Main Session
Sep
28
PQA 02 - Lung Cancer/Thoracic Malignancies, Patient Reported Outcomes/QoL/Survivorship, Pediatric Cancer
2526 - Voxel-Based Analysis of Cardiac Radiosensitivity: Impact of Consolidation Immunotherapy after Chemoradiotherapy
Presenter(s)
Hong In Yoon, MD, PhD - Yonsei University College of Medicine, Seoul, Seoul
Y. Kim1, H. I. Yoon2, and C. Grassberger3; 1Department of Radiation Oncology, University of Washington/Fred Hutchinson Cancer Center, Seattle, WA, 2Department of Radiation Oncology, Yonsei Cancer Center, Heavy Ion Therapy Research Institute, Yonsei University College of Medicine, Seoul, Korea, Republic of (South), 3Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
Purpose/Objective(s):
This study investigates whether immune checkpoint inhibitor (ICI) exposure after chemoradiotherapy (CRT) alters the critical cardiac subregion associated with radiation-induced heart disease (RIHD) in non-small cell lung cancer (NSCLC) patients.Materials/Methods:
This retrospective study focuses on non-small cell lung cancer patients who underwent CRT at a single institution between January 2015 and December 2019, among whom 67 patients exhibited a PD-L1 >1% and subsequently received consolidation ICI after CRT. RIHD, defined as major adverse cardiac events or atrial fibrillation, was the primary endpoint. A voxel-based analysis (VBA) was used to determine cardiac subregion doses correlated to RIHD for each group. Additionally, cardiac contours were collected including the entire heart, chambers, major coronary arteries, and conduction nodes. Fine-Gray analysis assessed associations between RIHD and cardiac subregion doses, accounting for death as a competing risk.Results:
RIHD occurred in 39 patients (17.8%) with no significant difference between CRT and CRT+ICI groups (19.9% vs. 11.1%, respectively) in cumulative incidence. Cardiac subregion doses were similar between groups. In CRT patients, voxel-based analysis (VBA) showed a strong signal near the base of the heart, and multivariable analysis identified sinoatrial node (SAN) dose as a significant RIHD predictor (HR=1.02 per Gy, 95% CI [1.01-1.03], p=0.004). In CRT+ICI patients, left ventricle (LV) dose was a significant predictor (HR=1.06 per Gy, 95% CI [1.02-1.1], p=0.006) in multivariable Fine-Gray analysis, but VBA did not reveal a strong signal. Median radiation doses to the SAN and LV were 13.5 Gy [IQR 4.7–28.7 Gy] and 3.9 Gy [IQR 1.0–8.3 Gy], respectively.Conclusion: ICI exposure may alter cardiac toxicity patterns post-CRT. While the base-of-heart dose correlated with RIHD in CRT patients, no strong dose-response relationship was observed in CRT+ICI patients according to VBA. A larger CRT+ICI cohort is needed to confirm statistical significance of it.
Abstract 2526 - Table 1: Multivariable Fine-Gray analysis for CRT and CRT+ICI group respectively | CRT | CRT+ICI | |||
| variables | HR (95% CI) | p value | HR (95% CI) | p value |
| Age | 1.03 (1-1.06) | 0.093 | 1.05 (1-1.1) | 0.038 |
| Sex | 0.91 (0.79-1.05) | 0.21 | ||
| Diabetes | 1.88 (1.22-2.9) | 0.004 | ||
| T stage | 1.48 (1.14-1.91) | 0.003 | ||
| N stage | 1.56 (1.19-2.03) | 0.001 | ||
| LV dose | 1.06 (1.06-1.1) | 0.006 | ||
| SAN dose | 1.02 (1.01-1.03) | 0.004 | ||