SO-24 Circulating tumor DNA variant allelic fraction as a surrogate for disease burden estimation in patients with RAS wild-type metastatic colorectal cancer: A secondary endpoint of the VALENTINO study

490 Background: It has been suggested that detection of circulating tumor DNA may be relevant in patients with metastatic colorectal cancer (mCRC). The main objective of the present study was to evaluate a method based on the TaqMan Mutation Detection Assay (TMDA) for the detection of circulating KRAS mutations in mCRC patients. Moreover, we also investigated the prognostic impact of the plasma cell-free DNA and the fraction of circulating KRAS mutations. Methods: The study was conducted from April to July 2013 and plasma samples were prospectively collected in a series of 35 mCRC patients treated with chemotherapy (CT). QIAamp Circulating Nucleic Acid kit was used for DNA extraction and Quant-iT High Sensitivity dsDNA Assay for cf-DNA quantification. Detection of circulating tumor DNA was based on the KRAS mutations detected in tumour and was performed in plasma by the castPCR Technology TMDA. Response to CT was assessed according to RECIST criteria. The results of plasma cf-DNA and level of mutant DNA fragments were correlated with response and 3-months survival. Results: We isolated and quantified plasma cf-DNA in all patients with a mean concentration of 106 ng/mL. Among them, 18 were wild-type and 17 mutated for KRAS in the tumour. Detection of circulating KRAS mutations was performed with TMDA in 23 patients (10 KRAS wild-type and 13 KRAS mutated). The sensitivity was 62% (8/13) and specificity 100% (0/10) with a level of circulating mutant DNA fragments ranging from 0 to 29%. Plasma cf-DNA and level of circulating mutant DNA were both significantly correlated with the 3-months survival (mean 36 versus 524 ng/mL, p=0.0015 and 2% versus 29%, p<0.0001). There was a non significant trend for response to CT (respectively p=0.14 and p=0.12). Conclusions: TMDA method is a simple, accurate and non-invasive tool for the detection of circulating tumor DNA. Our preliminary results also suggest that plasma cf-DNA and fraction of mutant DNA fragments could be prognostic markers in mCRC patients.

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RAS Mutations in Circulating Tumor DNA and Clinical Outcomes of Rechallenge Treatment With Anti-EGFR Antibodies in Patients With Metastatic Colorectal Cancer

JCO Precision Oncology ◽

10.1200/po.20.00109 ◽

2020 ◽

pp. 898-911

Author(s):

Yu Sunakawa ◽

Masato Nakamura ◽

Masahiro Ishizaki ◽

Masato Kataoka ◽

Hironaga Satake ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Clinical Outcomes ◽

Circulating Tumor Dna ◽

Wild Type ◽

Phase Ii Trials ◽

Ras Mutation ◽

Ras Mutations ◽

Ras Status ◽

Tumor Dna

PURPOSE Several trials have evaluated the efficacy of rechallenge treatment with anti–epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) in patients with metastatic colorectal cancer (mCRC). A recent trial indicated that RAS status in circulating tumor DNA (ctDNA) may potentially predict patients with RAS wild-type mCRC resistant to anti-EGFR mAb who would benefit from rechallenge treatment, and the findings should be further investigated. MATERIAL AND METHODS We enrolled patients whose plasma samples were collected in prospective phase II trials, the JACCRO CC-08 (n = 36) and CC-09 (n = 25), which evaluated rechallenge chemotherapy with anti-EGFR mAb for KRAS wild-type mCRC. RAS in ctDNA was analyzed at the time points of baseline, 8 weeks, and progression using OncoBEAM RAS CRC kit. RESULTS Sixteen patients were enrolled in this study, with a response rate of 0% and a disease control rate (DCR) of 62.5%. RAS mutations were found at baseline in six patients. The DCR was 33% in patients with RAS mutations in ctDNA, whereas it was 80% in patients without RAS mutation at baseline. Patients with RAS mutation at baseline had significantly shorter progression-free survival (PFS) and overall survival (OS) than those without RAS mutation (median PFS, 2.3 v 4.7 months; hazard ratio [HR], 6.2; P = .013; median OS, 3.8 v 16.0 months; HR, 12.4; P = .0028). Six of 10 patients without RAS mutation at baseline acquired RAS mutations at progression. Postprogression survival after rechallenge treatment was numerically shorter in patients with RAS mutation at progression. CONCLUSION RAS status in ctDNA was significantly associated with clinical outcomes in patients with mCRC receiving rechallenge treatment with anti-EGFR mAb. These findings could support the clinical utility of OncoBEAM RAS CRC kits for anti-EGFR mAb rechallenge in RAS wild-type mCRC.

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True conversions from RAS mutant to RAS wild-type in circulating tumor DNA from metastatic colorectal cancer patients as assessed by methylation and mutational signature

Cancer Letters ◽

10.1016/j.canlet.2021.03.014 ◽

2021 ◽

Author(s):

Chiara Nicolazzo ◽

Ludovic Barault ◽

Salvatore Caponnetto ◽

Gianluigi De Renzi ◽

Francesca Belardinilli ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Cancer Patients ◽

Circulating Tumor Dna ◽

Wild Type ◽

Mutational Signature ◽

Colorectal Cancer Patients ◽

Tumor Dna

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199P Circulating tumor DNA as a dynamic marker for disease burden in patients with metastatic colorectal cancer

Annals of Oncology ◽

10.1016/s0923-7534(21)00357-4 ◽

2016 ◽

Vol 27 ◽

pp. ix62

Author(s):

A. Hsu ◽

H. Hung-Chih ◽

H.-C. Chen ◽

S.-J. Chen

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Disease Burden ◽

Circulating Tumor Dna ◽

Tumor Dna

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Next Generation Sequencing of Circulating Tumor DNA Can Optimize Second Line Treatment in RAS Wild Type Metastatic Colorectal Cancer after Progression on Anti-EGFR Therapy: Time to Rethink Our Approach

Oncology Research and Treatment ◽

10.1159/000521845 ◽

2022 ◽

Author(s):

Davide Mauri ◽

Konstantinos Kamposioras ◽

Dimitris Matthaios ◽

Maria Tolia ◽

Ioanna Nixon ◽

...

Keyword(s):

Colorectal Cancer ◽

Next Generation Sequencing ◽

Metastatic Colorectal Cancer ◽

Circulating Tumor Dna ◽

Clinical Approach ◽

Line Treatment ◽

Next Generation ◽

Wild Type ◽

Tumor Dna ◽

Generation Sequencing

Background Management of Raswild-type colorectal cancer (CRC) patients upon disease progression after the successful use of targeted treatment with anti-EGFR monoclonal antibodies and backbone chemotherapy remains a clinical challenge. Development of treatment resistance with prevalence of pre-existing RAS mutated clones, RAS mutation conversion, truncation of extracellular receptor domains as well as HER2 and MET amplification are molecular events that can be difficult to follow without the use of sophisticated laboratory techniques. Summary The clinical hurdle of re-biopsy and tumor heterogeneity can be overcome by the implementation Next Generation Sequencing (NGS) to analyze circulating tumor DNA (ctDNA) and identify drugable mutations or recovery of RAS-wildness. In this opinion paper we summarize with critical thinking the clinical approach to be followed after the failure of first line treatment in Ras wild-type CRC tumors with the use of NGS. Key Messages Rechallenge with anti-EGFR inhibitors, in case of persistent or recovery of Ras wildness, and targeted approach of specific mutations (BRAF inhibitors) amplifications (anti-Her2 treatment) or fusion proteins (NTRK inhibitors) can by guided by the use of NGS. The use of NGS platforms for serial analysis of ctDNA is an important step to better understand the molecular landscape of metastatic colorectal cancer and guide clinical decisions. NGS should be considered a mainstay in clinical practice for the management of CRC patients and health authorities should consider reimbursing its use in the appropriate clinical settings.

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199P Circulating tumor DNA as a dynamic marker for disease burden in patients with metastatic colorectal cancer

Annals of Oncology ◽

10.1093/annonc/mdw581.032 ◽

2016 ◽

Vol 27 (suppl_9) ◽

Author(s):

A. Hsu ◽

H. Hung-Chih ◽

H-C. Chen ◽

S-J. Chen

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Disease Burden ◽

Circulating Tumor Dna ◽

Tumor Dna

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Faculty Opinions recommendation of Clinical Utility of Analyzing Circulating Tumor DNA in Patients with Metastatic Colorectal Cancer.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.733118524.793553325 ◽

2018 ◽

Author(s):

Kellie Mathis

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Clinical Utility ◽

Circulating Tumor Dna ◽

Tumor Dna

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Small EVs-Associated DNA as Complementary Biomarker to Circulating Tumor DNA in Plasma of Metastatic Colorectal Cancer Patients

Pharmaceuticals ◽

10.3390/ph14020128 ◽

2021 ◽

Vol 14 (2) ◽

pp. 128

Author(s):

Silvia Galbiati ◽

Francesco Damin ◽

Dario Brambilla ◽

Lucia Ferraro ◽

Nadia Soriani ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Cancer Patients ◽

Digital Pcr ◽

Extracellular Vesicle ◽

Circulating Tumor Dna ◽

Mutation Status ◽

Promising Practice ◽

Colorectal Cancer Patients ◽

Tumor Dna

It is widely accepted that assessing circular tumor DNA (ctDNA) in the plasma of cancer patients is a promising practice to evaluate somatic mutations from solid tumors noninvasively. Recently, it was reported that isolation of extracellular vesicles improves the detection of mutant DNA from plasma in metastatic patients; however, no consensus on the presence of dsDNA in exosomes has been reached yet. We analyzed small extracellular vesicle (sEV)-associated DNA of eleven metastatic colorectal cancer (mCRC) patients and compared the results obtained by microarray and droplet digital PCR (ddPCR) to those reported on the ctDNA fraction. We detected the same mutations found in tissue biopsies and ctDNA in all samples but, unexpectedly, in one sample, we found a KRAS mutation that was not identified either in ctDNA or tissue biopsy. Furthermore, to assess the exact location of sEV-associated DNA (outside or inside the vesicle), we treated with DNase I sEVs isolated with three different methodologies. We found that the DNA inside the vesicles is only a small fraction of that surrounding the vesicles. Its amount seems to correlate with the total amount of circulating tumor DNA. The results obtained in our experimental setting suggest that integrating ctDNA and sEV-associated DNA in mCRC patient management could provide a complete real-time assessment of the cancer mutation status.

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