EPD505 - Salvage Immunotherapy as an Acceptable Alternative Therapy to Abdominoperineal Resection in Anal Squamous Cell Carcinoma with Persistent Disease After Chemoradiation

ePoster of Distinction Presenter(s)

• 

  Marianna Sarkissyan, MD

  Resident-Physician
  Harbor UCLA Medical Center
  Harbor UCLA Medical Center
  Rancho Palos Verdes, CA, 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

Author(s)

• MJ

  Melissa Justo, MD

  Resident-Physician
  University of California Los Angeles
  Los Angeles, California, United States

  Disclosure information not submitted.
• SS

  Sara Sakowitz, MD

  Resident-Physician
  Massachusetts General Hospital
  Los Angeles, California, United States

  Disclosure information not submitted.
• PB

  Peyman Benharash, MD

  Associate Professor of Cardiothoracic Surgery
  David Geffen School of Medicine at UCLA
  Los Angeles, California, United States

  Disclosure information not submitted.

Senior Author(s)

• LH

  Lee Hanjoo, MD, FASCRS

  Assistant Professor
  Harbor-UCLA Medical Center
  Torrance, California, United States

  Disclosure information not submitted.

Purpose/Background: Patients with squamous cell carcinoma of the anus (SCCA) receive chemoradiation as primary therapy, but 10-30% still have residual disease. Abdominoperineal resection(APR) has traditionally been the standard salvage therapy but is associated with significant morbidity. Emerging yet limited data have suggested immunotherapeutic agents may be effective as an alternative salvage modality to APR. This is a nationwide study comparing survival outcomes after salvage APR vs. immunotherapy among ASCC patients who have residual disease after receiving chemoradiation.

Methods/Interventions: This was a retrospective analysis of the 2016-2022 National Cancer Database and included any T, N+, M0 ASCC adult patients who had undergone chemoradiation. Patients with residual disease were divided into those who underwent salvage APR (APR cohort) or immunotherapy (IO cohort). Kaplan-Meier was used to evaluate survival at 1- and 3- years. Hazards of survival at 3-years was assessed via Cox proportional hazard models adjusting for: age, sex, race, insurance coverage, Charlson-Deyo comorbidity index, AJCC 8th ed. clinical T stage, hospital type and year of diagnosis.

Results/Outcomes: A total of 256 patients were identified, 202 were APR and 54 were IO. IO more frequently presented with smaller tumors but had advanced nodal disease. While 1 year survival was similar (P=0.46), APR had inferior overall survival at 3 years (P=0.004). Risk-adjusted analysis confirmed IO's superior 3-year survival (HR 0.33, 95% CI 0.11-0.98, P=0.05), which remained significant on landmark analysis (P=0.005).

Conclusion/Discussion: Immunotherapy as a salvage modality may be an acceptable alternative to APR for ASCC patients who underwent chemoradiation but had residual disease.

Figure 1. Kaplan-Meier Overall Survival Following Salvage APR vs Immunotherapy
Caption: 1-year overall survival is comparable between APR (96%) and IO (94)%, Log Rank P=0.46. 3-Year Overall Survival shows IO had better survival (87%) compared to APR (62%), Log Rank P=0.004 in favor of IO. Kaplan-Meier time-to-event curves are presented with 95% confidence intervals. The at-risk numbers below each timepoint indicate the actual number of patients remaining at risk.