EP212 - Disparities in the Treatment and Outcomes of Microsatellite Unstable Rectal Cancer: a Retrospective Study from the National Cancer Database

ePoster Presenter(s)

• 

  Jingyuan Zhang, MD (she/her/hers)

  Resident
  Cleveland Clinic Florida
  Cleveland Clinic Florida
  Weston, FL, United States

  Disclosure information not submitted.

Author(s)

• 

  Sameh H. Emile, MBBCh, MSc, MD, FACS

  Project Scientist
  Cleveland Clinic Florida
  Cleveland Clinic Florida
  Weston, FL, United States

  Disclosure information not submitted.
• 

  Nir Horesh, MD

  Resident Physician
  Cleveland Clinic Florida
  Tel Aviv University
  Weston, FL, United States

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

  Seyma N. Avci, MD

  General Surgery Resident
  Cleveland Clinic Florida
  Cleveland Clinic Florida
  Sunrise, FL, United States

  Disclosure information not submitted.
• 

  Ilana Grosman Setton, MD

  General Surgical Resident
  Cleveland Clinic Florida
  Cleveland Clinic Florida
  Weston, FL, United States

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

  Roberto Valera, MD

  General Surgery Resident
  Cleveland Clinic Florida
  Weston, Florida, United States

  Disclosure information not submitted.
• 

  Marylise Boutros, MD, FRCSC, FACS, FACRS (she/her/hers)

  Colorectal Surgeon
  Cleveland Clinic Florida
  McGill University
  Weston, Florida, United States

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

  Giovanna Dasilva, MD

  Staff Colorectal Surgeon
  Cleveland Clinic Florida
  Cleveland Clinic Florida
  Weston, Florida, United States

  Disclosure information not submitted.

Senior Author(s)

• 

  Steven D. Wexner, MD, PhD (Hon)

  Surgeon
  Cleveland Clinic Florida
  Cleveland Clinic Lerner College of Medicine at Case Western Reserve University
  Weston, Florida, United States

  Disclosure information not submitted.

Purpose/Background: Microsatellite instability (MSI) status is an important prognostic factor that affects treatment and outcomes in colorectal cancer, with novel therapeutic options with the introduction of immune checkpoint inhibitors in recent years. However, there is little known about the effect of socio-economic disparities in treatment received and patients' outcomes. This study aimed to investigate disparities in treatment and their effect on patients' short- and long-term outcomes in rectal cancer patients with MSI positive tumors.

Methods/Interventions: We conducted a retrospective cohort analysis of patients with locally advanced (stage II-III) MSI positive rectal adenocarcinoma who underwent proctectomy between 2004 and 2021 included in the National Cancer Database (NCDB). Patients were characterized by their insurance types, area of residence, and treatment facility types. Treatment modalities and short-term outcomes were analyzed. 5-year overall survival (OS) was assessed using Kaplan Meier survival analysis.

Results/Outcomes: The study included 2,993 patients (62.4% male, 37.6% female), with 26.3% aged under 50 years. 50.4% of the patients were privately insured and 45.1% had governmental insurance. 81.2% resided in metropolitan areas. 41.8% received treatment at academic facilities, 38.9% at community facilities, and 19.4% at integrated network cancer programs. 80.7% of patients had neoadjuvant radiation. Low anterior resection (60.9%) was the most performed surgery, followed by abdominoperineal resection (22.2%). Most patients received minimally invasive surgeries (MIS) (30.9% laparoscopic, 30.7% robotic). Compared to patients with governmental insurance, privately insured patients were more likely treated with neoadjuvant radiation (83.1% vs. 78%, p=0.002), sphincter sparing surgery (75.4% vs. 67.2%, p< 0.001), MIS surgery (64.0% vs. 59.7%, p=0.035), had lower rates of 30 day mortality (0.4% vs. 1.3%, p=0.025) and 90 day mortality (0.8% vs. 2.7%, p=0.001), and higher 5 year OS (81.9% (79.4-84%) vs. 64.7% (61.5-67.8%), p< 0.001). Compared to non-metropolitan residents, metropolitan residents were more likely to undergo MIS surgery (62.8% vs. 56.2%, p=0.011) and had higher 5-year OS (75% (72.8-77%) vs. 67.5% (62.4-72%), p=0.007). The treatment facility type did not significantly affect treatment, outcomes, or 5-year OS. The highest rate of MIS was in integrated network cancer programs (67.8%) followed by community centers (62.8%) and academic centers (58.2%).

Conclusion/Discussion: Insurance status was a key socioeconomic determinant in the management and outcomes of patients with MSI-positive rectal adenocarcinoma. Privately insured patients were more likely to receive evidence based, resource-intensive care, including neoadjuvant radiation, minimally invasive and sphincter-sparing procedures, and experienced lower perioperative mortality and improved long-term survival. In contrast, area of residence and facility type had limited impact, suggesting that disparities in outcomes were driven primarily by insurance-related access to care rather than geographic or institutional differences. These disparities clearly need to be addressed.

Figure
Kaplan-Meier survival analysis of patients with locally advanced MSI positive rectal cancer stratified by insurance types and area of residence