EP104 - Locally Advanced Rectal Cancers that Straddle the Peritoneal Reflection: Upfront Resection versus Neoadjuvant Treatment Followed by Surgery

ePoster Presenter(s)

• 

  Benjamin Gallant, MD

  General Surgery Resident
  UMass Chan Medical School
  UMass Chan Medical School
  Worcester, MA, United States

  Disclosure information not submitted.

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Author(s)

• 

  Andrew Hu, MD

  General Surgery Resident
  UMass Chan Medical School
  University of Massachusetts T.H Chan Medical School
  Worcester, MA, United States

  All disclosed relationships have been reviewed and managed prior to the start of this activity. Any relevant relationships will be listed below. This individual has no financial relationships to disclose
• KL

  Klair Lubonja, MD

  General Surgery Resident
  UMass Memorial Health
  Shrewsbury, Massachusetts, United States

  Disclosure information not submitted.
• HH

  HyukJoo Hwang

  Medical Student
  University of Massachusetts Chan Medical School
  University of Massachusetts Chan Medical School
  Worcester, MA, United States

  Disclosure information not submitted.
• 

  Tess H. Aulet, MD (she/her/hers)

  Colorectal Surgeon
  UMass Memorial Medical Center
  UMass Memorial Medical Center
  Worcester, Massachusetts, United States

  All disclosed relationships have been reviewed and managed prior to the start of this activity. Any relevant relationships will be listed below. This individual has no relevant financial relationships.
• PS

  Paul R. Sturrock, MD

  Assistant Professor of Surgery
  UMassMemorial Medical Center
  Worcester, Massachusetts, United States

  Disclosure information not submitted.
• 

  Karim Alavi, MD, MPH

  Associate Professor of Surgery, Director, Colon and Rectal Surgery Fellowship
  UMass Chan Medical School
  southborough, Massachusetts, United States

  Disclosure information not submitted.
• 

  Justin Maykel, MD

  Chief, Division of Colorectal Surgery
  UMass Memorial Health
  UMass Chan Medical School
  Worcester, MA, United States

  All disclosed relationships have been reviewed and managed prior to the start of this activity. Any relevant relationships will be listed below. This individual has no relevant financial relationships.

Senior Author(s)

• TP

  Thomas Peponis, MD, FACS

  Colon and Rectal Surgeon, Assistant Professor of Surgery
  University of Massachusetts
  Worcester, Massachusetts, United States

  All disclosed relationships have been reviewed and managed prior to the start of this activity. Any relevant relationships will be listed below. This individual has no financial relationships to disclose

Purpose/Background: Locally advanced rectal cancers that straddle the peritoneal reflection often pose therapeutic challenges and lead to management dilemmas on multidisciplinary tumor board discussions. This study aimed to compare oncologic outcomes among patients who underwent an upfront proctectomy and those who received neoadjuvant treatment followed by either surgery or active surveillance.

Methods/Interventions: This is a retrospective study conducted at a high-volume, tertiary academic center. All patients diagnosed with stage II or III rectal adenocarcinoma from 09/2016 to 09/2025, whose baseline staging MRI revealed a tumor straddling the peritoneal reflection, were included in the study. Patients with Stage I or IV disease, inflammatory bowel disease, or hereditary polyposis syndromes were excluded from the analysis. The primary endpoint of the study was 2-year locoregional recurrence. Secondary endpoints included 2-year distant recurrence, disease-free survival, and overall survival.

Results/Outcomes: A total of 77 patients were included in the study, of whom 11 (14.3%) underwent upfront resection, while 66 (85.7%) received neoadjuvant treatment (total neoadjuvant therapy in 51.5%, chemoradiation alone in 43.9%, and chemotherapy alone in 4.5% of cases). Baseline demographics were similar between the groups. The distance of the primary tumor to the mesorectal fascia on baseline MRI was similar between the two groups (10.8 mm versus 8.0 mm, p = 0.375). Upfront resection was performed more often in tumors that were located farther from the anorectal junction (7.6 cm vs. 5.3 cm, p = 0.012). Eight patients achieved a clinical complete response following neoadjuvant treatment and elected to proceed with active surveillance instead of proctectomy. There was no difference in R0 resection rates or adequate (>12) lymph node harvest rate between the cohorts. Five (45.5%) upfront resection patients and 22 (36.7%) neoadjuvant patients required adjuvant therapy (p = 0.581). Median follow-up time was similar between cohorts, 31 months for the upfront resection and 29.9 months for the neoadjuvant cohort. There were no mortalities in either cohort. There was no difference in 2-year locoregional and distant recurrence rates or disease-free survival.

Conclusion/Discussion: This study demonstrated no significant difference in 2-year oncologic outcomes in patients with locally advanced rectal cancer that straddled the peritoneal reflection who were treated with upfront proctectomy versus neoadjuvant treatment followed by either surgery or active surveillance. Neoadjuvant treatment was given more frequently to patients with nodal disease and those whose peritoneal reflection was closer to the anorectal junction. Further research should evaluate oncologic outcomes beyond the initial two years post-treatment and focus on accurately identifying patients with locally advanced rectal cancer straddling the peritoneal reflection for whom neoadjuvant treatment can be safely omitted.

Table 1. Preoperative Radiographic and Endoscopic Findings
Table 2. Two-Year Oncologic Outcomes