Despite the common application and considerable efforts to achieve precision radiotherapy (RT) in several types of cancer, RT has not yet entered the era of precision medicine; the ability to predict radiosensitivity and treatment responses in tumors and normal tissues is lacking. Therefore, development of genome-based methods for individual prognosis in radiation oncology is urgently required. Traditional DNA sequencing requires tissue samples collected during invasive operations; therefore, repeated tests are nearly impossible. Intra- and inter-tumoral heterogeneity may undermine the predictive power of a single assay from tumor samples. In contrast, analysis of circulating tumor DNA (ctDNA) allows for non-invasive and near real-time sampling of tumors. By investigating the genetic composition of tumors and monitoring dynamic changes during treatment, ctDNA analysis may potentially be clinically valuable in prediction of treatment responses prior to RT, surveillance of responses during RT, and evaluation of residual disease following RT. As a biomarker for RT response, ctDNA profiling may guide personalized treatments. In this review, we will discuss approaches of tissue DNA sequencing and ctDNA detection and summarize their clinical applications in both traditional RT and in combination with immunotherapy.

中文翻译：

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开发更灵敏的基因组方法来检测精确放射肿瘤学中的放射反应：从组织DNA分析到循环肿瘤DNA。

尽管在几种类型的癌症中有广泛的应用并为实现精确放射治疗（RT）做出了巨大努力，但RT尚未进入精确医学时代。缺乏在肿瘤和正常组织中预测放射敏感性和治疗反应的能力。因此，迫切需要开发基于基因组的放射肿瘤学个体预后方法。传统的DNA测序需要在侵入性手术中收集组织样本。因此，重复测试几乎是不可能的。肿瘤内和肿瘤间的异质性可能会破坏从肿瘤样品中进行单一检测的预测能力。相反，对循环肿瘤DNA（ctDNA）的分析允许对肿瘤进行非侵入性和近实时采样。通过研究肿瘤的遗传组成并监测治疗过程中的动态变化，ctDNA分析在预测RT之前的治疗反应，RT期间的反应监测以及RT之后的残留疾病评估方面可能具有临床价值。作为RT反应的生物标志物，ctDNA分析可能会指导个性化治疗。在这篇综述中，我们将讨论组织DNA测序和ctDNA检测的方法，并总结它们在传统RT和免疫治疗中的临床应用。