Intraoperative Assessment of Distal Resection Margins Using Frozen Section in Mid and Low Rectal Cancer Surgery
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Enrollment
- 99
- Locations
- 1
- Primary Endpoint
- Rate of Negative Distal Resection Margin (R0)
Study Overview
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.
Detailed Description
Middle and low rectal cancers often show a good response to neoadjuvant radiotherapy or chemoradiotherapy. However, despite apparent tumor regression or disappearance on preoperative magnetic resonance imaging and intraoperative colonoscopic evaluation, residual tumor cells may persist within the submucosal or muscular layers of the rectal wall. This residual disease may not be detected by mucosal inspection alone and may lead to inadequate distal resection margins, increasing the risk of local recurrence or the need for more radical surgery.
The primary aim of this study is to evaluate whether intraoperative frozen section analysis of the distal resection margin improves surgical margin safety in patients with middle and low rectal cancer undergoing surgery after neoadjuvant radiotherapy.
This is a prospective, randomized clinical study conducted at Bakırköy Dr. Sadi Konuk Training and Research Hospital. Patients diagnosed with middle or low rectal adenocarcinoma (stage I-III) who have undergone short-course or long-course neoadjuvant radiotherapy and have been discussed in a multidisciplinary oncology council will be included. Following restaging with pelvic magnetic resonance imaging, patients deemed suitable for surgical treatment will be enrolled.
Eligible patients will be randomized into two groups using a sealed-envelope method. All patients will undergo total mesorectal excision according to standard oncologic principles. Immediately before rectal transection, intraoperative colonoscopy will be performed in all patients, and rectal transection will be planned at 2 cm distal to the tumor site identified during colonoscopy using an endoscopic linear stapler.
In the frozen section group, after specimen removal, the resection specimen will be immediately evaluated by an experienced gastrointestinal pathologist using intraoperative frozen section analysis. A distal margin of at least 1 cm will be considered oncologically safe. If the distal margin is found to be positive or closer than 1 cm, further rectal resection will be performed until a safe margin is achieved. If a safe distal margin cannot be obtained despite additional resection, abdominoperineal resection will be performed.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to 90 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •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
Exclusion Criteria
- •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
Arms & Interventions
Intraoperative Frozen Section Group
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.
Intervention: Intraoperative Frozen Section Assessment (Procedure)
Control Group
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.
Intervention: Standard Surgery Without Frozen Section (Procedure)
Outcomes
Primary Outcomes
Rate of Negative Distal Resection Margin (R0)
Time Frame: During surgery
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.
Secondary Outcomes
- 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)
Investigators
Nurettin Şahin
Principal Investigator
Bakirkoy Dr. Sadi Konuk Research and Training Hospital