EPD506 - Clinical Calculator for Estimating Recurrence-free Survival Among Patients With Stage I-III Anal Squamous Cell Carcinoma Who Completely Respond to Chemoradiation

Monday, May 11, 2026

4:08 PM - 4:13 PM ET

ePoster of Distinction Presenter(s)

Roni Y. Rosen, MD

General Surgery Resident
Hackensack University Medical Center
Hackensack University Medical Center, NJ
Tenafly, NJ, United States

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

Author(s)

ES

Erin P. Santos, MD

Research Fellow
Memorial Sloan Kettering Cancer Center
Houston, Texas, United States

Disclosure information not submitted.
Janet Alvarez, MD (she/her/hers)

Research Scholar
Memorial Sloan-Kettering Cancer Center
New York, NY, United States

Disclosure information not submitted.
Christina I. Lee, MD

Research Scholar
Memorial Sloan Kettering
NA
New York, NY, United States

Disclosure information not submitted.
MA

Mohammad Ali Abbass, MD MPH

Assistant Attending
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.
Georgios Karagkounis, MD

Assistant Attending
Memorial Sloan Kettering Cancer Center
Memorial Sloan Kettering
New York, NY, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
Maria Widmar, MD, MPH (she/her/hers)

Assistant Attending
Memorial Sloan Kettering Cancer Center
Weill Cornell Medical Center
New York, New York, United States

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

Iris H. Wei, MD

Assistant Attending
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.
J. Joshua Smith, MD, PhD

Professor and Chair, Colon and Rectal Surgery Department
MD Anderson Cancer Center
MD Anderson Cancer Center
Houston, TX, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no relevant relationships with ineligible companies.
Garrett M. M. Nash, MD, MPH

Vice Chair of Quality and Safety
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.
Martin R. Weiser, MD

Vice Chair for Faculty Affairs
Memorial Sloan Kettering Cancer Center
Cornell Medical College
New York, New York, United States

Disclosure information not submitted.
PR

Paul Romesser, MD

Attending
Memorial Sloan Kettering
New York, New York, United States

Disclosure information not submitted.
DR

Diana Roth O'Brien, MD, MPH

Assistant Attending Radiation Oncologist
Memorial Sloan Kettering
New York, New York, United States

Disclosure information not submitted.
CC

Christopher H. Crane, MD

Attending
Memorial Sloan Kettering Cancer Center
New York City, New York, United States

Disclosure information not submitted.
Andrea Cercek, MD

Associate Physician
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.
MS

Marina Shcherba, DO

Associate physician attending
MSKCC
Middletown, New Jersey, United States

Disclosure information not submitted.
LS

Leonard Saltz, MD

Attending Physician
Department of Medical Oncology, Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.
MG

Mithat Gonen, PhD

Attending Biostatistician
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.
Julio Garcia Aguilar

Disclosure information not submitted.

Senior Author(s)

Emmanouil Pappou, MD, PhD

Assistant Attending
Memorial Sloan Kettering Cancer Center
New York, New York, United States

Disclosure information not submitted.

All of the relevant financial relationships listed below have been mitigated.

Roni Y. Rosen, MD: This individual has no relevant relationships with ineligible companies.

Georgios Karagkounis, MD: This individual has no financial relationships with ineligible companies.

Maria Widmar, MD, MPH: This individual has no relevant relationships with ineligible companies.

J. Joshua Smith, MD, PhD: This individual has no relevant relationships with ineligible companies.

Purpose/Background: Anal squamous cell carcinoma (SCC) is rare, with rising incidence rates over the past two decades. Combined modality treatment achieves high rates of clinical complete response (CR), but recurrence after CR is associated with poor outcomes. Nomogram-based models have emerged to integrate multiple prognostic factors and improve individualized risk estimation. We aimed to develop and internally validate a nomogram to predict recurrence-free survival (RFS) in stage I-III anal SCC patients who achieved a complete response to definitive chemoradiation.

Methods/Interventions: We retrospectively identified 490 patients with stage I-III anal SCC treated with definitive chemoradiation between 2007 and 2020. Patients with stage IV disease, synchronous malignancies, or insufficient follow-up were excluded. Clinical staging was standardized per AJCC 9th edition criteria. Candidate variables were assessed, and significant predictors of recurrence in multivariable analysis were included in the nomogram. The model was developed using RFS as the endpoint. We evaluated discrimination with the concordance index (c-index) and calibration by comparing predicted vs observed RFS in calibration plots. Internal validation was performed via bootstrap resampling. Kaplan-Meier analysis was used to estimate local and distant metastasis-free as well as disease-free survival rates for the entire cohort.

Results/Outcomes: The final clinical calculator incorporated two predictors: AJCC T category and N category at diagnosis. The nomogram demonstrated a c-index of 0.65 (95% confidence interval [CI] 0.604-0.696) for RFS, indicating moderate discrimination. This slightly exceeded the performance of AJCC staging alone (c-index 0.628, 95% CI 0.582-0.674). Calibration plots showed good agreement between predicted and observed RFS, indicating that nomogram predictions were well-calibrated. The 3-year local and distant recurrence-free survival rates for the entire cohort were 90% (95% CI 87.3-92.7%) and 91.1% (95% CI 88.5-93.7%), respectively. The 3-year disease specific survival was 97.0% (95% CI 95.5-98.6%).

Conclusion/Discussion: Our prognostic nomogram for anal SCC patients achieving CR after chemoradiation provides an evidence-based tool for individualized risk stratification. It addresses the need for personalized surveillance by identifying patients at higher risk of recurrence. Consistent with prior models in gastrointestinal cancers, this nomogram showed a modest improvement in predictive accuracy over TNM staging. Such risk estimation can inform patient-physician discussions and guide post-treatment surveillance strategies.

Figure 1: Anal squamous cell carcinoma nomogram for estimating recurrence-free survival

The top scale corresponds to the number of points that should be added for each risk factor (T and N stage) to yield the total number of points that correspond to the recurrence-free survival (RFS) rates below the total points scale.