About this Research Topic
State-of-the-art radiation oncology technology is offering ultra-precise dose-delivery and target-definition, and has paved the path for (re-) introducing high-dose regimens in the clinics. By now, an array of clinical studies have demonstrated that the intensified high-dose radiotherapy (HD-RT) regimens typically delivered by Stereotactic ablative Body Radiotherapy (SABR) is resulting in unprecedented high rates of local tumor control, often reaching levels comparable to surgical resection. Due to the proven clinical success of high-dose RT regimens, SABR is increasingly applied to primary and secondary lung tumors, liver tumors and spinal metastases. Beyond its intended use for local tumor ablation, HD-RT has also gained status as a therapeutic option that, in conjunction with systemic treatment strategies, may be used for metastatic and recurrent disease.
HD-RT differs substantially from standard protracted 2 Gy-regimens, and is generally defined as treatment regimens with high-dose per fraction (5-30Gy) in few fractions (1-5). These definitions are inaccurate and too broad in biological terms, since exerted effects may differ considerably between different RT-regimens within those margins. Additionally, fraction intervals and total dose are relevant parameters that could influence the biological responses to HD-RT. Thus, in biological terms, the current application of SABR has not reached a point of optimized refinement.
In this research topic we aim at gathering experiences and opinions of scientists dealing with HD-RT in order to systematize existing knowledge and to fine-tune HD-RT as a new treatment modality. This is a mandatory step to find optimal regimens that render maximal tumor control and minimal toxicity. Furthermore, this research topic should consider also the combination of HD-RT with chemotherapy, targeted therapies or immunotherapy. Emphasis should be put on details such as threshold-doses, single versus oligo-fractions, fraction intervals and total radiation dose. The biological spectrum covered should be as wide as possible, including immunological responses, but also effects induced in vasculature, tumor stroma, inflammatory cells, patterns of hypoxia, and so on. Ideally, scientists from different disciplines should contribute to this research topic in order to combine knowledge coming from clinical observations, experimental animal research and in vitro cell culture research.
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