EP364 - On the Edge: Pathology Quality in Robotic and Laparoscopic Proctectomy, a Propensity Score–Matched Study

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.

Author(s)

• KW

  Kayla R. Widdowson, MD

  Resident Physician
  UMass Chan Medical School
  Worcester, Massachusetts, United States

  Disclosure information not submitted.
• 

  Andrew Hu, MD

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

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

  Robert Plummer, MD

  Resident
  UMass
  Morristown, New Jersey, 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 of the relevant financial relationships listed below have been mitigated.
  This individual has no relevant relationships with ineligible companies.
• PS

  Paul R. Sturrock, MD

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

  Disclosure information not submitted.
• TP

  Thomas Peponis, MD, FACS

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

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

  Justin Maykel, MD

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

  Disclosure information not submitted.
• KL

  Kate L. Lapane, PhD

  Associate Dean
  University of Massachusetts Chan Medical School
  Worcester, Massachusetts, United States

  Disclosure information not submitted.

Senior Author(s)

• 

  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.

Purpose/Background: Minimally invasive approaches for rectal cancer resection offer lower postoperative morbidity compared with open surgery. Achieving negative resection margins and adequate lymph node harvest remains essential for long-term survival following proctectomy. Robotic surgery has seen increasing adoption over time, though its benefits over conventional laparoscopy remain unclear in patients with rectal cancer. We compared differences in the quality of composite pathology specimens and long-term survival between robotic and laparoscopic proctectomy in a national sample of patients with rectal cancer.

Methods/Interventions: We conducted a retrospective cohort study using data from the National Cancer Database (NCDB) from 2010 to 2021. The study included adults with stage I-III rectal adenocarcinoma who underwent elective minimally invasive proctectomy at institutions offering both laparoscopic and robotic surgery. Patients who underwent open surgery or had missing data were excluded. The primary study outcome was an optimal composite pathologic specimen, defined as negative resection margins (R0) and the harvest of ≥12 lymph nodes. Propensity score matching was used to balance baseline covariates between the two primary comparison groups. A Poisson regression model estimated the likelihood of obtaining an optimal composite pathology specimen. Between group differences in 5-year survival rates were examined using Kaplan-Meier survival curves.

Results/Outcomes: After propensity score matching, 18,437 subjects were included in each study group. Our two primary comparison groups were well balanced across patient demographics, tumor staging, and receipt of systemic therapy. The mean age of the study sample was 58.6 years, and 61% were men. Most patients had stage 3 disease (40.7% for robotic, 42.5% for laparoscopic) and underwent neoadjuvant treatment (37.6% for robotic, 40.6% for laparoscopic). Robotic proctectomy was significantly more likely to yield an optimal composite pathology specimen (relative risk 1.04, 95% CI: 1.02-1.05). Robotic proctectomy had a lower rate of positive margins (4.5%) compared to laparoscopy (5.0%, p = 0.04). Additionally, robotic proctectomy was associated with a lower rate of insufficient lymph node yield (19.3%), defined as < 12 lymph nodes, compared to laparoscopic patients (21.9%, p < 0.001). There were no significant differences in 5-year survival rates between the robotic (82.2%) and laparoscopic (81.9%) study groups.

Conclusion/Discussion: Robotic proctectomy was more likely than laparoscopy to yield an optimal composite pathology specimen, while both approaches achieved similar long-term survival. These results indicate that robotic proctectomy is associated with oncologic outcomes comparable to those of laparoscopy. It remains uncertain whether these differences are attributable to technical factors or other influences. Future studies should aim to identify which patients derive the greatest benefit from a robotic approach, thereby guiding individualized treatment decisions.

Table 1. Likelihood of Achieving an Optimal Composite Pathology Specimen Using a Robotic Surgery Approach
Figure 1. Kaplan-Meier Five-Year Overall Survival Curves