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Effects of incidental low-dose radiation on abscopal responses after stereotactic body radiotherapy in patients with metastatic cancer: a retrospective real-world analysis

delete2025-11-27
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PRE
AI
J
Jae Sik Kim
J
Jun Yeong Song
B
Bum‐Sup Jang
B
Byoung Hyuck Kim *
DOI:10.1007/s10585-025-10381-ydelete
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Abstract

Abstract

En 中文
Although the abscopal effect is a rare phenomenon, preclinical and clinical studies have suggested that low-dose radiation may modulate the tumor microenvironment and enhance immune activation. We investigated the effect of incidental low-dose radiation on abscopal responses in patients with metastatic cancer treated with stereotactic body radiotherapy (SBRT). We retrospectively analyzed 39 patients with metastatic cancer who underwent SBRT for a single lesion with additional non-target lesions and received incidental low-dose radiation between 2010 and 2022. Tumor responses in these non-target lesions were evaluated within 3 months of SBRT and predictors of the abscopal effect were explored. At a median follow-up of 13.9 months, patients experiencing the abscopal effect (23.1%) showed significantly improved 1-year progression-free survival compared to those without it, while the 1-year overall survival showed a favorable trend without statistical significance. Among the 79 non-target lesions, those receiving incidental very low-dose radiation (< 0.5 Gy) demonstrated a significantly higher likelihood of an abscopal response than those receiving no radiation (odds ratio [OR] 9.707, p = 0.041). Higher pre-SBRT lymphocyte counts (> 2,000/μL) were also associated with an increased abscopal response (OR 7.782, p = 0.048). Conversely, pre-SBRT systemic therapy was inversely associated with abscopal response (OR 0.182, p = 0.034). Unintended low-dose radiation may exert an abscopal effect in patients with metastatic cancer treated with SBRT. This effect was linked to improved progression-free survival, indicating a possible clinical benefit. Further studies are required to confirm these results, which may inform SBRT planning strategies.
Keywords:
Abscopal effect
Low-dose radiation
Lymphocyte count
Metastatic cancer
Progression-free survival
Stereotactic body radiotherapy

Journal

C
Clinical and Experimental Metastasis
IF:
3.2
Papers:
2.4K
Citations:
3.4K

Organization

D
Department of Radiation Oncology
Scholars:
2.0K
Papers: 697
Citations: 4
S
soonchunhyang university seoul hospital
Scholars:
29
Papers: 20
Citations: 0
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