Background RAS mutations are currently sought for in tumor samples, which takes a median of almost 3 weeks in western European countries. This creates problems in clinical situations that require urgent treatment and for inclusion in therapeutic trials that need RAS status for randomization. Analysis of circulating tumor DNA might help to shorten the time required to determine RAS mutational status before anti-epidermal growth factor receptor antibody therapy for metastatic colorectal cancer. Here we compared plasma with tissue RAS analysis in a large prospective multicenter cohort. Patients and methods Plasma samples were collected prospectively from chemotherapy-naive patients and analyzed centrally by next-generation sequencing (NGS) with the colon lung cancer V2 Ampliseq panel and by methylation digital PCR (WIF1 and NPY genes). Tumoral RAS status was determined locally, in parallel, according to routine practice. For a minimal κ coefficient of 0.7, reflecting acceptable concordance (precision ± 0.07), with an estimated 5% of non-exploitable data, 425 subjects were necessary. Results From July 2015 to December 2016, 425 patients were enrolled. For the 412 patients with available paired plasma and tumor samples, the κ coefficient was 0.71 [95% confidence interval (CI), 0.64-0.77] and accuracy was 85.2% (95% CI, 81.4% to 88.5%). In the 329 patients with detectable ctDNA (at least one mutation or one methylated biomarker), the κ coefficient was 0.89 (95% CI, 0.84-0.94) and accuracy was 94.8% (95% CI, 91.9% to 97.0%). The absence of liver metastases was the main clinical factor associated with inconclusive circulating tumor DNA results [odds ratio = 0.11 (95% CI, 0.06-0.21)]. In patients with liver metastases, accuracy was 93.5% with NGS alone and 97% with NGS plus the methylated biomarkers. Conclusion This prospective trial demonstrates excellent concordance between RAS status in plasma and tumor tissue from patients with colorectal cancer and liver metastases, thus validating plasma testing for routine RAS mutation analysis in these patients. Clinical Trial registration Clinicaltrials.gov, NCT02502656.

中文翻译：

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转移性结直肠癌患者循环肿瘤DNA中的RAS突变分析：AGEO RASANC前瞻性多中心研究。

目前正在肿瘤样品中寻找背景RAS突变，在西欧国家中值需要将近3周的时间。这在需要紧急治疗的临床情况下以及在需要RAS身份进行随机化的治疗性试验中纳入问题。循环肿瘤DNA的分析可能有助于缩短转移性大肠癌抗表皮生长因子受体抗体治疗之前确定RAS突变状态所需的时间。在这里，我们将血浆与组织RAS分析在大型前瞻性多中心队列中进行了比较。患者和方法前瞻性收集未经化疗的患者的血浆样品，并通过带有结肠癌V2 Ampliseq面板的下一代测序（NGS）和甲基化数字PCR（WIF1和NPY基因）进行集中分析。根据常规做法，同时确定肿瘤的RAS状态。对于最小的κ系数0.7，反映出可接受的一致性（精度±0.07），估计有5％的无法利用的数据，则需要425名受试者。结果2015年7月至2016年12月，共招募425例患者。对于412位血浆和肿瘤样本配对的患者，κ系数为0.71 [95％置信区间（CI），0.64-0.77]，准确度为85.2％（95％CI，81.4％至88.5％）。在329例可检测ctDNA（至少一种突变或一种甲基化生物标记）的患者中，κ系数为0.89（95％CI，0.84-0.94），准确度为94.8％（95％CI，91.9％至97.0％）。没有肝转移是与不确定的循环肿瘤DNA结果相关的主要临床因素[比值比= 0.11（95％CI，0.06-0。）。21）]。在有肝转移的患者中，单独使用NGS的准确性为93.5％，而使用NGS加甲基化生物标记物的准确性为97％。结论该前瞻性试验证明了大肠癌和肝转移患者血浆和肿瘤组织中RAS状态之间的极佳一致性，从而验证了血浆检测可用于这些患者的常规RAS突变分析。临床试验注册Clinicaltrials.gov，NCT02502656。