EP751 - Identifying Risk Factors for Positive Circumferential Resection Margin after Abdominoperineal Resection

Monday, May 12, 2025

10:31 AM – 10:36 AM PT

ePoster Presenter(s)

CF

Cyrus Feizpour, MD

Colorectal Surgery Fellow
Baylor University Medical Center
Dallas, TX, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Author(s)

IY

Irene S. Yu, MD

Fellow
Baylor Scott & White Health
Irving, Texas, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
AB

Adam Berenson, MD

Fellow
Baylor Scott & White Health
Dallas, TX, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
Katerina O.K Wells, MD MPH (she/her/hers)

Colorectal Surgeon
Baylor University Medical Center, Dallas
Dallas, TX, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no relevant relationships with ineligible companies.
RR

Roberto Rodriguez-Ruesga, MD

Attending
Baylor University Medical Center
Dallas, Texas, United States

Disclosure information not submitted.
WL

Warren Lichliter, MD

Surgeon
Baylor Scott & White Health
dallas, Texas, United States

Disclosure information not submitted.

Senior Author(s)

James W. Fleshman, Jr., MD

Surgeon
Baylor Scott & White Health
Dallas, Texas, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

All of the relevant financial relationships listed below have been mitigated.

Cyrus Feizpour, MD: This individual has no financial relationships with ineligible companies.

Irene S. Yu, MD: This individual has no financial relationships with ineligible companies.

Adam Berenson, MD: This individual has no financial relationships with ineligible companies.

Katerina O.K Wells, MD MPH: This individual has no relevant relationships with ineligible companies.

James W. Fleshman, MD, Jr.: This individual has no financial relationships with ineligible companies.

Image or Table (Do Not add text here):

Purpose/Background: Since the adoption of total mesorectal excision (TME) for rectal cancer, local recurrence rates have decreased significantly. Unfortunately, patients who require abdominoperineal resection (APR), as compared to a low anterior resection (LAR), more often have positive resection margins with worse oncologic outcomes. Surgical techniques, including patient positioning during the perineal dissection, can affect the ability to achieve a negative circumferential resection margin (CRM), impacting local recurrence rates; however, no definitive explanation has been found. Using single center institutional data, we aim to identify clinicopathologic risk factors for positive CRM in patients who underwent an APR.

Methods/Interventions: A retrospective review was performed to identify patients with rectal cancer who underwent APR from 2017 to 2021 at an urban tertiary center. Clinicopathologic characteristics were compared between patients who had positive CRM on the surgical specimen and those who did not. A multivariable logistic regression analysis of preoperative and intraoperative variables was performed, and Kaplan-Meier analysis was performed for survival analysis.

Results/Outcomes: We identified 42 patients who underwent APR including 9 (21%) with positive CRM (pCRM). Baseline characteristics between the groups were similar including age, body mass index, race, and rate of co-morbid conditions. The pCRM group had higher T-stage at presentation (T4, 63% v 7%, P=0.08) and more often required fecal diversion prior to definitive resection (22% v 3%, P=0.048). They had a significantly higher rate of positive CRM on post-neoadjuvant MRI (88% v 38%, P=0.02), but the rate not was significantly different on pre-neoadjuvant MRI (100% v 72%, P=0.09). Operative approach (Robotic, 11% v 51%, P=0.08) and patient positioning for the perineal dissection (Prone, 33% v 12%, P=0.15) were not significantly different between the pCRM and non-pCRM groups. On univariate logistic regression analysis both T-stage at presentation (OR 6.7, P=0.01) and positive CRM on post-neoadjuvant MRI (OR 11.2, P=0.03) were significant risk factors, but these did not remain significant on multivariable analysis. Overall and recurrence-free survival at 1-yr were both lower in the pCRM group (93% v 49%, P=0.009 and 92% v 49%, P=0.003, respectively).

Conclusion/Discussion: Our study found that a positive CRM on post-neoadjuvant MRI and locally advanced disease were associated with a positive CRM on the surgical resection specimen. However, surgical factors, such as the surgical approach and positioning, did not significantly impact CRM status.