EP106 - Quality of Mesorectal Excision After Total Neoadjuvant Therapy Versus Traditional Neoadjuvant Chemoradiotherapy: A Propensity-Matched Analysis

ePoster Presenter(s)

• 

  Melik Kagan Aktas, MD (he/him/his)

  Postdoctoral Clinical Research Fellow
  The Ohio State University Department of Surgery
  The Ohio State University
  Columbus, OH, United States

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

Author(s)

• 

  Matthew F. Kalady, MD

  Professor, Division Director,
  The Ohio State University Wexner Medical Center and James Cancer Center
  Ohio State University
  Columbus, Ohio, United States

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

  Alan E. Harzman, MD

  Professor
  The Ohio State University
  Columbus, Ohio, United States

  Disclosure information not submitted.
• AG

  Alessandra Gasior, DO

  Associate Professor
  The Ohio State University
  Columbus, Ohio, United States

  Disclosure information not submitted.
• 

  Lisa A. Cunningham, MD

  Assistant Professor
  The Ohio State University
  Columbus, Ohio, United States

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

  Emily Huang, MD, MEd

  Associate Professor
  The Ohio State University
  Ohio State University
  Columbus, OH, United States

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

  Amber L. Traugott, MD (she/her/hers)

  Associate Professor
  The Ohio State University
  The Ohio State University Wexner Medical Center
  Columbus, Ohio, United States

  Disclosure information not submitted.
• 

  Nikita Wadhwani, MD (she/her/hers)

  Colon and rectal surgery fellow
  The Ohio State University
  University of Alabama at Birmingham
  Columbus, OH, United States

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

  Sydney C. Beache, MD, MPHS (she/her/hers)

  Fellow
  The Ohio State University
  The Ohio State University
  Columbus, OH, United States

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

Senior Author(s)

• 

  Syed Husain, MB.,BS.

  Professor of Surgery-Clinical
  The Ohio State University
  Ohio State University
  Columbus, Ohio, United States

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

Purpose/Background: Total neoadjuvant therapy (TNT) has emerged as the main treatment for locally advanced rectal cancer. A recent survey reported resections following TNT to be technically more challenging due to fibrosis and loss of tissue planes associated with the extended interval after radiation therapy. We hypothesized that increased technical complexity will lead to higher rates of incomplete mesorectal excision in TNT cohort compared to the traditional neoadjuvant chemoradiotherapy (nCRT) cohort.

Methods/Interventions: Rectal cancer patients diagnosed between 2019 and 2024 and treated with TNT (Long course chemoradiation + consolidation chemotherapy) or nCRT were retrospectively analyzed using a prospectively maintained single-institution database. Patients were matched 1:1 using propensity scores (nearest neighbor with caliper 0.2) based on age, sex, American Society of Anesthesiologists (ASA) score, tumor location (low vs mid/upper rectum), BMI category (Obese ≥30 vs Non-Obese < 30), and operation type (LAR vs APR); unmatched patients were excluded to achieve balanced cohorts. Completeness of mesorectal excision was classified as Complete, Near-complete, or Incomplete, with Complete and Near-complete combined into one group for analysis. Covariate balance between matched groups was assessed using standardized mean difference (SMD) and visually displayed with a Love plot, with a threshold of 0.1 indicating adequate balance. Fisher's exact test was used to compare rates of incomplete mesorectal excision between TNT and nCRT groups.

Results/Outcomes: The propensity-matched cohort included 33 TNT and 33 nCRT patients. Baseline characteristics were well balanced between groups, with absolute SMDs remaining low (Figure 1). Detailed baseline characteristics of the matched groups are presented in Table 1. The median interval from completion of radiotherapy to surgery was significantly longer in the TNT group (182 days, range 70-238) compared with the nCRT group (67 days, range 29-157; p < 0.001). Estimated blood loss was comparable between groups (100 mL vs 100 mL, p = 0.938), while operative time was significantly longer in the TNT group (6.5 hours vs 3.6 hours, p < 0.001). Assessment of mesorectal excision showed that 78.8% of TNT patients achieved complete or near-complete excision compared with 84.8% of nCRT patients (OR = 0.67 (95% CI (0.15-2.80), p = 0.750).

Conclusion/Discussion: Although resections following TNT have been reported as technically challenging and were associated with significantly longer operative times in our cohort, mesorectal excision completeness remained comparable to nCRT, reinforcing the oncologic integrity of surgery following TNT. Studies with larger patient cohorts are needed to validate these findings.



Description:

This study hypothesized that increased technical complexity would lead to higher rates of incomplete mesorectal excision in patients undergoing total neoadjuvant therapy (TNT) compared with traditional neoadjuvant chemoradiotherapy (nCRT). Although resections after TNT were reported as technically more challenging and associated with significantly longer operative times in propensity-matched analysis, mesorectal excision completeness was comparable between groups.

Figure 1: Covariate balance between Total Neoadjuvant Therapy (TNT) and Traditional Neoadjuvant Chemoradiotherapy (nCRT) groups before and after propensity-score matching
Table 1: Baseline Characteristics and Completeness of Mesorectal Excision in the Propensity-Matched Cohorts of Total Neoadjuvant Therapy (TNT) and Traditional Neoadjuvant Chemoradiotherapy (nCRT)