Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster display session

5035 - The frequency of RAS mutation in circulating tumor DNA predicts worse survival in patients with mCRC


09 Sep 2017


Poster display session


Liu Yang


Annals of Oncology (2017) 28 (suppl_5): v158-v208. 10.1093/annonc/mdx393


L. Yang, Y. Cai, J. Zhang, H. Hu, Z. Wu, R. Deng, Y. Deng

Author affiliations

  • Medical Oncology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 - Guangzhou/CN


Abstract 5035


RAS mutations predict a worse prognosis in metastatic colorectal cancer(mCRC). However, there are few findings regarding the prognostic value of RAS mutations in circulating tumor DNA (ctDNA). We aimed to compare the concordance of genomic alterations between ctDNA and tissue biopsies and assess the prognostic value of RAS mutations in ctDNA.


Gene mutational status in plasma and tissue were evaluated in mCRC patients by next-generation sequencing (NGS). Kaplan-Meier curve and Cox regression model were used to compare the progressive free survival (PFS) between different level of RAS mutations frequency.


of NGS testing from tumor tissue and ctDNA from 110 sequential mCRC patients were compared. Analysis of 6 gene in baseline tissue and plasma samples showed a 67.3% overall agreement. Concordance between the two platforms for KRAS, NRAS, BRAF, PIK3CA, SMAD4 and FBXW7 mutations, were 80.0%, 98.2%,97.2%,91.8%,69.1%,93.6% and 96.4%, respectively. RAS mutation rate in tissue and ctDNA were 48.1% and 29.1%. Fifty-nine patients were detected RAS mutation in tumor tissue, only thirty-six patients with plasma RAS mutation. One patient was detected ctDNA RAS mutation without mutation in tissue. Across plasma RAS gene, sensitivity and specificity were 61.0% and 99.3%, respectively. With a 48.2% cut-off rate, we divided 59 tissue RAS mutation patients into two different ctDNA RAS mutation groups(high frequency and low frequency group. Median PFS in high frequency group was 1.9 months and in low frequency group was 4.8 months(P = 0.002). In multivariate analysis considering other clinical factors(i.e. synchronous or metachronous metastasis, solitary and multiple metastases and CEA level, high ctDNA KRAS mutation frequency was independent adverse prognostic factor (HR 4.09,95% CI 1.61-10.40,p=0.003) for PFS in tissue KRAS mutation patients.


Plasma and tissue NGS testing have a high concordance in genomic alterations. Higher rate of baseline KRAS mutation frequency predicts worse prognosis in mCRC. Both plasma and tissue NGS may be necessary to describe the complex biology of mCRC.Circulating tumor DNA testing could be a viable alternative for genotyping of mCRC and recommended for routine clinical practice.

Clinical trial identification


Legal entity responsible for the study





All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.