Can Patients With Recurrent or Primary Squamous Cell Carcinoma of the Anus in a Previously Irradiated Pelvis Receive Definitive Reirradiation

Authors

Jordan McDonald
Ethan P Damron
Prajnan Das
Eugene J Koay
Ethan B Ludmir
Bruce D Minsky
Sonal S Noticewala
Grace L Smith
Craig Messick
Van K Morris
Emma B Holliday

Language

English

Publication Date

2-1-2026

Journal

Advances in Radiation Oncology

DOI

10.1016/j.adro.2025.101952

PMID

41726003

PMCID

PMC12918202

PubMedCentral® Posted Date

11-9-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Purpose: Although salvage surgery is the standard of care for locoregionally recurrent anal cancer, few local options exist for inoperable pelvic recurrences. Newly diagnosed anal cancer arising in a previously irradiated field also provides a unique treatment challenge, as delivery of standard doses would result in unsafe cumulative dose to pelvic structures. We aimed to evaluate efficacy and toxicity of a hyperfractionated accelerated reirradiation (reRT) regimen for such patients.

Methods and materials: Patients treated with hyperfractionated accelerated reRT at a single institution between 2005 and 2024 for nonmetastatic inoperable locoregionally recurrent anal cancer or primary anal cancer in a previously irradiated field were included. The reRT regimen consisted of 1.5 Gy in twice daily fractions separated by 6 hours to a median (range) of 39 (30-51) Gy. Complete clinical response rates, recurrence rates, and toxicities were reported.

Results: The median (IQR) follow-up was 13.4 (7.5-42.2) months. Twenty-six (74.3%) patients were treated with reRT for recurrent anal cancer, and 9 (25.7%) patients were treated with reRT for a new squamous cell carcinoma of the anus (SCCA) primary after prior pelvic radiation. The complete clinical response rate was 46.2% among patients with recurrent anal cancer and 77.8% among patients with a new SCCA primary after prior pelvic radiation. Two-year locoregional recurrence rate was 64.0% among patients with recurrent anal cancer and 22.0% among patients treated with reRT for a new SCCA primary after prior pelvic radiation. Eight patients (22.9%) developed acute grade 3 toxicity and 10 (28.6%) developed late grade 3-4 toxicity.

Conclusions: Hyperfractionated accelerated reRT results in promising complete clinical response rates that appear to translate into durable pelvic control for patients with recurrent anal cancer or a new SCCA primary after prior pelvic radiation. Acute toxicity appears similar to initial standard chemoradiation, but limiting reRT doses to 39 Gy may reduce the risk of serious late toxicity.

Published Open-Access

yes

Recommended Citation

McDonald, Jordan; Damron, Ethan P; Das, Prajnan; et al., "Can Patients With Recurrent or Primary Squamous Cell Carcinoma of the Anus in a Previously Irradiated Pelvis Receive Definitive Reirradiation" (2026). Faculty, Staff and Student Publications. 5991.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/5991