EQD2-adjusted mean lung dose and symptomatic pneumonitis after thoracic radiotherapy following immune checkpoint inhibitors in lung cancer: a single-center retrospective cohort study
- 1Department of Radiation Oncology, Fuzhou Pulmonary Hospital of Fujian Province, Teaching Hospital of Fujian Medical University , , ,
- 2Department of Oncology, Fuzhou Pulmonary Hospital of Fujian Province, Teaching Hospital of Fujian Medical University , , ,
Abstract
Background: Evidence on pneumonitis after thoracic radiotherapy following immune checkpoint inhibitor (ICI) exposure remains limited. We examined associations with voxel-wise EQD2 mean lung dose (MLD EQD2 ) and the ICI–radiotherapy interval.
Methods: This single-center retrospective cohort included 98 patients in a 90-day competing-risk analysis of grade ≥2 radiation pneumonitis (CTCAE), comprising 26 pneumonitis events, 70 event-free observations, and two deaths before pneumonitis. Archived DICOM doses were converted voxel-wise using α/β = 3 Gy. Cumulative incidence was estimated using the Aalen–Johansen method, and Fine–Gray regression included continuous MLD EQD2 and treatment interval. Supplementary logistic analyses included 96 patients.
Results: The 90-day pneumonitis cumulative incidence was 26.5% (95% CI 17.7%–35.3%). The adjusted subdistribution hazard ratio (SHR) for MLD EQD2 was 1.339 per Gy (95% CI 1.113–1.612; P = 0.002). The interval SHR was 0.784 per 10 days (95% CI 0.639–0.963; P = 0.020). Physical MLD showed a consistent association (SHR 1.197 per Gy, 95% CI 1.036–1.382; P = 0.015).
Conclusion: Higher MLD EQD2 and shorter treatment intervals were associated with grade ≥2 symptomatic pneumonitis in this treatment sequence. Clinical ascertainment and dose-reconstruction uncertainties limit interpretation. The absence of an ICI-naive comparator precludes conclusions about ICI-specific radiosensitization. Prospective validation is required before these associations can inform dose constraints or treatment scheduling.
Related
- Dosimetric Comparison of Intensity-Modulated Radiotherapy and Four-Field Three-Dimensional Conformal Radiotherapy in the Management of Prostate Cancer: A Retrospective Dual-Centre Analysis
- Retrospective intrafraction motion verification using triggered kilovoltage images during bone metastases stereotactic body radiotherapy
- Six-Fraction Ultra-Hypofractionated Radiotherapy for Tumours Adjacent to or Involving the Brachial Plexus: A Retrospective Cohort Study.
- ExacTrac Dynamic Surface-Guided Setup Versus Tattoo-Based Positioning in Breast Cancer Radiotherapy: A Retrospective Comparison of Setup Accuracy and Preparation Time
- Editorial: Next-generation radiotherapy for prostate cancer: precision, personalization, and technological advances
BibTeX
@article{li2026eqd2adjusted,
title = {{EQD2-adjusted mean lung dose and symptomatic pneumonitis after thoracic radiotherapy following immune checkpoint inhibitors in lung cancer: a single-center retrospective cohort study}},
author = {Xiqing Li and Libin Liu and Nuo Zheng and Nila Wang and Tingxiong Xiao and Xiaolong Lin and Haidun Chen and Qin Shi and Yuyin Le},
journal = {Frontiers in oncology},
year = {2026},
month = oct,
doi = {10.3389/fonc.2026.1923622},
url = {https://europepmc.org/article/PMC/PMC13690549},
note = {CC BY},
}
RIS
TY - JOUR
TI - EQD2-adjusted mean lung dose and symptomatic pneumonitis after thoracic radiotherapy following immune checkpoint inhibitors in lung cancer: a single-center retrospective cohort study
AU - Xiqing Li
AU - Libin Liu
AU - Nuo Zheng
AU - Nila Wang
AU - Tingxiong Xiao
AU - Xiaolong Lin
AU - Haidun Chen
AU - Qin Shi
AU - Yuyin Le
PY - 2026
DA - 2026/10/09
JO - Frontiers in oncology
DO - 10.3389/fonc.2026.1923622
UR - https://europepmc.org/article/PMC/PMC13690549
AB - Background: Evidence on pneumonitis after thoracic radiotherapy following immune checkpoint inhibitor (ICI) exposure remains limited. We examined associations with voxel-wise EQD2 mean lung dose (MLD EQD2 ) and the ICI–radiotherapy interval. Methods: This single-center retrospective cohort included 98 patients in a 90-day competing-risk analysis of grade ≥2 radiation pneumonitis (CTCAE), comprising 26 pneumonitis events, 70 event-free observations, and two deaths before pneumonitis. Archived DICOM doses were converted voxel-wise using α/β = 3 Gy. Cumulative incidence was estimated using the Aalen–Johansen method, and Fine–Gray regression included continuous MLD EQD2 and treatment interval. Supplementary logistic analyses included 96 patients. Results: The 90-day pneumonitis cumulative incidence was 26.5% (95% CI 17.7%–35.3%). The adjusted subdistribution hazard ratio (SHR) for MLD EQD2 was 1.339 per Gy (95% CI 1.113–1.612; P = 0.002). The interval SHR was 0.784 per 10 days (95% CI 0.639–0.963; P = 0.020). Physical MLD showed a consistent association (SHR 1.197 per Gy, 95% CI 1.036–1.382; P = 0.015). Conclusion: Higher MLD EQD2 and shorter treatment intervals were associated with grade ≥2 symptomatic pneumonitis in this treatment sequence. Clinical ascertainment and dose-reconstruction uncertainties limit interpretation. The absence of an ICI-naive comparator precludes conclusions about ICI-specific radiosensitization. Prospective validation is required before these associations can inform dose constraints or treatment scheduling.
SN - 2234-943X
ER -