Application of circulating tumor DNA as a non-invasive tool for monitoring the progression of colorectal cancer

Background: Liquid biopsy has been proposed to be a promising noninvasive tool to obtain information on tumor progression. Through a clinical observation of a case series of 6 consecutive patients, we aim to determine the value of circulating tumor DNA (ctDNA) for monitoring the tumor burden during the treatment of colorectal cancer (CRC). Materials and methods: We used capture sequencing of 545 genes to identify somatic alternations in primary tumor tissues of the six CRC patients who underwent radical surgery and in 23 plasma samples collected at serial time points. We compared the mutation patterns and variant allele frequencies (VAFs) between the matched tissue and the plasma samples and evaluated the potential advantage of using ctDNA as a better tumor load indicator to detect disease relapse over carcinoembryonic antigen (CEA), cancer antigen (CA) 19-9 and imaging studies. Results: We identified low-frequency mutations with a mean VAF of 0.88% (corresponding to a mean tumor bu...研究背景：液体活检（Liquid biopsy）已被提出作为一种极具前景的非侵入性工具，可用于获取肿瘤进展相关信息。本研究通过对6例连续入组患者的病例系列开展临床观察，旨在探讨循环肿瘤DNA（ctDNA）在结直肠癌（CRC）治疗过程中监测肿瘤负荷的临床价值。 材料与方法：本研究采用545基因捕获测序技术，对6例接受根治性手术的CRC患者的原发肿瘤组织，以及连续时间点采集的23份血浆样本中的体细胞变异进行鉴定。我们对比了匹配的组织与血浆样本的突变模式及变异等位基因频率（VAFs），并评估了相较于癌胚抗原（CEA）、糖类抗原（CA）19-9及影像学检查，采用ctDNA作为更优的肿瘤负荷指标以检测疾病复发的潜在优势。 研究结果：本研究共鉴定出平均变异等位基因频率为0.88%的低频突变（对应平均肿瘤负荷……）