing distal resection margin after anterior resection. Int J Colorectal Dis. 2015 Aug;30(8):1081-9. doi: 10.1007/s00384-015-2244-4. Epub 2015 May 16.

  PMID: 25982468 RESULT

• Khoury W, Abboud W, Hershkovitz D, Duek SD. Frozen section examination may facilitate reconstructive surgery for mid and low rectal cancer. J Surg Oncol. 2014 Dec;110(8):997-1001. doi: 10.1002/jso.23758. Epub 2014 Sep 2.

  PMID: 25183166 RESULT

MeSH Terms

Conditions

Rectal Neoplasms

Interventions

Frozen Sections

Condition Hierarchy (Ancestors)

Colorectal Neoplasms; Intestinal Neoplasms; Gastrointestinal Neoplasms; Digestive System Neoplasms; Neoplasms by Site; Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Diseases; Rectal Diseases

Intervention Hierarchy (Ancestors)

Cryoultramicrotomy; Microtomy; Histocytological Preparation Techniques; Cytological Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Histological Techniques; Investigative Techniques

Study Officials

• Nurettin Sahin, MD

  Bakirkoy Dr. Sadi Konuk Research and Training Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: This is a prospective, randomized, two-arm, parallel-group interventional study comparing intraoperative frozen section assessment of distal resection margins versus standard surgery in mid and low rectal cancer.

Study Record Dates

• First Submitted: January 25, 2026
• First Posted: February 10, 2026
• Study Start: January 1, 2022
• Primary Completion: January 1, 2025
• Study Completion: January 1, 2026
• Last Updated: February 11, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)