Prognostic value of quantitative ctDNA levels in non small cell lung cancer patients

Prognostic and predictive role of liquid biopsy in lung cancer patients

Introduction

Lung cancer (LC) is a leading cause of cancer-related mortality worldwide. Approximately 80% of LC cases are of the non-small cell lung cancer (NSCLC) type, and approximately two-thirds of these cases are diagnosed in advanced stages. Only systemic treatment methods can be applied to patients in the advanced stages when there is no chance of surgical treatment. Identification of mutations that cause LC is of vital importance in determining appropriate treatment methods. New noninvasive methods are needed to repeat and monitor these molecular analyses. In this regard, liquid biopsy (LB) is the most promising method. This study aimed to determine the effectiveness of LB in detecting EGFR executive gene mutations that cause LC.

Methods

One hundred forty-six patients in stages IIIB and IV diagnosed with non-squamous cell non-small cell LC were included. Liquid biopsy was performed as a routine procedure in cases where no mutation was detected in solid tissue or in cases with progression after targeted therapy. Liquid biopsy samples were also obtained for the second time from 10 patients who showed progression under the applied treatment. Mutation analyses were performed using the Cobas® EGFR Test, a real-time PCR test designed to detect mutations in exons 18, 20, and 21 and changes in exon 19 of the EGFR gene.

Results

Mutation positivity in paraffin blocks was 21.9%, whereas it was 32.2% in LB. Solids and LB were compatible in 16 patients. Additionally, while no mutation was found in solid tissue in the evaluation of 27 cases, it was detected in LB. It has been observed that new mutations can be detected not only at the time of diagnosis, but also in LB samples taken during the follow-up period, leading to the determination of targeted therapy.

Discussion

The results showed that "liquid biopsy" is a successful and alternative non-invasive method for detecting cancer-causing executive mutations, given the limitations of conventional biopsies.

Adding Value to Liquid Biopsy for Brain Tumors: The Role of Imaging

Clinical management in neuro-oncology has changed to an integrative approach that incorporates molecular profiles alongside histopathology and imaging findings. While the World Health Organization (WHO) guideline recommends the genotyping of informative alterations as a routine clinical practice for central nervous system (CNS) tumors, the acquisition of tumor tissue in the CNS is invasive and not always possible. Liquid biopsy is a non-invasive approach that provides the opportunity to capture the complex molecular heterogeneity of the whole tumor through the detection of circulating tumor biomarkers in body fluids, such as blood or cerebrospinal fluid (CSF). Despite all of the advantages, the low abundance of tumor-derived biomarkers, particularly in CNS tumors, as well as their short half-life has limited the application of liquid biopsy in clinical practice. Thus, it is crucial to identify the factors associated with the presence of these biomarkers and explore possible strategies that can increase the shedding of these tumoral components into biological fluids. In this review, we first describe the clinical applications of liquid biopsy in CNS tumors, including its roles in the early detection of recurrence and monitoring of treatment response. We then discuss the utilization of imaging in identifying the factors that affect the detection of circulating biomarkers as well as how image-guided interventions such as focused ultrasound can help enhance the presence of tumor biomarkers through blood-brain barrier (BBB) disruption.

Detecting ALK, ROS1, and RET fusions and the METΔex14 splicing variant in liquid biopsies of non-small-cell lung cancer patients using RNA-based techniques

ALK, ROS1, and RET fusions and MET∆ex14 variant associate with response to targeted therapies in non-small-cell lung cancer (NSCLC). Technologies for fusion testing in tissue must be adapted to liquid biopsies, which are often the only material available. In this study, circulating-free RNA (cfRNA) and extracellular vesicle RNA (EV-RNA) were purified from liquid biopsies. Fusion and MET∆ex14 transcripts were analyzed by nCounter (Nanostring) and digital PCR (dPCR) using the QuantStudio® System (Applied Biosystems). We found that nCounter detected ALK, ROS1, RET, or MET∆ex14 aberrant transcripts in 28/40 cfRNA samples from positive patients and 0/16 of control individuals (70% sensitivity). Regarding dPCR, aberrant transcripts were detected in the cfRNA of 25/40 positive patients. Concordance between the two techniques was 58%. Inferior results were obtained when analyzing EV-RNA, where nCounter often failed due to a low amount of input RNA. Finally, results of dPCR testing in serial liquid biopsies of five patients correlated with response to targeted therapy. We conclude that nCounter can be used for multiplex detection of fusion and MET∆ex14 transcripts in liquid biopsies, showing a performance comparable with next-generation sequencing platforms. dPCR could be employed for disease follow-up in patients with a known alteration. cfRNA should be preferred over EV-RNA for these analyses.

Monitoring with circulating tumor cells in the perioperative setting of patients with surgically treated stages I-IIIA NSCLC

Background

Surgery is regarded as the treatment's cornerstone for early stage and locally advanced non-small cell lung cancer (NSCLC) whenever the tumor is considered resectable. Liquid biopsy is one of the most promising research areas in oncology in the last 10 years, providing a useful non-invasive tool to detect and monitor cancer. The prognostic value of circulating tumor cells (CTCs) has been studied in different cancer types and had been related with a higher risk of relapse and worse prognosis. The aim of this study is to evaluate the prognostic value of CTC detection in patients with stage I-IIIA NSCLC treated with surgery.

Methods

We conducted a prospective, single-center study of 180 consecutive patients with resected and pathological confirmed stage I to IIIA (TNM AJCC/UICC 8th edition) NSCLC. Patients' blood samples were processed and CTCs were characterized before and after the surgery. A cohort of patients had CTC determination after chemotherapy and surgery. Cut-off points were established in 1 and 5 CTCs for statistical analysis.

Results

A proportion of 76.7% had at least 1 CTC before the surgery, and 30.6% had 5 or more, while 55.9% had at least 1 CTC after surgery, and 8.3% had 5 or more. We found no correlation between preoperative CTC detection for a cut-off of 5 with neither overall survival (OS) [hazard ratio (HR): 0.99, P=0.887], disease-free survival (DFS) (HR: 0.95, P=0.39) nor relapse (32.7% vs. 28.8%, P=0.596). We also did not find a correlation between postoperative CTCs detection for a cut-off of 5 with either OS (HR: 1.01, P=0.808), DFS (HR: 0.95, P=0.952) or relapse (26.7% vs. 29.5%, P=0.83). The mean change in the number of CTCs over time between preoperative and postoperative samples was 2.13, with a standard deviation of 6.78.

Conclusions

Despite the large cohort of patients included in this study, CTC monitoring in the perioperative setting was not correlated with relapse, DFS or OS in our study, and therefore cannot be recommended as a reliable biomarker for minimal residual disease (MRD) after surgery.

Liquid Biopsy for Lung Cancer: Up-to-Date and Perspectives for Screening Programs

Lung cancer is the deadliest cancer worldwide. Tissue biopsy is currently employed for the diagnosis and molecular stratification of lung cancer. Liquid biopsy is a minimally invasive approach to determine biomarkers from body fluids, such as blood, urine, sputum, and saliva. Tumor cells release cfDNA, ctDNA, exosomes, miRNAs, circRNAs, CTCs, and DNA methylated fragments, among others, which can be successfully used as biomarkers for diagnosis, prognosis, and prediction of treatment response. Predictive biomarkers are well-established for managing lung cancer, and liquid biopsy options have emerged in the last few years. Currently, detecting EGFR p.(Tyr790Met) mutation in plasma samples from lung cancer patients has been used for predicting response and monitoring tyrosine kinase inhibitors (TKi)-treated patients with lung cancer. In addition, many efforts continue to bring more sensitive technologies to improve the detection of clinically relevant biomarkers for lung cancer. Moreover, liquid biopsy can dramatically decrease the turnaround time for laboratory reports, accelerating the beginning of treatment and improving the overall survival of lung cancer patients. Herein, we summarized all available and emerging approaches of liquid biopsy-techniques, molecules, and sample type-for lung cancer.

Molecular Divergence upon EGFR-TKI Resistance Could Be Dependent on the Exon Location of the Original EGFR-Sensitizing Mutation

Tumor molecular profiling upon disease progression enables investigations of the tumor evolution. Next-generation sequencing (NGS) of liquid biopsies constitutes a noninvasive readily available source of tumor molecular information. In this study, 124 plasma samples from advanced EGFR-positive NSCLC patients, treated with a first-line EGFR tyrosine kinase inhibitor (EGFR-TKI) were collected upon disease progression. The circulating cell-free DNA (cfDNA) was sequenced using the Oncomine Pan-Cancer Cell-Free Assay™. Excluding EGFR mutations, the most frequently mutated gene was TP53 (57.3%), followed by APC (11.3%), FGFR3 (7.3%), and KRAS (5.6%). Different molecular alterations were observed upon disease progression depending on the location of the original EGFR-sensitizing mutation. Specifically, the detection of the p.T790M mutation was significantly associated with the presence of exon 19 mutations in EGFR (Fisher p-value: 0.028). All KRAS activating mutations (n = 8) were detected in tumors with EGFR mutations in exons 18 and 21 (Fisher p-value < 0.001). Similarly, mutations in NRAS and HRAS were more frequently detected in samples from tumors harboring mutations in exons 18 or 21 (Fisher p-value: 0.050 and Fisher p-value: 0.099, respectively). In conclusion, our data suggest that the mechanisms underlying EGFR-TKI resistance could be dependent on the exon location of the original EGFR-sensitizing mutation.

Circulating Tumor DNA as a Cancer Biomarker: An Overview of Biological Features and Factors That may Impact on ctDNA Analysis

Cancer cells release nucleic acids, freely or associated with other structures such as vesicles into body fluids, including blood. Among these nucleic acids, circulating tumor DNA (ctDNA) has emerged as a minimally invasive biomarker for tumor molecular profiling. However, certain biological characteristics of ctDNA are still unknown. Here, we provide an overview of the current knowledge about ctDNA biological features, including size and structure as well as the mechanisms of ctDNA shedding and clearance, and the physio-pathological factors that determine ctDNA levels. A better understanding of ctDNA biology is essential for the development of new methods that enable the analysis of ctDNA.

Treatment Sequencing in Resectable Lung Cancer: The Good and the Bad of Adjuvant Versus Neoadjuvant Therapy

The treatment scenario for patients with resectable non-small cell lung cancer has changed dramatically with the incorporation of immunotherapy. The introduction of immunotherapy into treatment algorithms has yielded improved clinical outcomes in several phase II and III trials in both adjuvant (Impower010 and PEARLS) and neoadjuvant settings (JHU/MSK, LCMC3, NEOSTAR, Columbia/MGH, NADIM, and CheckMate-816), leading to new U.S. Food and Drug Administration approvals in this sense. Different treatment options are now available for patients, making the optimal treatment scenario a matter of intense debate. In this review, we summarize the main results concerning treatment sequencing in resectable non-small cell lung cancer from the past 30 years in the preimmunotherapy era, focusing on recent advances after incorporation of immunotherapy. Finally, the utility of several parameters (PD-L1, tumor mutational burden, radiomics, circulating tumor DNA, T-cell receptor, and immune populations) as predictive biomarkers for therapy personalization is discussed.

Simultaneous monitoring of disease and microbe dynamics through plasma DNA sequencing in pediatric patients with acute lymphoblastic leukemia

Treatment of acute lymphoblastic leukemia (ALL) necessitates continuous risk assessment of leukemic disease burden and infections that arise in the setting of immunosuppression. This study was performed to assess the feasibility of a hybrid capture next-generation sequencing panel to longitudinally measure molecular leukemic disease clearance and microbial species abundance in 20 pediatric patients with ALL throughout induction chemotherapy. This proof of concept helps establish a technical and conceptual framework that we anticipate will be expanded and applied to additional patients with leukemia, as well as extended to additional cancer types. Molecular monitoring can help accelerate the attainment of insights into the temporal biology of host-microbe-leukemia interactions, including how those changes correlate with and alter anticancer therapy efficacy. We also anticipate that fewer invasive bone marrow examinations will be required, as these methods improve with standardization and are validated for clinical use.

EGFR-dependent mechanisms of resistance to osimertinib determined by ctDNA NGS analysis identify patients with better outcome

Background

Osimertinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that is highly selective for EGFR^T790M subclones in patients with EGFR^sensitizing non-small cell lung cancer (NSCLC). Unfortunately, all patients develop resistance through EGFR-dependent or EGFR-independent pathways. Recently, circulating tumoral DNA (ctDNA) analysis has highlighted the usefulness of plasma genotyping for exploring patient survival outcomes after disease progression under osimertinib.

Methods

Plasma samples from patients treated with osimertinib as a second-line therapy were collected and the presence of molecular alterations of acquired resistance was evaluated after relapse under osimertinib using ctDNA molecular profiling by next-generation sequencing (NGS) assays. The clinical implications of these genomic alterations for the efficiency of the third-generation TKI were further assessed.

Results

Our ctDNA molecular profiling of plasma samples highlighted large number of actionable genomic alterations. According to ctDNA NGS results, patients were classified as having developed an EGFR-dependent or EGFR-independent mechanism of resistance. Thus, patients who developed an EGFR-dependent mechanism of resistance responded longer to osimertinib (13.8 vs. 4.6 months; P<10⁻⁴) and have a better post-osimertinib clinical outcome than EGFR-independent resistant patients. Moreover, the development of an EGFR-dependent mechanism of osimertinib resistance was identified as the best fit to determine patients’ clinical outcome compared with EGFR^T790M status alone (P=0.003).

Conclusions

Our study highlights the potential of ctDNA NGS to rapidly select the appropriate drug after osimertinib failure and to determine clinical outcomes of patients. We suggest that ctDNA NGS should be more intensively used in clinical practice to follow patients under third-generation TKIs.

R-Score: A New Parameter to Assess the Quality of Variants' Calls Assessed by NGS Using Liquid Biopsies

Next-generation sequencing (NGS) has enabled a deeper knowledge of the molecular landscape in non-small cell lung cancer (NSCLC), identifying a growing number of targetable molecular alterations in key genes. However, NGS profiling of liquid biopsies risk for false positive and false negative calls and parameters assessing the quality of NGS calls remains lacking. In this study, we have evaluated the positive percent agreement (PPA) between NGS and digital PCR calls when assessing EGFR mutation status using 85 plasma samples from 82 EGFR-positive NSCLC patients. According to our data, variant allele fraction (VAF) was significantly lower in discordant calls and the median of the absolute values of all pairwise differences (MAPD) was significantly higher in discordant calls (p < 0.001 in both cases). Based on these results, we propose a new parameter that integrates both variables, named R-score. Next, we sought to evaluate the PPA for EGFR mutation calls between two independent NGS platforms using a subset of 40 samples from the same cohort. Remarkably, there was a significant linear correlation between the PPA and the R-score (r = 0.97; p < 0.001). Specifically, the PPA of samples with an R-score ≤ -1.25 was 95.83%, whereas PPA falls to 81.63% in samples with R-score ≤ 0.25. In conclusion, R-score significantly correlates with PPA and can assist laboratory medicine specialists and data scientists to select reliable variants detected by NGS.

Use of Liquid Biopsy in the Care of Patients with Non-Small Cell Lung Cancer

OPINION STATEMENT

Recent technological advances have enabled the development of liquid biopsy-based approaches, which have revolutionized the diagnostic world. The analysis of circulating tumor DNA (ctDNA) has several clinical applications. First, ctDNA genotyping is becoming widely used for non-invasive biomarker testing. Of note, in lung cancer patients in whom biopsies are difficult to obtain, ctDNA has led to significant improvement in the diagnosis and identification of therapeutic targets. In addition, ctDNA quantification over the course of the disease can be useful for tumor response to treatment monitoring and for early detection of resistance mutations. ctDNA levels per se are also of prognostic significance and could be used to tailor treatments. Finally, improvements in assay sensitivity are facilitating the development of liquid biopsy-based tests for the detection of ctDNA at very low allele frequencies (AFs), which can be used for the measurement of minimal residual disease and ultimately for the development of strategies (by complementing imaging techniques) aimed to improve the efficiency of lung cancer screening programs.

LungBEAM: A prospective multicenter study to monitor stage IV NSCLC patients with EGFR mutations using BEAMing technology

OBJECTIVES

The aim of LungBEAM was to determine the value of a novel epidermal growth factor receptor (EGFR) mutation test in blood based on BEAMing technology to predict disease progression in advanced non-small cell lung cancer (NSCLC) patients treated with first- or second-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Another goal was to monitor the dynamics of EGFR mutations, as well as to track EGFR exon 20 p.T790M (p.T790M) resistance during treatment, as critical indicators of therapeutic efficacy and patient survival.

METHODS

Stage IV NSCLC patients with locally confirmed EGFR-TKI sensitizing mutations (ex19del and/or L858R) in biopsy tissue who were candidates to receive first- or second-generation EGFR-TKI as first-line therapy were included. Plasma samples were obtained at baseline and every 4 weeks during treatment until a progression-free survival (PFS) event or until study completion (72-week follow-up). The mutant allele fraction (MAF) was determined for each identified mutation using BEAMing.

RESULTS

A total of 68 of the 110 (61.8%) patients experienced a PFS event. Twenty-six patients (23.6%) presented with an emergent p.T790M mutation in plasma at some point during follow-up, preceding radiologic progression with a median of 76 (interquartile ratio: 54-111) days. Disease progression correlated with the appearance of p.T790M in plasma with a hazard ratio (HR) of 1.94 (95% confidence interval [CI], 1.48-2.54; p < 0.001). The HR for progression in patients showing increasing plasma sensitizing mutation levels (positive MAF slope) versus patients showing either decreasing or unchanged plasma mutation levels (negative or null MAF slopes) was 3.85 (95% CI, 2.01-7.36; p < 0.001).

CONCLUSION

Detection and quantification of EGFR mutations in circulating tumor DNA using the highly sensitive BEAMing method should greatly assist in optimizing treatment decisions for advanced NSCLC patients.

Combining liquid biopsy and radiomics for personalized treatment of lung cancer patients. State of the art and new perspectives

Lung cancer has become a paradigm for precision medicine in oncology, and liquid biopsy (LB) together with radiomics may have a great potential in this scenario. They are both minimally invasive, easy to perform, and can be repeated during patient's follow-up. Also, increasing evidence suggest that LB and radiomics may provide an efficient way to screen and diagnose tumors at an early stage, including the monitoring of any change in the tumor molecular profile. This could allow treatment optimization, improvement of patients' quality of life, and healthcare-related costs reduction. Latest reports on lung cancer patients suggest a combination of these two strategies, along with cutting-edge data analysis, to decode valuable information regarding tumor type, aggressiveness, progression, and response to treatment. The approach seems more compatible with clinical practice than the current standard, and provides new diagnostic companions being able to suggest the best treatment strategy compared to conventional methods. To implement radiomics and liquid biopsy directly into clinical practice, an artificial intelligence (AI)-based system could help to link patients' clinical data together with tumor molecular profiles and imaging characteristics. AI could also solve problems and limitations related to LB and radiomics methodologies. Further work is needed, including new health policies and the access to large amounts of high-quality and well-organized data, allowing a complementary and synergistic combination of LB and imaging, to provide an attractive choice e in the personalized treatment of lung cancer.

Analysis of circulating tumour DNA to identify patients with epidermal growth factor receptor-positive non-small cell lung cancer who might benefit from sequential tyrosine kinase inhibitor treatment

BACKGROUND

Survival data support the use of first-line osimertinib as the standard of care for epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC). However, it remains unclear whether upfront osimertinib is superior to sequential first- or second-generation tyrosine kinase inhibitors (TKIs) followed by osimertinib for all patients. It is impossible to predict which patients are at high risk of progression, and this constitutes a major limitation of the sequential TKI approach.

PATIENTS AND METHODS

A total of 830 plasma samples from 228 patients with stage IV, EGFR-positive NSCLC who were treated with first-line TKIs were analysed by digital polymerase chain reaction (dPCR).

RESULTS

The circulating tumour DNA (ctDNA) levels helped to identify patients with significantly improved survival rate, regardless of the treatment. Patients treated with first- or second-generation TKIs (N = 189) with EGFR mutations in plasma at a mutant allele frequency (MAF) <7% before treatment initiation (low-risk patients) or who were ctDNA negative after 3 or 6 months of treatment and with an MAF <7% at diagnosis (high responders) had two-thirds lower risk of death than patients in the opposite situation (adjusted hazard ratio [HR] = 0.38; 95% confidence interval [CI]: 0.23-0.64 and HR = 0.22; 95% CI: 0.12-0.42, respectively). The median overall survival (OS) for low-risk patients and high responders treated with first- or second-generation TKIs was 34.2 months and not reached, respectively, regardless of second-line treatment. There were no significant difference in OS between low-risk or high-responder patients treated upfront with osimertinib (N = 39) and those treated under a sequential approach with osimertinib (N = 60). Median OS was not reached in both cases.

CONCLUSIONS

Pre-treatment ctDNA levels identify low-risk patients, who may benefit from sequential TKI treatment. Information regarding EGFR mutation clearance can help to improve patient selection.

Next-generation sequencing for tumor mutation quantification using liquid biopsies

Background Non-small cell lung cancer (NSCLC) patients benefit from targeted therapies both in first- and second-line treatment. Nevertheless, molecular profiling of lung cancer tumors after first disease progression is seldom performed. The analysis of circulating tumor DNA (ctDNA) enables not only non-invasive biomarker testing but also monitoring tumor response to treatment. Digital PCR (dPCR), although a robust approach, only enables the analysis of a limited number of mutations. Next-generation sequencing (NGS), on the other hand, enables the analysis of significantly greater numbers of mutations. Methods A total of 54 circulating free DNA (cfDNA) samples from 52 NSCLC patients and two healthy donors were analyzed by NGS using the Oncomine™ Lung cfDNA Assay kit and dPCR. Results Lin's concordance correlation coefficient and Pearson's correlation coefficient between mutant allele frequencies (MAFs) assessed by NGS and dPCR revealed a positive and linear relationship between the two data sets (ρc = 0.986; 95% confidence interval [CI] = 0.975-0.991; r = 0.987; p < 0.0001, respectively), indicating an excellent concordance between both measurements. Similarly, the agreement between NGS and dPCR for the detection of the resistance mutation p.T790M was almost perfect (K = 0.81; 95% CI = 0.62-0.99), with an excellent correlation in terms of MAFs (ρc = 0.991; 95% CI = 0.981-0.992 and Pearson's r = 0.998; p < 0.0001). Importantly, cfDNA sequencing was successful using as low as 10 ng cfDNA input. Conclusions MAFs assessed by NGS were highly correlated with MAFs assessed by dPCR, demonstrating that NGS is a robust technique for ctDNA quantification using clinical samples, thereby allowing for dynamic genomic surveillance in the era of precision medicine.

ctDNA from body fluids is an adequate source for EGFR biomarker testing in advanced lung adenocarcinoma

OBJECTIVES

Epidermal growth factor receptor (EGFR) biomarker testing using blood-based liquid biopsies remains challenging due to the low concentration of circulating tumor DNA (ctDNA) in certain plasma samples. The aim of this study is to evaluate the usefulness for EGFR biomarker testing of ctDNA from pleural effusions, cerebrospinal fluids, ascites and pericardial effusions obtained during the clinical management of lung adenocarcinoma patients.

METHODS

For comparison purposes, 23 paired plasma and body fluid samples were collected from 17 patients with EGFR-positive lung adenocarcinoma. After circulating free DNA (cfDNA) isolation, samples were evaluated for the initial EGFR-sensitizing mutation and the p.T790M resistance mutation by array-based digital PCR (dPCR).

RESULTS

Body fluids had more cfDNA than plasma samples (1.90 vs. 0.36 ng/µL; p=0.0130), and more samples tested positive for EGFR mutations (21 vs. 16 samples), with a total of 28 vs. 22 variants detected. Furthermore, mutant allele frequencies (MAFs) observed in body fluids were significantly higher than those assessed in the paired plasma samples for EGFR-sensitizing mutations (median MAFs = 15.8 vs. 0.8%; p=0.0004) as well as for the p.T790M resistance mutation (median MAFs = 8.69 vs. 0.16%; p=0.0390). Importantly, two patients who had progressed on first-generation EGFR-tyrosine kinase inhibitors with a dubious result for p.T790M plasma (MAFs = 0.11%) had an indisputably positive result in their respective body fluid samples (MAFs = 10.25 and 9.66%).

CONCLUSIONS

ctDNA derived from body fluids is an informative source for EGFR biomarker testing, with greater sensitivity than plasma samples.

Molecular characterization of advanced non-small cell lung cancer patients by cfDNA analysis: experience from routine laboratory practice

BACKGROUND

Analysis of circulating free DNA (cfDNA) by the real-time PCR cobas® EGFR Mutation Test v2 (cobas® EGFR Test) is a diagnostic approach used in clinical practice for the characterization of advanced non-small cell lung cancer (NSCLC) patients. The test additionally outputs a semiquantitative index (SQI) which reflects the proportion of mutated versus wild-type copies of the EGFR gene in cfDNA with potential use as a biomarker. CfDNA concentration and cfDNA fragmentation pattern have also shown potential utility as biomarkers for cancer patients. We evaluated the implementation of EGFR testing and cfDNA related parameters in NSCLC patients in routine clinical setting as biomarkers for disease stage and diagnosis.

METHODS

A prospective cohort of 173 locally advanced or metastatic NSCLC TKI-naïve patients analyzed by the cobas® EGFR Test were included in the study. Reproducibility of the test was assessed in 56 patients. The concentration of cfDNA and fragment size pattern was measured using fluorometry and microchip electrophoresis respectively.

RESULTS

The test showed high diagnostic accuracy when compared to the gold standard of biopsy tumor tissue testing. The SQI value showed a moderate reproducibility (r2=0.70) and did not correlate with cfDNA concentration (r2=0.17, P=0.28) or disease stage (stage III patients SQI =9.1±3.1 and stage IV patients SQI =11.5±4.8, P=0.41). We found differences in SQI values according to the type of EGFR mutation (Ex19Del mutations, SQI =13.6; p.L858R, SQI =8.88; P=0.001). Stage IV patients had higher concentrations of cfDNA (P<0.0001) and higher fractions of cfDNA 100-250 base pairs (bp) fragments (P=0.01) compared to stage III patients. From the ROC curve analysis, cfDNA concentration showed higher AUC compared to cfDNA 100-250 bp fragments (0.86 vs. 0.71). We obtained a cut-off value for cfDNA concentration of 20.3 ng/mL with 72.3% sensitivity and 95% specificity for predicting disease stage in TKI-naïve advanced NSCLC patients.

CONCLUSIONS

The study indicates that cfDNA analysis in plasma for EGFR testing by RT-PCR is an accurate and fast method to initially stratify NSCLC patients in a real-world clinical setting. However, the SQI has limited clinical value. The cfDNA concentration and fragmentation pattern have clear potential clinical utility for tumor staging in NSCLC patients.

Comprehensive cross-platform comparison of methods for non-invasive EGFR mutation testing: results of the RING observational trial

Several platforms for noninvasive EGFR testing are currently used in the clinical setting with sensitivities ranging from 30% to 100%. Prospective studies evaluating agreement and sources for discordant results remain lacking. Herein, seven methodologies including two next‐generation sequencing (NGS)‐based methods, three high‐sensitivity PCR‐based platforms, and two FDA‐approved methods were compared using 72 plasma samples, from EGFR‐mutant non‐small‐cell lung cancer (NSCLC) patients progressing on a first‐line tyrosine kinase inhibitor (TKI). NGS platforms as well as high‐sensitivity PCR‐based methodologies showed excellent agreement for EGFR‐sensitizing mutations (K = 0.80–0.89) and substantial agreement for T790M testing (K = 0.77 and 0.68, respectively). Mutant allele frequencies (MAFs) obtained by different quantitative methods showed an excellent reproducibility (intraclass correlation coefficients 0.86–0.98). Among other technical factors, discordant calls mostly occurred at mutant allele frequencies (MAFs) ≤ 0.5%. Agreement significantly improved when discarding samples with MAF ≤ 0.5%. EGFR mutations were detected at significantly lower MAFs in patients with brain metastases, suggesting that these patients risk for a false‐positive result. Our results support the use of liquid biopsies for noninvasive EGFR testing and highlight the need to systematically report MAFs.

ctDNA analysis reveals different molecular patterns upon disease progression in patients treated with osimertinib

Background

Several clinical trials have demonstrated the efficacy and safety of osimertinib in advanced non-small-cell lung cancer (NSCLC). However, there is significant unexplained variability in treatment outcome.

Methods

Observational prospective cohort of 22 pre-treated patients with stage IV NSCLC harboring the epidermal growth factor receptor (EGFR) p.T790M resistance mutation and who were treated with osimertinib. Three hundred and twenty-six serial plasma samples were collected and analyzed by digital PCR (dPCR) and next-generation sequencing (NGS).

Results

The median progression-free survival (PFS), since the start of osimertinib, was 8.9 [interquartile range (IQR): 4.6–18.0] months. The median treatment durations of sequential gefitinib + osimertinib, afatinib + osimertinib and erlotinib + osimertinib treatments were 30.1, 24.6 and 21.1 months, respectively. The p.T790M mutation was detected in 19 (86%) pre-treatment blood samples. Undetectable levels of the original EGFR-sensitizing mutation after 3 months of treatment were associated with superior PFS (HR: 0.2, 95% CI: 0.05–0.7). Likewise, re-emergence of the original EGFR mutation, alone or together with the p.T790M mutation was significantly associated with shorter PFS (HR: 8.8, 95% CI: 1.1–70.7 and HR: 5.9, 95% CI: 1.2–27.9, respectively). Blood-based monitoring revealed three molecular patterns upon progression to osimertinib: sensitizing+/T790M+/C797S+, sensitizing+/T790M+/C797S–, and sensitizing+/T790M–/C797S–. Median time to progression in patients showing the triplet pattern (sensitizing+/T790M+/C797S+) was 12.27 months compared with 4.87 months in patients in whom only the original EGFR sensitizing was detected, and 2.17 months in patients showing the duplet pattern (sensitizing+/T790M+). Finally, we found that mutations in exon 545 of the PIK3CA gene were the most frequent alteration detected upon disease progression in patients without acquired EGFR-resistance mutations.

Conclusions

Different molecular patterns identified by plasma genotyping may be of prognostic significance, suggesting that the use of liquid biopsy is a valuable approach for tumor monitoring.

Next-generation sequencing to dynamically detect mechanisms of resistance to ALK inhibitors in ALK-positive NSCLC patients: a case report

Tyrosine kinase inhibitors (TKIs) of the anaplastic lymphoma kinase gene (ALK) have significantly improved the quality of life and survival of non-small cell lung cancer (NSCLC) patients whose tumors harbor an ALK translocation. However, most of these patients relapse within 2 to 3 years as the tumor acquires resistance mutations. Unlike beaming and digital PCR (dPCR), which only allow a few mutations to be analyzed, next-generation sequencing (NGS) approaches enable the simultaneous screening of multiple genetic alterations even when the frequencies of the variants are very low. We present the case of a 52-year-old man who was diagnosed with an ALK-positive NSCLC and was treated with crizotinib and, subsequently, ceritinib. The analysis of serial liquid biopsies by NGS detected two asynchronous mutations arising in the ALK locus during disease progression, namely p.Gly1269Ala (c.3806G>C) and p.Gly1202Arg (c.3604G>A), that conferred resistance to crizotinib and ceritinib, respectively. The resistance mutations were detected independently at different times, and could be imputed to different metastatic lesions, thereby highlighting the importance of heterogeneity in advance disease. Plasma levels of ALK resistance mutations correlated well with tumor responses assessed by CT scans and bone scintigraphy, demonstrating that non-invasive tumor molecular profiling by NGS allows the efficient dynamic monitoring of ALK-positive NSCLC patients, and outperforms dPCR and beaming because more somatic mutations can be tracked over the course of the treatment. In conclusion, this case report illustrates the usefulness NGS to guide therapeutic decisions in ALK-positive NSCLC patients based tumor molecular profile upon disease progression.

Clinical utility of liquid biopsy for the diagnosis and monitoring of EML4-ALK NSCLC patients

Background

Genomic rearrangement in anaplastic lymphoma kinase (ALK) gene occurs in 3-7% of patients with non-small-cell lung cancer (NSCLC). The detection of this alteration is crucial as ALK positive NSCLC patients benefit from ALK inhibitors, which improve both the patient's quality of life and overall survival (OS) compared to traditional chemotherapy.

Content

In routine clinical practice, ALK rearrangements are detected using tissue biopsy. Nevertheless, the availability of tumor tissue is compromised in NSCLC patients due to surgical complications or difficult access to the cancer lesion. In addition, DNA quality and heterogeneity may impair tumor biopsies testing. These limitations can be overcome by liquid biopsy, which refers to non-invasive approaches for tumor molecular profiling. In this paper we review currently available technology for non-invasive ALK testing, in NSCLC patients, based on the analysis of circulating tumor DNA (ctDNA), circulating tumor RNA (ctRNA), circulating tumor cells (CTCs), tumor-educated platelets (TEPs) and extracellular vesicles (EVs) such as exosomes.

Summary and outlook

Non-invasive tumor molecular profiling is crucial to improve outcomes and quality of life of NSCLC patients whose tumors harbor a translocation involving ALK locus.

The Value of Next-Generation Sequencing for Treatment in Non-Small Cell Lung Cancer Patients: The Observational, Real-World Evidence in China

Background

Great success has been made in the targeting therapy of advanced non-small cell lung cancer (NSCLC). Nowadays, next generation sequencing (NGS) is acquirable and affordable in developed area of China. Using this feasible and accurate method of detecting therapeutic genes would help to select optimal treatments to extend patients survival. Here, we identified somatic mutations by NGS and analyzed the value for treatment of NSCLC in a real-world clinical setting.

Methods

NGS was carried out on biopsy samples obtained from 66 advanced unresectable NSCLC patients who had not received any treatment. 23 patients received liquid biopsy after failure of first-line targeted treatment. The mutation profiling as well as associations between mutations and clinicopathological characters was analyzed. The study also assessed the values of NGS for choosing treatment options and predicting prognosis in NSCLC patients.

Results

152 somatic mutations were identified in 45 (68.18%) tissue samples. The most frequently mutated genes were EGFR (42.42%), TP53 (31.82%) and KRAS (15.15%). Specifically, the most frequent EGFR (42.42%), EGFR (42.42%), p = 0.046). In addition, in the smoking group, patients with EGFR (42.42%), p = 0.046). In addition, in the smoking group, patients with EGFR (42.42%), EGFR (42.42%), p = 0.046). In addition, in the smoking group, patients with

Conclusions

The observational study from real-world demonstrated that using NGS in routine clinical detection may be useful in guiding the therapy decisions and benefit more Chinese NSCLC patients.

The Value of Liquid Biopsies for Guiding Therapy Decisions in Non-small Cell Lung Cancer

Targeted therapies have allowed for an individualized treatment approach in non-small-cell lung cancer (NSCLC). The initial therapeutic decisions and success of targeted therapy depend on genetic identification of personal tumor profiles. Tissue biopsy is the gold standard for molecular analysis, but non-invasive or minimally invasive liquid biopsy methods are also now used in clinical practice, allowing for later monitoring and optimization of the cancer treatment. The inclusion of liquid biopsy in the management of NSCLC provides strong evidence on early treatment response, which becomes a basis for determining disease progression and the need for changes in treatment. Liquid biopsies can drive the decision making for treatment strategies to achieve better patient outcomes. Cell-free DNA and circulating tumor cells obtained from the blood are promising markers for determining patient status. They may improve cancer treatments, allow for better treatment control, enable early interventions, and change decision making from reactive actions toward more predictive early interventions. This review aimed to present current knowledge on and the usefulness of liquid biopsy studies in NSCLC from the perspective of how it has allowed individualized treatments according to gene profiling and how the method may alter the treatment decisions in the future.

Mixed response to osimertinib and the beneficial effects of additional local therapy

BACKGROUND

Although non-small cell lung cancers (NSCLCs) harboring EGFR mutations initially respond well to EGFR-tyrosine kinase inhibitors (TKIs), they typically progress after approximately one year. The EGFR T790M mutation is the most common resistance mechanism. NSCLCs with T790M respond well to osimertinib; however, the heterogeneity of NSCLCs may limit the efficacy. Some patients exhibit a mixed response (MR), in which some lesions shrink and others progress, but little is known of the incidence and characteristics of such a response. We sought to determine the frequency and clinical course in MR patients.

METHODS

We retrospectively reviewed the records of patients who had received osimertinib for NSCLC with EGFR T790M.

RESULTS

Between April and December 2016, 48 patients were administered osimertinib. Seven patients (15%) exhibited one of two MR types: (i) progressive lesions that did not include the re-biopsy site (5 patients), and (ii) progressive lesions that included the re-biopsy site (2 patients). The most frequent progressive sites were liver and lung metastases (4 patients). Three patients continued osimertinib following an MR, one of whom had received local therapy for liver metastasis and achieved disease control on osimertinib for an additional four months.

CONCLUSION

An MR was detected in 15% of NSCLC patients with T790M. This finding suggests that several different resistance mechanisms are active within a single patient who develops resistance to EGFR-TKIs. Osimertinib is basically effective for tumors that acquire resistance to EGFR-TKIs as a result of T790M mutation. Therefore, additional local therapy may be beneficial for patients who develop an MR to osimertinib.

Current and Future Molecular Testing in NSCLC, What Can We Expect from New Sequencing Technologies?

Recent changes in lung cancer care, including new approvals in first line and the introduction of high-throughput molecular technologies in routine testing led us to question ourselves on how deeper molecular testing may be helpful for the optimal use of targeted drugs. In this article, we review recent results in the scope of personalized medicine in lung cancer. We discuss biomarkers that have a therapeutic predictive value in lung cancer with a focus on recent changes and on the clinical value of large scale sequencing strategies. We review the use of second- and third-generation EGFR and ALK inhibitors with a focus on secondary resistance alterations. We discuss anti-BRAF and anti-MEK combo, emerging biomarkers as NRG1 and NTRKs fusions and immunotherapy. Finally, we discuss the different technical issues of comprehensive molecular profiling and show how large screenings might refine the prediction value of individual markers. Based on a review of recent publications (2012⁻2018), we address promising approaches for the treatment of patients with lung cancers and the technical challenges associated with the identification of new predictive markers.