eP221 - Anterior Peritoneal Reflection as a Prognostic Marker in Rectal Cancer: Analysis of Outcomes

ePoster Presenter(s)

• 

  Fernando Lambreton, 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)

• 

  Teena Nerwal, MD

  Colorectal fellow
  Baylor
  Baylor
  Dallas, TX, United States

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

  Brandon Smith, MD

  Fellow - Colon and Rectal Surgery
  Baylor University Medical Center
  Springfield, MA, United States

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

  Christian Sommerhalder, MD

  Colorectal Surgeron
  Baylor University Medical Center
  Dalals, Texas, United States

  Disclosure information not submitted.
• GO

  Gerald Ogola, PhD

  Biostatistician
  Baylor University Medical Center
  Dallas, Texas, United States

  Disclosure information not submitted.
• AW

  Anthony Waddimba, PhD

  Research Investigator
  Baylor University Medical Center
  Dallas, Texas, United States

  Disclosure information not submitted.
• MP

  Michael Pendola, MD

  Colorectal Surgeron
  Baylor University Medical Center
  Dallas, Texas, United States

  Disclosure information not submitted.
• WL

  Warren Lichliter, MD FACS FACRS

  Program Director C&R Surgery
  Baylor University Medical Center Dallas Texas
  Da, Texas, United States

  Disclosure information not submitted.
• EF

  Edward Franko, MD

  C
  Baylor University Medical Center
  Dallas, Texas, United States

  Disclosure information not submitted.
• SS

  Sarah Stringfield, MD (she/her/hers)

  Colorectal Surgeon
  Baylor University Medical Center, Dallas, TX

  Disclosure information not submitted.
• 

  Alessandro Fichera, MD (he/him/his)

  Division Chief Colorectal Surgery
  Baylor University Medical Center
  Texas A&M
  Dallas, TX, United States

  All relevant financial disclosures have been managed and will be listed below.
  This individual has no financial relationships with ineligible companies.
• RR

  Roberto Rodriguez-Ruesga, MD

  Colorectal Surgeron
  Baylor University Medical Center
  Dallas, Texas, United States

  Disclosure information not submitted.
• 

  Katerina O.K. Wells, MD MPH

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

  Disclosure information not submitted.

Senior Author(s)

• 

  James W. Fleshman, MD, FACS, FASCRS

  Department Chair of Surgery
  Baylor University Medical Center
  Texas A&M College of Medicine
  Plano, TX, United States

  Disclosure information not submitted.

Purpose/Background: Tumor distance from the anal verge is used to classify rectal tumors by convention and carries significant prognostic import. However, this measure is highly variable when applied to different pelvic phenotypes. As pelvic MRI becomes a more accurate tool for rectal cancer management, we propose tumor relationship to the peritoneal reflection as another classification tool to characterize and prognosticate tumor behavior. We hypothesize that Relationship to anterior peritoneal reflection (AR) is a key landmark that determines the tumor’s biology.Methods/Interventions: A prospectively maintained, institutional database of patients treated for rectal cancer at our institution from 2018 to 2021 was queried under an approved umbrella protocol through the institutional IRB. To evaluate characteristics of tumors relative to their position on the AR, surgical, radiographic, pathologic and oncologic variables were included in our analysis. Uni- and multivariate analysis was performed.Results/Outcomes: 169 patients were included. Tumors above the AR had a significantly higher median number of lymph nodes harvested 20.5, compared to those below and straddling the AR (13, 15 respectively, p=0.004). There was no difference in rate of positive nodes. Threatened or positive circumferential resection margins (CRM) were reported in 43% of tumors above the AR, compared to 54% below AR, and 63% straddling AR (p=0.2). A higher rate of positive CRM was seen after abdominoperineal resection (APR) compared to low anterior resection (LAR) (59% vs 26%, p=0.003). Neoadjuvant treatment was given in 45%, 83%, and 91% of tumors above, below, and straddling the AR, respectively. Local recurrence rates were similar for tumors above, below, or straddling the APR. (14%, 13%, 8%, respectively). Laparoscopic surgery was more commonly performed in tumors above and straddling the AR than for those below the AR (50%, 41%, 26%, p=0.02) A trend towards higher mortality was seen in patients who underwent open surgery than laparoscopic or robotic approach (17%, 7%, 3% respectively. P=0.08). Higher mortality was seen in tumors below or straddling AR than those above AR (8%, 8%, 0%, respectively).Conclusion/

Discussion: Tumors above the AR have higher number of lymph nodes harvested, less positive CRM, and less mortality. These tumors are also more amenable to a minimally invasive approach to resection compared to tumors straddling or below the AR. These findings indicate that tumors above the AR may demonstrate a more weighted risk-to-benefit ratio than previously understood when considering indications for neoadjvant therapy.Table 1Comparison of outcomes. Lymph node harvest reported as median and interquartile ranges.