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Radiation-Induced Lymphopenia is a Causal Mediator of Survival After Chemoradiation Therapy for Esophagus Cancer.
Chen, Yiqing; Chu, Yan; van Rossum, Peter S N; Grassberger, Clemens; Lin, Steven H; Mohan, Radhe; Hobbs, Brian P.
Afiliação
  • Chen Y; Department of Biostatistics and Data Science, University of Texas Health Science Center, Houston, Texas.
  • Chu Y; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
  • van Rossum PSN; School of Biomedical Informatics, University of Texas Health Science Center, Houston, Texas.
  • Grassberger C; Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
  • Lin SH; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
  • Mohan R; Department of Radiation Oncology, Amsterdam UMC, Amsterdam, The Netherlands.
  • Hobbs BP; Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
Adv Radiat Oncol ; 9(10): 101579, 2024 Oct.
Article em En | MEDLINE | ID: mdl-39258141
ABSTRACT

Purpose:

Radiation-induced lymphopenia (RIL) is common during chemoradiation therapy. Severe lymphopenia is associated with reduced survival. Proton beam therapy (PBT), with its substantially more compact dose distributions, spares circulating lymphocytes and immune organs at risk to a greater extent than photon therapy. Recent studies comparing PBT to photon radiation therapy, specifically intensity-modulated radiation therapy (IMRT) for esophageal cancer (EC), showed that the incidence of grade 4 RIL (G4RIL) is significantly reduced among patients receiving PBT for EC. However, whether the extent of this reduction has a direct causative link with improved survival is unknown. This study applies causal mediation analysis to answer this question. Methods and Materials We retrospectively assessed 734 patients treated with concurrent chemoradiation therapy for biopsy-proven EC from 2004 to 2017. To address the potential for bias in the choice of radiation modality, propensity score analysis was used to evaluate and reduce imbalances between the PBT and IMRT cohorts. Causal mediation analysis was applied to decompose the total effect of radiation modality on overall survival (OS) into indirect (mediated through G4RIL) and direct effects.

Results:

We found that PBT was associated with a significantly lower incidence of G4RIL and prolonged OS compared with IMRT (odds ratio, 0.41; 95% CI, 0.28-0.60; P < .001). In the propensity-matched cohort of 506 patients (253 PBT, 253 IMRT), G4RIL risk reduction with PBT versus IMRT translated into a 5% reduction in the relative rate of death (P = .032). Mediation of G4RIL explained ∼14.5% of the difference in OS.

Conclusions:

G4RIL was found to mediate survival; however, a statistically significant direct effect of PBT on survival was not observed. In other words, the statistical significance of survival benefit from protons over photons in this EC cohort was lost in the absence of G4RIL risk reduction.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Adv Radiat Oncol Ano de publicação: 2024 Tipo de documento: Article País de publicação: Estados Unidos
Texto completo
Adicionar na Minha BVS
Imprimir
XML
PubMed Links
Buscar no Google

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Idioma: En Revista: Adv Radiat Oncol Ano de publicação: 2024 Tipo de documento: Article País de publicação: Estados Unidos