Editorial: 365 days of progress in radiation oncology

COPYRIGHT © 2023 Kinsella. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Editorial PUBLISHED 21 March 2023 DOI 10.3389/fonc.2023.1179316

clinical human cancer models. Alden et al. from SUNY Upstate Medical University provide an overview of glutamine metabolism as it relates to ionizing radiation resistance focusing on effects on DNA repair and anti-cancer immunity based on recent literature. Additionally, they highlight the "bench-to-bedside" on-going clinical trials of specific glutamine metabolism inhibitors and radiation therapy in IDH-mutant gliomas and locally advanced cervix cancer based on the pre-clinical literature.
The fourth Research Topic paper by Chen et al. from Xiangya Hospital in China involves a radiation therapy treatment and clinical outcomes study in patients with non-metastatic, late Tstage nasopharyngeal cancer. They compare outcomes using volumetric modulated arc therapy (VMAT) versus tomotherapy. Such patients present major challenges for modern day radiation therapy treatment planning because of the primary tumor location and multiple loco-regional normal tissues. Using a 1:1 propensity score match of 171 patients in this single institution study, the authors demonstrate that tomotherapy is superior to VMAT in terms of most normal tissue (or organs at risk, OAR) dosimetric parameters with a decrease in acute mucositis (Grade ≥ 3; 22 vs 41%; p=0.038) and a higher clinical complete response (CR= 83 vs 67%; p=0.046). No differences in local control nor overall survival were found. However, these authors also suggest that a hybrid radiation treatment planning combining intensity-modulated radiation therapy (IMRT) and VMAT in locally advanced nasopharyngeal carcinoma may be equivalent or superior to tomotherapy in terms of toxicities and clinical outcome.
The fifth paper involves a review article by Xie et al. which provides an update of hydrogel-based local drug/biologic/ radioisotope delivery systems to enhance post-operative radiation therapy. Hydrogels are a new class of local drug/biologic/ radioisotope delivery with theoretically provide 3 major advantages compared to systemic delivery including biocompatibility, high loading capacity and sustained local drug release. They describe different classifications of hydrogels based on physical material, cross-linking patterns, electric charge and polymeric composition. They illustrate pre-clinical use of hydrogels for local delivery of radioisotopes including I 125 , I 131 and Rh 188 as well as immune modulators including PD-L1 antibodies. They also cite the complexity in synthesis, delivery and local toxicities of the hydrogel delivery systems.
The final paper in this FRO Research Topic by Wang et al. describes the impact of changes in absolute eosinophil counts measured weekly during and for one month following definitive radiation therapy (> 46 GY total dose) as a clinical biomarker predicting overall survival (OS) and progression free survival (PFS) in patients with locally advanced non-small cell lung cancer (NSCLC). In a retrospective, single institution review of 240 patients from Chongqing University in China, an eosinophil increase ration (EIR) of ≥ 1.43 at 1 month post-treatment was predictive of favorable clinical outcomes (5 year OS: 21% vs 10%, p<0.001 and 5 year PFS: 10% vs 8%, p=0.014). The use of concomitant versus sequential chemotherapy did not impact PFS. Interestingly, the heart mean dose and heart V10 were directly associated with a lower EIR but did not impact OS and PFS in this retrospective review. Additionally, no analysis of key molecular markers (EGFR, ROS1) nor immune status (PD-1, PD-L1) were part of this retrospective review.
In summary, I highlight the key factors from the 6 manuscripts published under the wide-ranging FRO Research Topic, "365 Days of Progress in Radiation Oncology." As expected, there are no overall take-home messages nor common lessons from these manuscripts. Hopefully, they provide a ground base for future basic and clinical research in radiation oncology.

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