Peripheral blood for epidermal growth factor receptor mutation detection in non-small cell lung cancer patients

A meta-analysis of liquid biopsy versus tumor histology for detecting EGFR mutations in non-small cell lung cancer

OBJECTIVE

To assess the consistency of liquid biopsy and histologic analysis for detecting epidermal growth factor receptor (EGFR) gene mutations in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

The PubMed, Cochrane Library, and CNKI et al. databases were searched to collect studies comparing liquid biopsy and histopathologic specimens. The EGFR mutation status was extracted from the studies, and meta-analysis was carried out using Stata 12.0 software.

RESULTS

We included 22 studies of 3359 NSCLC patients. In the meta-analysis, eight papers with a sample size of size <150 had an OR of 45, indicating that liquid biopsy had high sensitivity for detecting EGFR mutations. In addition, seven papers with a sample size ≥150, with an OR of 70, reported that liquid biopsy was highly susceptible to detecting EGFR mutations. The pooled diagnostic effect size of 6 for literature that included the T790M mutation was smaller than that of 69 for literature that did not include the T790M mutation, and I2 >50 %, showing that literature that did not include the T790M mutation was more heterogeneous. The combined diagnostic effect size of 34 in the exon 19 group was smaller than that in the group with no exon 19, with an I2>50 %. There was substantial heterogeneity in both the exon 19 group and the non-exon 19 group. The group with the L858R mutation had a greater diagnostic effect size of 28, lower I2, and less heterogeneity than the group without the L858R mutation. The exon 21 group had a larger pooled diagnostic effect size of 66, a smaller I2, and less heterogeneity than the group without exon 21.

CONCLUSION

Liquid biopsy and histologic analysis have high concordance for detecting EGFR mutations in NSCLC. Liquid biopsy can provide an alternative technology for individualized treatment and monitoring of minimal residual disease (MRD) in advanced NSCLC patients with EGFR tyrosine kinase inhibitor-sensitive and drug resistance (T790M) mutations.

Comprehensive analysis of clinicopathological profiles in adenosquamous carcinoma of the lung

OBJECTIVES

Adenosquamous carcinoma (ASC), an uncommon subtype within non-small cell lung cancer (NSCLC), manifests distinctive traits of aggressiveness, embodying a fusion of both adenocarcinoma (AC) and squamous cell carcinoma (SCC) components. The clinicopathological characteristics of distinct subtypes of ASC remain unclear.

METHODS

This retrospective study included 226 patients diagnosed with lung ASC who consecutively underwent surgical resection at Shanghai Pulmonary Hospital, Tongji University, between January 2015 and March 2021. Data regarding the clinical features and pathological features were collected.

RESULTS

Out of this study cohort, 125 patients exhibited AC-predominant ASC, while 81 had SCC-predominant ASC. No significant differences were observed between the two subgroups in terms of age, gender, smoking history, primary site, and T, N classification. AC-Predominant ASC displayed a higher susceptibility to genetic alterations compared to SCC-Predominant ASC (P=0.02). Additionally, we showed that irrespective of the predominant pathological subtype in ASC, when lymph node metastasis occurred, the lymph node biopsies were more likely to exhibit AC, and a chi-square test confirmed that the primary predominant pathological subtype was not associated with the lymph node metastasis subtype.

CONCLUSIONS

In conclusion, we describe an overview of ASC in the Chinese population, and upon stratifying into predominant pathological subgroups, we observed a higher frequency of driver gene mutations in AC-predominant ASC. We found that the AC component in ASC has a higher propensity for lymph node metastasis. These findings may suggest the predominant role of the AC component within the context of ASC.

Circulating tumor DNA sequencing of pediatric solid and brain tumor patients: An institutional feasibility study

The potential of circulating tumor DNA (ctDNA) analysis to serve as a real-time "liquid biopsy" for children with central nervous system (CNS) and non-CNS solid tumors remains to be fully elucidated. We conducted a study to investigate the feasibility and potential clinical utility of ctDNA sequencing in pediatric patients enrolled on an institutional clinical genomics trial. A total of 240 patients had tumor DNA profiling performed during the study period. Plasma samples were collected at study enrollment from 217 patients and then longitudinally from a subset of patients. Successful cell-free DNA extraction and quantification occurred in 216 of 217 (99.5%) of these initial samples. Twenty-four patients were identified whose tumors harbored 30 unique variants that were potentially detectable on a commercially-available ctDNA panel. Twenty of these 30 mutations (67%) were successfully detected by next-generation sequencing in the ctDNA from at least one plasma sample. The rate of ctDNA mutation detection was higher in patients with non-CNS solid tumors (7/9, 78%) compared to those with CNS tumors (9/15, 60%). A higher ctDNA mutation detection rate was also observed in patients with metastatic disease (9/10, 90%) compared to non-metastatic disease (7/14, 50%), although tumor-specific variants were detected in a few patients in the absence of radiographic evidence of disease. This study illustrates the feasibility of incorporating longitudinal ctDNA analysis into the management of relapsed or refractory patients with childhood CNS or non-CNS solid tumors.

Evaluation of the Analytical Performance of Oncomine Lung cfDNA Assay for Detection of Plasma EGFR Mutations

BACKGROUND

The clinical utility of circulating tumor DNA (ctDNA) in the early detection of tumor mutations for targeted therapy and the monitoring of tumor recurrence has been reported. However, the analytical validation of ctDNA assays is required for clinical application.

METHODS

This study evaluated the analytical performance of the Oncomine Lung cfDNA Assay compared with the cobas^®EGFR Mutation Test v2. The analytical specificity and sensitivity were estimated using commercially pre-certified reference materials. The comparative evaluation of the two assays was carried out using reference materials and plasma derived from patients diagnosed with lung cancer.

RESULTS

Using 20 ng of input cell-free DNA (cfDNA), the analytical sensitivities for EGFR mutations with variant allele frequencies (VAFs) of 1% and 0.1% were 100% and 100%, respectively. With VAFs of 1.2% and 0.1% using 20 ng of input cfDNA, seven out of nine different mutations in six driver genes were identified in the Oncomine Lung cfDNA Assay. The two assays showed 100% concordance in 16 plasma samples clinically. Furthermore, various PIK3CA and/or TP53 mutations were identified only in the Oncomine Lung cfDNA Assay.

CONCLUSIONS

The Oncomine Lung cfDNA Assay can be used to identify plasma EGFR mutations in patients with lung cancer, although further large-scale studies are required to evaluate the analytical validity for other types of aberrations and genes using clinical samples.

Interpretation of Lung Cancer Plasma EGFR Mutation Tests in the Clinical Setting

OBJECTIVES

Comprehensive data synthesis of the clinical parameters that affect plasma EGFR mutation test results in non-small cell lung carcinoma is lacking. Although individual studies have suggested a variety of patient characteristics that can affect diagnostic accuracy, no unified conclusion has been reached.

METHODS

We analyzed 170 plasma EGFR mutation tests performed between 2015 and 2021 at our institution and carried out a systematic review and meta-analysis to identify clinical and imaging features that correlate with plasma EGFR mutation test sensitivity.

RESULTS

Data synthesis from 14 studies of 2,576 patients revealed that patients with stage IV disease had a significantly lower false-negative rate than those with stage I through III disease. For our institutional cohort, which consisted of 75 paired plasma and tissue tests that were assessable for diagnostic accuracy, the overall sensitivity was 70.59% (95% confidence interval, 56.17%-82.51%). Patients who had distant metastases and more suspicious lymph nodes on imaging findings correlated with a low false-negative rate.

CONCLUSIONS

While interpreting plasma EGFR mutation results, extra caution should be exercised for patients with early-stage, localized disease to accommodate the possibility of false-negative results. These meta-analyses and clinical data may enable clinicians to make evidence-based judgments for individual patients.

Comparison of EGFR mutations detected by LNA-ARMS PCR in plasma ctDNA samples and matched tissue sample in non-small cell lung cancer patients

BACKGROUND

Screening for epidermal growth factor receptor (EGFR) mutations is the key to select suitable patients with non-small cell lung cancer (NSCLC) for EGFR-TKI therapy in clinical practice. Nevertheless, tumor tissue that needed for mutation analysis is frequently unavailable, especially for patients with recurrence after operation. Therefore, detection of EGFR from circulating tumor DNA (ctDNA) in patients with NSCLC is a sensitive and convenient method to direct patient sequential treatment strategy.

METHODS

One hundred and seventy-nine NSCLC patients with both tumor tissue samples and paired plasma samples were recruited. EGFR mutations were detected in 68 tumor tissue samples and 179 plasma samples using Anlongen Locked Nucleic Acid-Amplification Refractory Mutation System (LNA-ARMS) EGFR Mutation Detection Kit. The remaining 111 tumor tissue samples were detected with the use of multiplex PCR-Based NGS sequence. We calculated the sensitivity, specificity, positive prediction value (PPV) and negative prediction value (NPV) of LAN-ARMS PCR. The objective response rate (ORR) of patients received TKIs therapy was calculated.

RESULTS

Of the 179 patients, EGFR mutations were detected in 77 of the 179 tumor tissue samples, with a positive rate of 43.01% (77/179). In addition, EGFR mutations were detected in 42 of the 179 plasma samples. The sensitivity and specificity of LAN-ARMS in detecting EGFR mutations were 57.18% and 98.04% respectively compared to tissue results. The PPV was 95.24%, and NPV was 72.99%. Of the 179 pair of samples, EGFR mutations were inconsistent in 39 pairs of tissue and plasma. The overall agreement of EGFR mutation detection was 78.21% (140/179). The ORR was higher in patients with both tissue and plasma EGFR mutations compared with that in patients with only tissue EGFR mutations (73.33% vs. 68.29%), but the difference was not significant. It was suggested that tissue detection combined with plasma detection could improve the mutation rate.

CONCLUSION

In plasma samples, Anlongen LAN-ARMS EGFR Mutation Detection Kit had a high sensitivity and specificity for the detection of EGFR mutations. Anlongen LAN-ARMS EGFR Mutation Detection Kit had the advantages of easy-to-operate and high sensitivity in clinical application.

Changes in Circulating Tumor DNA Reflect Clinical Benefit Across Multiple Studies of Patients With Non-Small-Cell Lung Cancer Treated With Immune Checkpoint Inhibitors

PURPOSE

As immune checkpoint inhibitors (ICI) become increasingly used in frontline settings, identifying early indicators of response is needed. Recent studies suggest a role for circulating tumor DNA (ctDNA) in monitoring response to ICI, but uncertainty exists in the generalizability of these studies. Here, the role of ctDNA for monitoring response to ICI is assessed through a standardized approach by assessing clinical trial data from five independent studies.

PATIENTS AND METHODS

Patient-level clinical and ctDNA data were pooled and harmonized from 200 patients across five independent clinical trials investigating the treatment of patients with non-small-cell lung cancer with programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1)-directed monotherapy or in combination with chemotherapy. CtDNA levels were measured using different ctDNA assays across the studies. Maximum variant allele frequencies were calculated using all somatic tumor-derived variants in each unique patient sample to correlate ctDNA changes with overall survival (OS) and progression-free survival (PFS).

RESULTS

We observed strong associations between reductions in ctDNA levels from on-treatment liquid biopsies with improved OS (OS; hazard ratio, 2.28; 95% CI, 1.62 to 3.20; P < .001) and PFS (PFS; hazard ratio 1.76; 95% CI, 1.31 to 2.36; P < .001). Changes in the maximum variant allele frequencies ctDNA values showed strong association across different outcomes.

CONCLUSION

In this pooled analysis of five independent clinical trials, consistent and robust associations between reductions in ctDNA and outcomes were found across multiple end points assessed in patients with non-small-cell lung cancer treated with an ICI. Additional tumor types, stages, and drug classes should be included in future analyses to further validate this. CtDNA may serve as an important tool in clinical development and an early indicator of treatment benefit.

Monitoring of the presence of EGFR-mutated DNA during EGFR-targeted therapy may assist in the prediction of treatment outcome

The aim of our trial was to evaluate the prognostic significance of qualitative ctDNA analysis on different stages of EGFR mutated non-small cell lung cancer (NSCLC) treatment. We included 99 patients amendable for the first line treatment with either gefitinib/erlotinib (n = 87), afatinib (n = 10) or osimertinib (n = 2). Sequential qualitative analysis of ctDNA with cobas® EGFR Mutation Test v2 were performed before first dose, after 2 and 4 months of treatment, and on progression. Our analysis showed clinically significant heterogeneity of EGFR-mutated NSCLC treated with 1st line tyrosine kinase inhibitors (TKIs) in terms of progression-free and overall survival. When treated with conventional approach, i.e. monotherapy with TKIs, the patients falls into three subgroups based on ctDNA analysis before and after 2 months of treatment. Patients without detectable ctDNA at baseline (N = 32) possess the best prognosis on duration of treatment (PFS: 24.07 [16.8-31.3] and OS: 56.2 [21.8-90.7] months). Those who achieve clearance after two months of TKI (N = 42) have indistinguishably good PFS (19.0 [13.7 - 24.2]). Individuals who retain ctDNA after 2 months (N = 25) have the worst prognosis (PFS: 10.3 [7.0 - 13.5], p = 0.000). 9/25 patients did not develop ctDNA clearance at 4 months with no statistical difference in PFS from those without clearance at 2 months. Prognostic heterogeneity of EGFR-mutated NSCLC should be taken into consideration in planning further clinical trials and optimizing the outcome of patients.

Impact of detecting plasma EGFR mutations with ultrasensitive liquid biopsy in outcomes of NSCLC patients treated with first- or second-generation EGFR-TKIs

BACKGROUND

Few trials have evaluated the utility of liquid biopsies to detect epidermal growth factor receptor mutations (EGFRm) at the time of response evaluation and its association with the clinical characteristics and outcomes of non-small-cell lung cancer (NSCLC) patients.

OBJECTIVE

This study aimed to evaluate, in a real-world clinical setting, the prevalence of plasma EGFRm and its association with the clinical characteristics, response and survival outcomes of NSCLC patients under treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs).

METHODS

This observational study enrolled advanced or metastatic NSCLC patients, with confirmed tumor EGFRm, receiving treatment with first- or second-generation EGFR-TKIs. Blood samples for the detection of plasma EGFRm were collected at the time of response evaluation and processed using the Target Selector™ assay. The main outcomes were the detection rate of plasma EGFRm, median Progression-Free Survival (PFS) and Overall Survival (OS) according to plasma EGFR mutational status.

RESULTS

Of 84 patients, 50 (59.5%) had an EGFRm detected in plasma. After a median follow-up of 21.1 months, 63 patients (75%) had disease progression. The detection rate of plasma EGFRm was significantly higher in patients with disease progression than in patients with partial response or stable disease (68.3% versus 33.3%; P< 0.01). PFS and OS were significantly longer in patients without plasma EGFRm than among patients with plasma EGFRm (14.3 months [95% CI, 9.25-19.39] vs 11.0 months [95% CI, 8.61-13.46]; P= 0.034) and (67.8 months [95% CI, 39.80-95.94] vs 32.0 months [95% CI, 17.12-46.93]; P= 0.006), respectively. A positive finding in LB was associated with the presence of ⩾ 3 more metastatic sites (P= 0.028), elevated serum carcinoembryonic (CEA) at disease progression (P= 0.015), and an increase in CEA with respect to baseline levels (P= 0.038).

CONCLUSIONS

In NSCLC patients receiving EGFR-TKIs, the detection of plasma EGFRm at the time of tumor response evaluation is associated with poor clinical outcomes.

High discrepancy in thrombotic events in non-small cell lung cancer patients with different genomic alterations

Background

Acute complications, such as venous thromboembolism (VTE), are common in patients with advanced severe lung cancers. However, current VTE risk scores cannot adequately identify high-risk patients with non-small cell lung cancer (NSCLC). The study proposed to elucidated the incidence of thromboembolism (TE) in patients with different oncogenic aberrations and the impact of these aberrations on the efficacy of targeted therapy in patients with NSCLC.

Methods

A systemic review was conducted in Web of Science, PubMed, Embase and the Cochrane Library to evaluate the incidence of TE in different molecular subtypes of NSCLC. Data from patients diagnosed of advanced NSCLC who harboring anaplastic lymphoma kinase (ALK) or ROS proto-oncogene 1 receptor tyrosine kinase (ROS1) rearrangements since 2016 to 2019 were also retrospectively collected. A meta-analysis with random-effects model, sensitivity analysis and publication bias were performed. The principal summary measure was incidence of thrombotic events in NSCLC patients. And the efficacy of tyrosine kinase inhibitor (TKI) therapy was compared between the two subgroups.

Results

A total of 5,767 cases from 20 studies were included in the analysis of the incidence of thrombosis in patients with different oncogenic alterations. The pooled analysis showed a higher risk of thrombosis in ROS1-fusion types (41%, 95% CI: 35-47%) and ALK-fusion types (30%, 95% CI: 24-37%) than in EGFR-mutation (12%, 95% CI: 8-17%), KRAS-mutation (25%, 95% CI: 13-50%), and wild-type (14%, 95% CI: 10-20%) cases. A high prevalence of thrombosis (ALK: 24.4%; ROS1: 32.6%) was observed in the Shanghai Pulmonary Hospital (SPH) cohort of 224 patients with ALK or ROS1 fusion. Furthermore, patients with embolism had significantly shorter progression-free survival (PFS) after TKI therapy than those without embolism, both in the ALK+ cohort (5.6 vs. 12.9 months, P<0.0001) and in the ROS1+ cohort (9.6 vs. 17.6 months, P=0.0481).

Conclusions

NSCLC patients with ALK/ROS1 rearrangements are more likely to develop thrombosis than patients with other oncogenic alterations. Thrombosis may also be associated with an inferior response and PFS after TKI therapy.

Detection of epidermal growth factor receptor mutations in peripheral blood circulating tumor DNA in patients with advanced non-small cell lung cancer: A PRISMA-compliant meta-analysis and systematic review

BACKGROUND

The epidermal growth factor receptor (EGFR) mutation status related to the treatment approach for advanced non-small cell lung cancer (NSCLC) patients. This study aimed to evaluate the diagnostic accuracy of peripheral blood circulating tumor DNA (ctDNA) in EGFR mutated advanced NSCLC patients.

METHOD

The related database was systematically searched with keywords until January 19, 2020. Studies contained the histopathological and cytological advanced NSCLC samples were included, and the diagnostic data were recorded for calculating sensitivity and specificity. I statistics were used for detecting heterogeneity across studies, and the meta-regression was performed to seek the source of heterogeneity.

RESULT

A total of 32 studies with 4527 advanced NSCLC patients were included in our meta-analysis. Among them, 87% of the patients were diagnosed as stage IV. The pooled sensitivity of peripheral blood ctDNA was 0.70 (95% CI: 0.63-0.75, I = 81.76) and the pooled specificity was 0.98 (95% CI: 0.96-0.99, I = 88.33). The meta-regression showed that the prospective study design and the ARMS detection method were the main source of heterogeneity for sensitivity (P < .05), and the publication country (Asia or non-Asia) was the main source of heterogeneity for specificity (P < .01).

CONCLUSION

ctDNA biopsy has high specificity and diagnostic accuracy in detection of EGFR mutation in advanced NSCLC patients. When the ctDNA gene test result is negative, we should fully consider the risk of missed diagnosis, and further tissue biopsy is still needed to undertake.

Circulating Tumor DNA in Biliary Tract Cancer: Current Evidence and Future Perspectives

Peripheral blood of cancer patients "physiologically" presents cells and cellular components deriving from primary or metastatic sites, including circulating tumor cells (CTCs), circulating free DNA (cfDNA) and exosomes containing proteins, lipids and nucleic acids. The term circulating tumor DNA (ctDNA) indicates the part of cfDNA which derives from primary tumors and/or metastatic sites, carrying tumor-specific genetic or epigenetic alterations. Analysis of ctDNA has enormous potential applications in all stages of cancer management, including earlier diagnosis of cancer, identification of driver alterations, monitoring of treatment response and detection of resistance mechanisms. Thus, ctDNA has the potential to profoundly change current clinical practice, by moving from tissue to peripheral blood as a source of information. Herein, we review current literature regarding the potential role for ctDNA in biliary tract cancer (BTC) patients, with a particular focus on state-of-the-art techniques and future perspectives of this highly aggressive disease.

Smoking habit and chemo-radiotherapy and/or surgery affect the sensitivity of EGFR plasma test in non-small cell lung cancer

OBJECTIVE

This study aimed to identify the influential factors for the sensitivity of epidermal growth factor receptor (EGFR) plasma test in non-small cell lung cancer (NSCLC). The mutations were detected in tumor tissue and matched plasma samples from 125 newly diagnosed adenocarcinoma, clinical-stage IIIB-IV patients, and compared the diagnostic values of EGFR plasma test between groups of clinical characteristics. The influential factors for the sensitivity were identified and assessed by logistic regression.

RESULTS

EGFR mutations were detected in 65 (52.0%) tumor tissue and 50 (40.0%) matched plasma samples (P = 0.028). Compared to the tissue method, the concordance rate, sensitivity, and specificity of the EGFR plasma test were 86.4%, 75.4%, and 98.3%, respectively. Notably, we found that sensitivity of the test is higher in non-smokers (84.1%) compared to smokers (57.1%, P = 0.018), and in treatment naïve subjects (85.7%) compared to whom undergone chemo-radiotherapy with/without surgery before testing (56.5%, P = 0.009). Furthermore, the highest sensitivity was attained in patients without these two factors (90.3%), whilst the lowest value was noted in those with both factors (40.0%, P = 0.004). The multivariable analysis confirmed that smoking habit and treatment history have independently negative impacts on sensitivity (OR = 0.24, P = 0.019, and OR = 0.36, P = 0.047, respectively).

Precision Detection Technology: Equipping Precision Oncology with Wings

In recent years, precision medical detection techniques experienced a rapid transformation from low-throughput to high-throughput genomic sequencing, from multicell promiscuous detection to single-cell precision sequencing. The emergence of liquid biopsy technology has compensated for the many limitations of tissue biopsy, leading to a tremendous transformation in precision detection. Precision detection techniques contribute to monitoring disease development more closely, evaluating therapeutic effects more scientifically, and developing new targets and new drugs. In the future, the role of precision detection and the joint detection in epigenetics, rare gene detection, individualized targeted therapy, and multigene targeted drug combination therapy should be extensively explored. This article reviews the changes in precision medical detection technology in the era of precision medicine, as well as the development, clinical application, and future challenges of liquid biopsy.

The Diagnostic Accuracy of Liquid Biopsy in EGFR-Mutated NSCLC: A Systematic Review and Meta-Analysis of 40 Studies

Epidermal growth factor receptor (EGFR) mutations are the most common carcinogenic driver mutations in non-small-cell lung cancer (NSCLC) patients, while invasive tissue biopsy has certain inherent defects. PubMed, Ovid Medline, Embase, and the Cochrane Library were systematically searched on January 4, 2020, using the keywords "liquid biopsy," "EGFR," and "NSCLC." The pooled sensitivity and specificity of EGFR mutations in paired tissue and blood were calculated. The accuracy was assessed by receiver operating characteristic curve. The meta-regression of the subgroup was performed to analyze the heterogeneity. Hazard ratio (HR) and 95% confidence interval (CI) were combined for evaluating the impact of EGFR mutation in tissue and liquid blood biopsy. A total of 40 studies with 5,995 patients were involved in the study. The pooled sensitivity was 68% (95% CI = 60-75%), and the specificity was 98% (95% CI = 95-99%). The diagnostic odds ratio was 88 (95% CI = 40-195), and the area under the curve was 0.91 (95% CI = 0.88-0.93). In the meta-regression, the sensitivity and specificity remain lower in the Asian studies than non-Asian studies (sensitivity: 66% vs. 73%, P = 0.04; specificity: 96% vs. 97%, P = 0.03, respectively). The EGFR mutation was associated with a better progression-free survival than wild type in both tissue (HR = 0.54, 95% CI = 0.34-0.85, P = 0.007) and blood (HR = 0.81, 95% CI = 0.71-0.92, P = 0.001) detection. Peripheral blood liquid biopsy had a better specificity for detecting EGFR mutation in NSCLC patients, while tissue biopsy still needs to be undertaken for negative blood biopsy patients due to its lower sensitivity.

The Validity and Predictive Value of Blood-Based Biomarkers in Prediction of Response in the Treatment of Metastatic Non-Small Cell Lung Cancer: A Systematic Review

With the introduction of targeted therapies and immunotherapy, molecular diagnostics gained a more profound role in the management of non-small cell lung cancer (NSCLC). This study aimed to systematically search for studies reporting on the use of liquid biopsies (LB), the correlation between LBs and tissue biopsies, and finally the predictive value in the management of NSCLC. A systematic literature search was performed, including results published after 1 January 2014. Articles studying the predictive value or validity of a LB were included. The search (up to 1 September 2019) retrieved 1704 articles, 1323 articles were excluded after title and abstract screening. Remaining articles were assessed for eligibility by full-text review. After full-text review, 64 articles investigating the predictive value and 78 articles describing the validity were included. The majority of studies investigated the predictive value of LBs in relation to therapies targeting the epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) receptor (n = 38). Of studies describing the validity of a biomarker, 55 articles report on one or more EGFR mutations. Although a variety of blood-based biomarkers are currently under investigation, most studies evaluated the validity of LBs to determine EGFR mutation status and the subsequent targeting of EGFR tyrosine kinase inhibitors based on the mutation status found in LBs of NSCLC patients.

Diagnostic Accuracy of Droplet Digital PCR and Amplification Refractory Mutation System PCR for Detecting EGFR Mutation in Cell-Free DNA of Lung Cancer: A Meta-Analysis

Background: Epidermal growth factor receptor (EGFR) mutation testing in plasma cell-free DNA (cfDNA) from advanced lung cancer patients is an emerging clinical tool. This meta-analysis was designed to determine the diagnostic accuracy of two common PCR systems, droplet digital PCR (ddPCR) and amplification refractory mutation system PCR (ARMS-PCR), for detecting EGFR mutation in cfDNA.

Materials and methods: A systematic search was carried out based on PubMed, Web of science, Embase and the Cochrane library. Data from eligible studies were extracted and pooled to calculate the sensitivity, specificity, diagnostic odds ratio (DOR), area under the summary receiver-operating characteristic curve (AUROC), using tissue biopsy results as the standard method. Subgroup analyses were performed regarding EGFR mutation type, tumor stage, and EGFR-TKI treatment.

Results: Twenty-five studies involving 4,881 cases were included. The plasma testing sensitivity, specificity, DOR, and AUROC, compared with the matched tumor tissues, were 72.1%, 95.6%, 38.5, 0.89 for ddPCR, and 65.3%, 98.2%, 52.8, 0.71 for ARMS-PCR, respectively, through indirect comparison, significant differences were found in sensitivity (P = 0.003) and specificity (P = 0.007). Furthermore, significant difference was found in sensitivity between tumor stage subgroups (IIIB–IV subgroup vs. IA–IV subgroup) in ARMS-PCR (73.7 vs. 64.2%, P = 0.008), but not in ddPCR (72.5 vs. 71.2%, P = 0.756).

Conclusions: This study demonstrates that ddPCR and ARMS-PCR have a high specificity with a practical sensitivity for detecting EGFR mutation in cfDNA, which supports their application as a supplement or a conditional-alternative to tissue biopsy in clinical practice for genotyping. It seems that ddPCR has a higher sensitivity than ARMS-PCR, especially in early stages.

Detection of plasma EGFR mutations for personalized treatment of lung cancer patients without pathologic diagnosis

INTRODUCTION

Next-generation sequencing (NGS) and digital polymerase chain reaction (PCR) based platforms have been used to detect EGFR mutations in plasma circulating tumor DNA (ctDNA) with high accuracy. Generally, molecular testing is performed after histopathological analysis. However, many patients with suspected advanced nonsmall cell lung cancer are unable to undergo biopsy thus forgoing potential treatment with highly effective tyrosine kinase inhibitors (TKIs) in patients with sensitizing EGFR mutations. We examined the utility of ctDNA testing to detect EGFR mutations in patients' plasma, where tissue biopsy is not feasible.

METHODS

We conducted a single-center, prospective study of 30 Chinese patients with suspected advanced lung cancer, who were unable to undergo a biopsy for initial diagnosis due to comorbidities or poor performance status. Patients with plasma EGFR sensitizing mutations were treated with first-generation EGFR TKIs.

RESULTS

Twenty of 30 patients enrolled had sensitizing EGFR mutations in ctDNA and were started on EGFR TKIs. After a median follow-up of 12 months, median progression-free survival (PFS) was 10 months and median overall survival (OS) was not reached. The median OS for the 10 untreated patients was 3 months.

CONCLUSIONS

In our study, patients with plasma EGFR mutations treated with TKIs showed disease control rate (DCR) and PFS similar to historical controls that were treated based on tissue testing. This is the first prospective study showing that ctDNA genotyping provides a feasible diagnostic approach for frail lung cancer patients who are unable to undergo biopsy, which subsequently leads to EGFR-targeted therapy, and improved outcomes in this subgroup of patients.

Differential significance of molecular subtypes which were classified into EGFR exon 19 deletion on the first line afatinib monotherapy

BACKGROUND

Epidermal growth factor receptor (EGFR)-sensitizing mutation, exon 19 deletion consists of several molecular variants. Influences of these variants on clinical response to EGFR tyrosine kinase inhibitors remain elusive.

METHODS

West Japan Oncology Group 8114LTR is a prospective, multi-institutional biomarker study. Treatment naïve, advanced non-small-cell lung cancer patients with EGFR-sensitizing mutation received afatinib monotherapy. We conducted a preplanned subset analysis of patients harboring exon 19 deletion. Tumor tissue exon 19 deletion molecular variants were identified by blocking-oligo-dependent polymerase chain reaction (PCR) and by Luminex Technology. Plasma cfDNA was also obtained before and after the treatment and EGFR mutations were detected with multiplexed, pico-droplet digital PCR assay.

RESULTS

Among 57 registered patients, twenty-nine patients were exon 19 deletion. Tissue DNA and cfDNA were available in 26 patients. Among the detected seven molecular variants, the most frequent was p.E746_A750delELREA (65.4%). According to the various classifications of molecular variants, twenty one (80.8%) were classified into 15-nucleotide deletion, one (3.8%) into 18-nucleotide deletion, and four patients (15.4%) into other insertion/substitution variant subgroups. The patient subgroup with 15-nucleotide deletion showed significantly longer progression-free survival than patients in other mixed insertion/substitution variant subgroup (p = 0.0244).

CONCLUSIONS

The clinical significance of molecular variants of exon 19 deletion on the first line afatinib monotherapy is reported here for the first time. Further investigation is needed for development of better therapeutic strategies.

TRIAL REGISTRATION

This trial was registered at UMIN Clinical Trials Registry at 2014/12/4 (UMIN000015847).

Assessing the Concordance of Genomic Alterations between Circulating-Free DNA and Tumour Tissue in Cancer Patients

Somatic alterations to the genomes of solid tumours, which in some cases represent actionable drivers, provide diagnostic and prognostic insight into these complex diseases. Spatial and longitudinal tracking of somatic genomic alterations (SGAs) in patient tumours has emerged as a new avenue of investigation, not only as a disease monitoring strategy, but also to improve our understanding of heterogeneity and clonal evolution from diagnosis through disease progression. Furthermore, analysis of circulating-free DNA (cfDNA) in the so-called "liquid biopsy" has emerged as a non-invasive method to identify genomic information to inform targeted therapy and may also capture the heterogeneity of the primary and metastatic tumours. Considering the potential of cfDNA analysis as a translational laboratory tool in clinical practice, establishing the extent to which cfDNA represents the SGAs of tumours, particularly actionable driver alterations, becomes a matter of importance, warranting standardisation of methods and practices. Here, we assess the utilisation of cfDNA for molecular profiling of SGAs in tumour tissue across a broad range of solid tumours. Moreover, we examine the underlying factors contributing to discordance of detected SGAs between cfDNA and tumour tissue.

Towards Circulating-Tumor DNA-Based Precision Medicine

In the era of precision medicine, targeted therapies have been implemented for various diseases. Genomic information guides decision-making in cancer treatment. The improvements in next-generation sequencing and polymerase chain reaction have made it possible to access the genetic information using circulating-tumor DNAs (ctDNAs). Molecular characteristics of individual tumors can be obtained by analysis of ctDNAs, thus making them excellent tools to guide decision-making during treatment. In oncology, the use of ctDNAs in clinical practice is now gaining importance. Molecular analysis of ctDNAs has potential for multiple clinical applications, including early diagnosis, prognosis of disease, prognostic and/or predictive biomarkers, and monitoring response to therapy and clonal evolution. In this paper, we highlight the applications of ctDNAs in cancer management, especially in metastatic setting, and summarize recent studies about the use of ctDNAs as predictive biomarkers for the therapeutic adaptation/response in lung cancer, breast cancer, and colorectal cancer. These studies offer the evidence to use ctDNAs as a promising approach to solve unmet clinical needs.

A comparison of EGFR mutation status in tissue and plasma cell-free DNA detected by ADx-ARMS in advanced lung adenocarcinoma patients

Background

Previous studies have shown that there are different methods used to detect the epidermal growth factor receptor (EGFR) mutation status in plasma cell-free DNA (cfDNA) for advanced lung adenocarcinoma patients including the ADx-Amplification Refractory Mutation System (ADx-ARMS). We explored the performance of the ADx-ARMS in detecting the EGFR mutations in cfDNA.

Methods

This prospective cohort study enrolled patients who presented with advanced (stage IIIb/IV) lung adenocarcinoma. EGFR mutations in plasma cfDNA and tumor tissues by ADx-ARMS were detected. Next-generation sequencing (NGS) in plasma was performed in patients with inconsistent gene region mutations in the plasma and matched tissue samples. We calculated the clinical parameters of the ADx-ARMS for EGFR mutation status in the plasma of cfDNA, using the tumor tissues as the standard for measurement. The objective response rate (ORR) and progression-free survival (PFS) were also calculated for patients receiving first-generation EGFR-tyrosine kinase inhibitors (TKIs) therapy.

Results

In total, 203 patients were included in the final analysis. Mutations were discovered in 58.6% (119/203) of the tumor tissues and 31.0% (63/203) were detected EGFR mutations in both tumor tissues and matched plasma. The sensitivity and the specificity setting for detecting the EGFR mutations in the plasma using the ADx-ARMS were configured to 52.9% and 98.8%. An ORR of 64.8% was observed among the 71 patients who were identified as being EGFR-positive in their tumor tissues, who had received treatments using Gefitinib or Icotinib. Next, the ORR was observed to be 69.0% among the 42 patients with an EGFR mutation in their plasma. The median PFS of the patients with an EGFR mutation in tumor tissues and plasma were 10.0 vs. 11.0 months (P=0.175). The median PFS of the patients with an EGFR wild-type in the plasma was 8.7 months, which was significantly shorter than the EGFR mutant-type in plasma (P=0.001).

Conclusions

Using ADx-ARMS as an approach with high specificity but moderate sensitivity to detect the EGFR mutations in plasma cfDNA and EGFR mutation status in plasma cfDNA using the ADx-ARMS can predict the tumor response for EGFR-TKIs.

Emerging Molecular Technologies in Renal Cell Carcinoma: Liquid Biopsy

Liquid biopsy, based on the circulating tumor cells (CTCs) and cell-free nucleic acids has potential applications at multiple points throughout the natural course of cancer, from diagnosis to follow-up. The advantages of doing ctDNA assessment vs. tissue-based genomic profile are the minimal procedural risk, the possibility to serial testing in order to monitor disease-relapse and response to therapy over time and to reduce hospitalization costs during the entire process. However, some critical issues related to ctDNA assays should be taken into consideration. The sensitivity of ctDNA assays depends on the assessment technique and genetic platforms used, on tumor-organ, stage, tumor heterogeneity, tumor clonality. The specificity is usually very high, whereas the concordance with tumor-based biopsy is generally low. In patients with renal cell carcinoma (RCC), qualitative analyses of ctDNA have been performed with interesting results regarding selective pressure from therapy, therapeutic resistance, exceptional treatment response to everolimus and mutations associated with aggressive behavior. Quantitative analyses showed variations of ccfDNA levels at different tumor stage. Compared to CTC assay, ctDNA is more stable than cells and easier to isolate. Splice variants, information at single-cell level and functional assays along with proteomics, transcriptomics and metabolomics studies can be performed only in CTCs.

First-line continual EGFR-TKI plus local ablative therapy demonstrated survival benefit in EGFR-mutant NSCLC patients with oligoprogressive disease

Introduction: The effect of local ablative therapy (LAT) for oligoprogressive epidermal growth factor receptor (EGFR) mutation non-small cell lung cancer (NSCLC) remains undetermined. This study aimed to investigate the survival benefit of addition of LAT to EGFR-TKIs in EGFR-mutant NSCLC patients with oligoprogression during TKI therapy.

Materials and Methods: Patients with stage IIIB/IV EGFR mutant NSCLC who had oligoprogressive disease during the first-line EGFR-TKI therapy from March 2011 to February 2016 were identified. The primary research point were progression-free survival1 (PFS1), defined as time of initiation of TKI therapy to Response Evaluation Criteria in Solid Tumours (RECIST) 1.1 defined progress disease (PD) or death and PFS2, defined as time of initiation of TKI therapy to off-TKI PD. The second research piont inclued overal survival (OS) and safety.

Results: A total of 206 patients were included. The median follow-up time was 42 months (20.0-69.6 months). The median PFS1, median PFS2 and median OS for the related cohort were 10.7 months (95% CI, 10.1-13.3 months), 18.3 months (95% CI, 17.4-19.2 months) and 37.4 months (95% CI, 35.9-38.9 months) respectively. Survival rates of 1 year, 2 years and 3 years were 94.1%, 78.9%, and 54.7%, respectively. Multivariate analysis revealed that female, EGFR exon 19 mutation, one metastatic lesion, partial or complete response to prior EGFR TKIs therapy were the independent prognostic factors. No unexpected toxicities were observed.

Conclusion: The current study suggested that the addition of LAT to EGFR-TKI could provide satisfactory survival benefit for EGFR-mutant NSCLC patients with oligoprogression during first-line EGFR-TKI treatment.

Dynamic Monitoring and Predictive Value of Circulating Tumor Cells in EGFR-Mutated Advanced Non-Small-Cell Lung Cancer Patients Treated With First-Line EGFR Tyrosine Kinase Inhibitors

BACKGROUND

There is an urgent need to develop a convenient and less invasive technique to monitor the efficacy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in patients with EGFR-mutated non-small-cell lung cancer (NSCLC). We proposed folate receptor-based assay to count circulating tumor cells (CTCs) to predict and dynamically monitor the therapeutic response to first-line EGFR-TKIs in patients with EGFR-mutated NSCLC.

PATIENTS AND METHODS

Eligible patients were enrolled, and 3 mL of blood was obtained before initial treatment, 1 month after treatment, and every 2 months thereafter. CTCs were isolated on the basis of negative enrichment by immunomagnetic beads and detected by a ligand-targeted PCR method.

RESULTS

A total of 232 patients with EGFR-mutated NSCLC and treated with first-line EGFR-TKIs were included. Patients with low baseline CTC count had a markedly longer progression-free survival (hazard ratio = 0.48; P < .001) and overall survival (hazard ratio = 0.52; P = .002) than those with high count. This difference remained significant in multivariate analysis. Dynamic change of CTC count was significantly associated with partial response (P = .042) and stable disease/progressive disease (P = .032). Notably, dynamic monitoring of CTC provided evidence of resistance to EGFR-TKIs before computed tomographic scanning with a median lead time of 113 days (range, 45-169 days).

CONCLUSION

The current evidence suggests that folate receptor-positive CTC counts can be used for both the dynamic monitoring and prediction of outcome in EGFR-mutated NSCLC patients treated with EGFR-TKIs, which could serve as an alternative or supplement to computed tomographic scanning.

Epidermal growth factor receptor T790M mutations in non-small cell lung cancer (NSCLC) of Yunnan in southwestern China

To explore the effect of epidermal growth factor receptor (EGFR) T790M mutation status on non-small cell lung cancer (NSCLC) in Yunnan province of southwestern China. First, this study used the super amplification refractory mutation system (Super ARMS) polymerase chain reaction (PCR) and Droplet Digital PCR (dd PCR) to evaluate the T790M gene mutation, in plasmatic ctDNA samples from 212 cases of NSCLC. The association between T790M mutations and clinical parameters were further explored. Next, to investigate the mechanism of drug resistance that resulted from T790M mutation, subgroup analyses according to duration of medicine (EGFR-TKIs) were carried out. Finally, we also evaluate the effectiveness of blood-based circulating tumor DNA (ctDNA) on detecting the T790M mutation by calculating Super ARMS’s detection efficiency. We found that the T790M mutation rate was 8.4% (18/212) in overall patients. The T790M mutation was more frequent in patients with brain metastasis 30.0% (12/40) (p < 0.01). We found that post-TKI samples 42.8% (15/35) were associated with a higher T790M mutation rate (p < 0.01). Subgroup analysis showed that the duration of TKI therapy for 6 to 10 months 66.6% (8/12) (p < 0.01) and >10 months 75.0% (9/12) (p < 0.01) were also associated with a higher T790M mutation rate. Super ARMS’s sensitivity, specificity, PPV, NPV, and accuracy were 100.0%, 99.4%, 94.7%, 100.0%, and 99.5% respectively. Generally, the EGFR-T790M mutation was more common in NSCLC patients with brain metastasis and those who received TKI therapy for more than 6 months. Moreover, Super ARMS is a sensitive, efficient, and practical clinic method for dynamically monitoring T790M mutation status and effectively guiding clinic treatment.

Clinical utility of a blood-based EGFR mutation test in patients receiving first-line erlotinib therapy in the ENSURE, FASTACT-2, and ASPIRATION studies

OBJECTIVE

Patients with advanced non-small-cell lung cancer (NSCLC) with an adenocarcinoma component are recommended to undergo epidermal growth factor receptor (EGFR) mutation testing when being considered for EGFR targeted therapy. We conducted an exploratory analysis to inform the clinical utility of EGFR mutation testing in blood cell-free DNA using the cobas^®EGFR Mutation Test v2.

MATERIALS AND METHODS

Two EGFR mutation tests, a tissue-based assay (cobas^® v1) and a tissue- and blood-based assay (cobas^® v2) were used to analyze matched biopsy and blood samples (897 paired samples) from three Asian studies of first-line erlotinib with similar intent-to-treat populations. ENSURE was a phase III comparison of erlotinib and gemcitabine/platinum, FASTACT-2 was a phase III study of gemcitabine/platinum plus erlotinib or placebo, and ASPIRATION was a single-arm phase II study of erlotinib. Agreement statistics were evaluated, based on sensitivity and specificity between the two assays in subgroups of patients with increasing tumor burden.

RESULTS

Patients with discordant EGFR (tissue+/plasma-) mutation status achieved longer progression-free and overall survival than those with concordant (tissue+/plasma+) mutation status. Tumor burden was significantly greater in patients with concordant versus discordant mutations. Pooled analyses of data from the three studies showed a sensitivity of 72.1% (95% confidence interval [CI] 67.8-76.1) and a specificity of 97.9% (95% CI 96.0-99.0) for blood-based testing; sensitivity was greatest in patients with larger baseline tumors.

CONCLUSIONS

Blood-based EGFR mutation testing demonstrated high specificity and good sensitivity, and offers a convenient and easily accessible diagnostic method to complement tissue-based tests. Patients with a discordant mutation status in plasma and tissue, had improved survival outcomes compared with those with a concordant mutation status, which may be due to their lower tumor burden. These data help to inform the clinical utility of this blood-based assay for the detection of EGFR mutations.

Real-world EGFR testing in patients with stage IIIB/IV non-small-cell lung cancer in North China: A multicenter, non-interventional study

BACKGROUND

Before tyrosine kinase inhibitor (TKI) therapy can be administered in patients with advanced non-small cell lung cancer (NSCLC), EGFR mutation testing is required. However, few studies have evaluated the extent of EGFR testing in real-world practice in China.

METHODS

A multicenter, observational study of EGFR testing in NSCLC patients in North China was conducted. Treatment-naïve patients or those with postoperative recurrent stage IIIB/IV NSCLC were enrolled. The primary objective was EGFR testing rate. Secondary objectives included EGFR mutation status, EGFR testing methods and specimens, factors associated with EGFR testing, and overall survival with or without EGFR testing.

RESULTS

Overall, 2809 patients with stage IIIB/IV NSCLC were enrolled; 90.78% had adenocarcinoma. The EGFR screening rate was 42.54%. EGFR testing rates were higher in tumor samples obtained by lymph node puncture, and in patients with urban medical insurance, adenocarcinoma, non-smokers, or those located in developed cities (all P < 0.001). The EGFR mutation rate was 46.44%. The most commonly used specimens for EGFR testing were biopsy tumor samples (67.53%). PCR-based methods (72.05%), Sanger sequencing (5.36%), and Luminex liquid chip (5.10%) were the most frequently used testing platforms. Similar positive EGFR mutation rates were achieved with different platforms. TKI therapy was the first-line treatment administered to most EGFR-positive patients (56.22%), and chemotherapy in EGFR-negative patients (84.88%). Overall survival was higher in EGFR-tested than in untested patients (27.50 vs. 19.73 months; P = 0.007).

CONCLUSION

Real-world EGFR testing rates for NSCLC in North China were relatively low because of clinical and social factors, including medical insurance coverage.

Auxiliary variable-enriched biomarker-stratified design

Clinical trials in the era of precision medicine require assessment of biomarkers to identify appropriate subgroups of patients for targeted therapy. In a biomarker-stratified design (BSD), biomarkers are measured on all patients and used as stratification variables. However, such a trial can be both inefficient and costly, especially when the prevalence of the subgroup of primary interest is low and the cost of assessing the biomarkers is high. Efficiency can be improved and costs reduced by using enriched biomarker-stratified designs, in which patients of primary interest, typically the biomarker-positive patients, are oversampled. We consider a special type of enrichment design, an auxiliary variable-enriched design (AEBSD), in which enrichment is based on some inexpensive auxiliary variable that is positively correlated with the true biomarker. The proposed AEBSD reduces the total cost of the trial compared with a standard BSD when the prevalence rate of true biomarker positivity is small and the positive predictive value (PPV) of the auxiliary biomarker is larger than the prevalence rate. In addition, for an AEBSD, we can immediately randomize the patients selected in the screening process without waiting for the result of the true biomarker test, reducing the treatment waiting time. We propose an adaptive Bayesian method to adjust the assumed PPV while the trial is ongoing. Numerical studies and an example illustrate the approach. An R package is available.

Tissue or blood: which is more suitable for detection of EGFR mutations in non-small cell lung cancer?

BACKGROUND

Many studies have evaluated the accuracy of EGFR mutation status in blood against that in tumor tissues as the reference. We conducted this systematic review and meta-analysis to assess whether blood can be used as a substitute for tumor tissue in detecting EGFR mutations.

METHODS

Investigations that provided data on EGFR mutation status in blood were searched in the databases of Medline, Embase, Ovid Technologies and Web of Science. The detect efficiency of EGFR mutations in paired blood and tissues was compared using a random-effects model of meta-analysis. Pooled sensitivity and specificity and diagnostic accuracy were calculated by receiver operating characteristic curve.

RESULTS

A total of 19 studies with 2,922 individuals were involved in this meta-analysis. The pooled results showed the positive detection rate of EGFR mutations in lung cancer tissues was remarkably higher than that of paired blood samples (odds ratio [OR] = 1.47, p<0.001). The pooled sensitivity and specificity of blood were 0.65 and 0.91, respectively, and the area under the receiver operating characteristic curve was 0.89.

CONCLUSIONS

Although blood had a better specificity for detecting EGFR mutations, the absence of blood positivity should not necessarily be construed as confirmed negativity. Patients with negative results for blood should decidedly undergo further biopsies to ascertain EGFR mutations.

A Case-control Study Supporting the Use of Liquid Biopsy in the Targeted Therapy for Lung Cancer

Backgrounds

Targeted therapy for lung cancer depends on the genetic testing. Liquid biopsy provides a valuable source for the genetic testing. However, direct evidence was lacking for whether liquid biopsy could guide the targeted therapy.

Methods

In this retrospective study, the admitted patients from Jan 2015 to Feb 2016 were screened through a pre-established database. Patients with metastatic, pathologically-confirmed, and treatment naïve non-small cell lung cancer who were prescribed with epithelial growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) from the guidance of liquid biopsy were enrolled (Liquid group). The mutation status in tumors was not mandatory. During the same period, patients medicated with TKI based on tumor samples were included in the Control group. They were enrolled in an age-, gender-, performance-, smoking-, and histology-matched manner.

Results

We screened 536 patients and enrolled 26 patients in the Liquid group. Another 26 patients were enrolled in a 1:1 ratio in the Control group. In the Liquid group, a high consistence (84.6%) in EGFR mutation status between liquid and tumor was observed. The best response was partial response in 19 patients (73.1 %), and followed by stable disease in 6 patients (23.1 %). The median progression-free survival was 10.0 months (95%CI: 4.2-15.8 months). In the Control group, a similar disease control rate (88.4%, P=0.603) and comparable PFS (8.6 months, 95% CI: 7.6-10.4 months, P=0.714, HR=0.657, 95% CI: 0.309-1.396) was found. In the Liquid group, 3 of 4 patients with discordant results between tumor and liquid biopsy showed treatment responses favoring the liquid biopsy.

Conclusion

This study provided direct evidence supporting the liquid biopsy for guiding the targeted therapy for lung cancer.

Liquid Biopsy as Surrogate to Tissue in Lung Cancer for Molecular Profiling: A Meta-Analysis

Background:

The accurate microscopic diagnosis of lung cancer has become insufficient due to the concept of personalized medicine. Tissue samples are used not only for microscopic diagnosis but also for the assessment of the different targets. Biopsies are performed in 80% of the patients and they are not sufficient for molecular diagnosis in 30% of the cases. Liquid biopsy (LB) has been reported as a possible surrogate to tissue samples and has been introduced in the management scheme of the patients since 2014. We aimed to highlight the diagnostic value of liquid biopsy in assessing the molecular profile of non small cell carcinomas in comparison with tissue biopsy.

Methods:

We retracted eligible articles from PubMed, Embase and Cochrane databases. We calculated the pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR). A summary receiver operating characteristic curve (SROC) and area under curve (AUC) were used to evaluate the overall diagnostic performance using the Meta-Disc software 5.1.32. The heterogeneity was assessed using I square statistics. A meta-regression was performed in case of heterogeneity. In case of absence of covariates, a sensitivity analysis was done in order to assess publications that induced a statistical bias.

Results:

39 eligible studies involving 4782 patients were included. The overall statistical studies showed heterogeneity in the SEN, SPE, PLR, NLR and DOR. No threshold effect was revealed. The meta-regression incorporating the ethnicity, the test, the technique used in tissue and plasma and the use of plasma or serum as covariates showed no impact of these factors. A sensitivity analysis allowed achieving the homogeneity in the SPE and DOR. The overall pooled SEN and SPE were 0.61 and 0.95 respectively. The PLR was 9.51, the NLR was 0.45 and DOR was 24.58. The SROC curve with AUC of 0,93 indicated that the liquid biopsy is capable of identifying wild type samples from mutated ones with a relatively high accuracy.

Conclusion:

This meta-analysis suggested that detection of molecular mutations by cfDNA is of adequate diagnostic accuracy in association to tissues. The high specificity and the moderate sensitivity highlight the value of LB as a screening test

A liquid biopsy in primary lung cancer

A tissue biopsy is the "golden standard" for molecular profiling that is essential in decision-making regarding treatment for malignant tumors, including primary lung cancer. However, tumor biopsies are associated with several limitations, including invasiveness and difficulty in achieving access. Liquid biopsies have several potential advantages over tissue biopsies, and recent advances in molecular technologies have enabled liquid biopsies to be introduced into daily clinical practice. Cell-free blood-based liquid biopsies to detect mutations in the epidermal growth factor receptor (EGFR) gene in the plasma have been approved and may be useful in selecting patients for treatment with tyrosine kinase inhibitors of EGFR. We herein describe blood-based liquid biopsies and review the current status and future perspectives of plasma genotyping in primary lung cancer.

Circulating Tumor DNA Analysis in Patients With Cancer: American Society of Clinical Oncology and College of American Pathologists Joint Review

PURPOSE.—

Clinical use of analytical tests to assess genomic variants in circulating tumor DNA (ctDNA) is increasing. This joint review from the American Society of Clinical Oncology and the College of American Pathologists summarizes current information about clinical ctDNA assays and provides a framework for future research.

METHODS.—

An Expert Panel conducted a literature review on the use of ctDNA assays for solid tumors, including preanalytical variables, analytical validity, interpretation and reporting, and clinical validity and utility.

RESULTS.—

The literature search identified 1338 references. Of those, 390, plus 31 references supplied by the Expert Panel, were selected for full-text review. There were 77 articles selected for inclusion.

CONCLUSIONS.—

The evidence indicates that testing for ctDNA is optimally performed on plasma collected in cell stabilization or EDTA tubes, with EDTA tubes processed within 6 hours of collection. Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens, and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity or clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, reevaluation of the literature will shortly be required, along with the development of tools and guidance for clinical practice.

Circulating Tumor DNA Analysis in Patients With Cancer: American Society of Clinical Oncology and College of American Pathologists Joint Review

Purpose Clinical use of analytical tests to assess genomic variants in circulating tumor DNA (ctDNA) is increasing. This joint review from ASCO and the College of American Pathologists summarizes current information about clinical ctDNA assays and provides a framework for future research. Methods An Expert Panel conducted a literature review on the use of ctDNA assays for solid tumors, including pre-analytical variables, analytical validity, interpretation and reporting, and clinical validity and utility. Results The literature search identified 1,338 references. Of those, 390, plus 31 references supplied by the Expert Panel, were selected for full-text review. There were 77 articles selected for inclusion. Conclusion The evidence indicates that testing for ctDNA is optimally performed on plasma collected in cell stabilization or EDTA tubes, with EDTA tubes processed within 6 hours of collection. Some ctDNA assays have demonstrated clinical validity and utility with certain types of advanced cancer; however, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer. Evidence shows discordance between the results of ctDNA assays and genotyping tumor specimens and supports tumor tissue genotyping to confirm undetected results from ctDNA tests. There is no evidence of clinical utility and little evidence of clinical validity of ctDNA assays in early-stage cancer, treatment monitoring, or residual disease detection. There is no evidence of clinical validity and clinical utility to suggest that ctDNA assays are useful for cancer screening, outside of a clinical trial. Given the rapid pace of research, re-evaluation of the literature will shortly be required, along with the development of tools and guidance for clinical practice.

Circulating tumor DNA testing in advanced non-small cell lung cancer

Circulating tumor DNA (ctDNA) shed from cancer cells into the peripheral blood can be non-invasively collected and tested for the presence of tumor-specific mutations. Mutations identified in ctDNA can predict responses to targeted therapies and emerging evidence suggests that changes in ctDNA levels over time can be used to monitor response to therapy and detect disease recurrence. Given the emergence of targeted therapies in advanced non-small cell lung cancer (NSCLC), liquid biopsies utilizing ctDNA testing represent a powerful approach to genotype tumors and monitor for the development of resistance. Here, we review current and potential future clinical applications of ctDNA testing for patients with advanced NSCLC.

Total DNA input is a crucial determinant of the sensitivity of plasma cell-free DNA EGFR mutation detection using droplet digital PCR

We evaluated the use of droplet digital PCR (ddPCR) to detect plasma cell-free DNA (cfDNA) epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung cancer (NSCLC) patients. Compared with tumor-tissue-based detection, the sensitivity of ddPCR for detecting plasma cfDNA tyrosine kinase inhibitor (TKI)-sensitizing EGFR mutations was 61.3%, the specificity was 96.7%, and the consistency rate was 81.4% (?=0.605, 95% confidence interval: 0.501-0.706, p <0.0001). The sensitivity declined from 82.6% to 46.7% with decreasing cfDNA inputs (p=0.028). The plasma cfDNA concentration correlated with gender (males vs.females =11.69 ng/mL vs. 9.508 ng/mL; p=0.044), EGFR mutation status (tumor-tissue EGFR mutation-positive (EGFR M+) vs. EGFR mutation-negative (EGFR M-) = 9.61 ng/mL vs. 12.82 ng/mL; p =0.049) and specimen collection time (=2 years vs. >2 years=13.83 ng/mL vs. 6.575 ng/mL; p <0.001), and was greater in tumor-tissue EGFR M+ / plasma EGFR M+ patients than in tumor-tissue EGFR M+/plasma EGFR M- patients (11.61 vs. 7.73 ng/mL, respectively; p=0.003). Thus total cfDNA input crucially influences the sensitivity of plasma cfDNA EGFR mutation testing with ddPCR. Such analysis could be an effective supplemental test for advanced NSCLC patients.

Incorporating blood-based liquid biopsy information into cancer staging: time for a TNMB system?

Tissue biopsy is the standard diagnostic procedure for cancer. Biopsy may also provide material for genotyping, which can assist in the diagnosis and selection of targeted therapies but may fall short in cases of inadequate sampling, particularly from highly heterogeneous tumors. Traditional tissue biopsy suffers greater limitations in its prognostic capability over the course of disease, most obviously as an invasive procedure with potential complications, but also with respect to probable tumor clonal evolution and metastasis over time from initial biopsy evaluation. Recent work highlights circulating tumor DNA (ctDNA) present in the blood as a supplemental, or perhaps an alternative, source of DNA to identify the clinically relevant cancer mutational landscape. Indeed, this noninvasive approach may facilitate repeated monitoring of disease progression and treatment response, serving as a means to guide targeted therapies based on detected actionable mutations in patients with advanced or metastatic solid tumors. Notably, ctDNA is heralding a revolution in the range of genomic profiling and molecular mechanisms to be utilized in the battle against cancer. This review will discuss the biology of ctDNA, current methods of detection and potential applications of this information in tumor diagnosis, treatment, and disease prognosis. Conventional classification of tumors to describe cancer stage follow the TNM notation system, heavily weighting local tumor extent (T), lymph node invasion (N), and detectable metastasis (M). With recent advancements in genomics and bioinformatics, it is conceivable that routine analysis of ctDNA from liquid biopsy (B) may make cancer diagnosis, treatment, and prognosis more accurate for individual patients. We put forward the futuristic concept of TNMB tumor classification, opening a new horizon for precision medicine with the hope of creating better outcomes for cancer patients.

Liquid Biopsies in the Screening of Oncogenic Mutations in NSCLC and its Application in Targeted Therapy

Non-small cell lung cancer (NSCLC) still dominates cancer-related deaths in America. Despite this, new discoveries and advancements in technology are helping with the detection and treatment of NSCLC. The discovery of circulating tumor DNA in blood and other biofluids is essential for the creation of a DNA biomarker. Limitations in technology and sequencing have stunted assay development, but with recent advancements in the next-generation sequencing, droplet digital PCR, and EFIRM, the detection of mutations in biofluids has become possible with reasonable sensitivity and specificity. These methods have been applied to the detection of mutations in NSCLC by measuring the levels of circulating tumor DNA. ALK fusion genes along with mutations in EGFR and KRAS have been shown to correlate to tumor size and metastasis. These methods allow for noninvasive, affordable, and efficient diagnoses of oncogenic mutations that overcome the issues of traditional biopsies. These issues include tumor heterogeneity and early detection of cancers with asymptomatic early stages. Early detection and treatment remain the best way to ensure survival. This review aims to describe these new technologies along with their application in mutation detection in NSCLC in order to proactively utilize targeted anticancer therapy.

Circulating cell-free DNA as a prognostic and predictive biomarker in non-small cell lung cancer

Circulating cell-free DNA (cfDNA), which can be obtained from plasma or serum by non-invasive procedures, has showed great potential to predict treatment response and survival for cancer patients. Several studies have assessed the prognostic and predictive value of cfDNA in non-small cell lung cancer (NSCLC). However, these studies were often small and reported varying results. To address this issue, a meta-analysis was carried out. A total of 22 studies involving 2518 patients were subjected to the final analysis. Our results indicated that NSCLC patients with higher cfDNA concentration had shorter median progression-free survival (PFS) and overall survival (OS) time. In addition, high levels of cfDNA were significantly associated with poor PFS (hazard ratio or HR, 1.32; 95% CI, 1.02-1.71) and OS (HR, 1.64; 95% CI, 1.26-2.15). With respect to tumor specific mutations, we failed to reveal significant differences for PFS (HR, 1.30; 95% CI, 0.66-2.56) and OS (HR, 1.05; 95% CI, 0.49-2.25) when NSCLC patients were grouped according to KRAS genotype detected in cfDNA. However, NSCLC patients which harbored EGFR activating mutation in cfDNA had a greater chance of response to EGFR-TKIs (odds ratio or OR, 1.96; 95% CI, 1.59-2.42). No significant publication bias was detected in this study. In conclusion, cfDNA could act as a prognostic and predictive biomarker for patients with NSCLC.

Circulating cell-free DNA has a high degree of specificity to detect exon 19 deletions and the single-point substitution mutation L858R in non-small cell lung cancer

Detection of an epidermal growth factor receptor (EGFR) mutation in circulating cell-free DNA (cfDNA) is a noninvasive method to collect genetic information to guide treatment of lung cancer with tyrosine-kinase inhibitors (TKIs). However, the association between cfDNA and detection of EGFR mutations in tumor tissue remains unclear. Here, a meta-analysis was performed to determine whether cfDNA could serve as a substitute for tissue specimens for the detection of EGFR mutations. The pooled sensitivity, specificity, and areas under the curve of cfDNA were 0.60, 0.94, and 0.9208 for the detection of EGFR mutations, 0.64, 0.99, and 0.9583 for detection of the exon 19 deletion, and 0.57, 0.99, and 0.9605 for the detection of the L858R mutation, respectively. Our results showed that cfDNA has a high degree of specificity to detect exon 19 deletions and L858R mutation. Due to its high specificity and noninvasive characteristics, cfDNA analysis presents a promising method to screen for mutations in NSCLC and predict patient response to EGFR-TKI treatment, dynamically assess treatment outcome, and facilitate early detection of resistance mutations.

Use of SuperARMS EGFR Mutation Detection Kit to Detect EGFR in Plasma Cell-free DNA of Patients With Lung Adenocarcinoma

BACKGROUND

The SuperARMS EGFR Mutation Detection Kit (SuperARMS) is highly selective and sensitive and able to detect 41 of the most common somatic mutations in exons 18 to 21 of the epidermal growth factor receptor gene (EGFR). It allows for the detection of 0.2% to 0.8% mutant DNA in a background of 99.8% to 99.2% normal DNA. The present study assessed the performance of SuperARMS in detecting EGFR mutations in cell-free DNA (cfDNA) samples derived from plasma in patients with advanced lung adenocarcinoma.

MATERIALS AND METHODS

A total of 180 patients with advanced clinical stage lung adenocarcinoma were retrospectively registered. The concordance between the EGFR mutations detected by SuperARMS and ARMS (AmoyDx EGFR 29 Mutations Detection Kit) was analyzed.

RESULTS

Of the 180 samples, 57 (31.7%) were positive for EGFR mutations using SuperARMS, with 38 (21.1%) positive using ARMS. For the entire cohort, the positive, negative, and overall concordance rates were 97.3% (95% confidence interval [CI], 86.2%-99.5%), 85.3% (95% CI, 78.6%-90.2%), and 87.8% (95% CI, 82.2%-91.8%), respectively. The kappa value was 0.69 (95% CI, 0.57-0.81). For the 61 treatment-naive patients and 119 previously treated patients, the kappa values were 0.59 (95% CI, 0.37-0.79) and 0.74 (95% CI, 0.60-0.87), respectively. SuperARMS identified 9 samples harboring the T790M mutation; of these, only 1 (11.1%) was detected using ARMS.

CONCLUSION

SuperARMS is a promising plasma-based assay for EGFR mutations, including T790M. It might be useful in advanced-stage lung adenocarcinoma patients whose tissue biopsy samples are insufficient for a traditional diagnostic EGFR assay or for patients with a poor performance status.

Liquid biopsy genotyping in lung cancer: ready for clinical utility?

Liquid biopsy is a blood test that detects evidence of cancer cells or tumor DNA in the circulation. Despite complicated collection methods and the requirement for technique-dependent platforms, it has generated substantial interest due, in part, to its potential to detect driver oncogenes such as epidermal growth factor receptor (EGFR) mutants in lung cancer. This technology is advancing rapidly and is being incorporated into numerous EGFR tyrosine kinase inhibitor (EGFR-TKI) development programs. It appears ready for integration into clinical care. Recent studies have demonstrated that biological fluids such as saliva and urine can also be used for detecting EGFR mutant DNA through application other user-friendly techniques. This review focuses on the clinical application of liquid biopsies to lung cancer genotyping, including EGFR and other targets of genotype-directed therapy and compares multiple platforms used for liquid biopsy.

Can peripheral blood be used as surrogate in detecting epidermal growth factor receptor mutation status in advanced non-small cell lung cancer patients? A meta-analysis

Background

Apply peripheral blood as a surrogate for detecting epidermal growth factor receptor mutation status in tumor, also called liquid biopsy, has been reported to be a feasible method in patients with advanced non-small lung cancer. But the diagnostic yield varies in different studies.

Methods

A meta-analysis was carried out to evaluate the sensitivity and specificity of peripheral blood in detection epidermal growth factor receptor mutation status in advanced non-small lung cancer patients. Publications up to October 2016 were searched using PubMed, Embase and Web of Science databases. Sensitivity, specificity and other parameters were pooled using the bivariate mixed-effects regression model.

Results

Fifteen studies meeting the inclusion criteria were included. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 0.69 (95% CI: 0.59~0.78), 0.97 (95% CI: 0.94~0.99), 23.1 (95% CI: 11.6~46.1), 0.32 (95% CI: 0.23~0.44), 73 (95% CI: 33~159), respectively. The summary receiver operating characteristic curve was 0.93 (95% CI: 0.91–0.95).

Discussion

Detecting epidermal growth factor receptor mutation in peripheral blood is a reliable and non-invasive method in patients with advanced non-small lung cancer. More sensitive detection methods are required to increase the sensitivity of liquid biopsy of ctDNA.

Addition of bevacizumab for malignant pleural effusion as the manifestation of acquired EGFR-TKI resistance in NSCLC patients

This study aimed to investigate the role of bevacizumab in patients with advanced non-small cell lung cancer (NSCLC) who had developed acquired resistance to EGFR-TKIs therapy that manifested as malignant pleural effusion (MPE). In total, 86 patients were included. 47 patients received bevacizumab plus continued EGFR-TKIs and 39 patients received bevacizumab plus chemotherapy. The curative efficacy rate for MPE in bevacizumab plus EGFR-TKIs group was significantly higher than that in bevacizumab plus chemotherapy group (89.4% vs. 64.1%, respectively; P = 0.005). Patients in bevacizumab plus EGFR-TKIs group had longer progression-free survival (PFS) than those in bevacizumab plus chemotherapy group (median PFS 6.3 vs. 4.8 months, P = 0.042). While patients with acquired T790M mutation in bevacizumab plus EGFR-TKIs group had a significantly longer PFS than those in bevacizumab plus chemotherapy group (median PFS 6.9 vs. 4.6 months, P = 0.022), patients with negative T790M had similar PFS (median PFS 6.1 vs. 5.5 months, P = 0.588). Overall survival (OS) was similar between two groups (P = 0.480). In multivariate analysis, curative efficacy was an independent prognostic factor (HR 0.275, P = 0.047). In conclusion bevacizumab plus EGFR-TKIs could be a valuable treatment for NSCLC patients presenting with MPE upon resistant to EGFR-TKIs therapy, especially for those with acquired T790M mutation.

Clinical validation of a highly sensitive assay to detect EGFR mutations in plasma cell-free DNA from patients with advanced lung adenocarcinoma

BACKGROUND

Circulating tumor DNA (ctDNA) is a promising biomarker for noninvasive epidermal growth factor receptor (EGFR) mutations detection in lung cancer patients, but the existing methods have limitations in sensitivity or in availability. In this study, we evaluated the performance of a novel assay called ADx-SuperARMS in detecting EGFR mutations in plasma cell-free DNA from patients with advanced lung adenocarcinoma.

METHODS

A total of 109 patients with metastatic advanced adenocarcinoma were recruited who provided both blood samples and matched tumor tissue samples. EGFR mutation status in plasma samples were tested with ADx-SuperARMS EGFR assay and tumor tissue samples were tested with ADx-ARMS EGFR assay. The clinical sensitivity, specificity, positive prediction value (PPV), and negative prediction value (NPV) of ADx-SuperARMS EGFR assay were calculated by using EGFR mutation status in tumor tissue as standard reference. A receiver operating characteristic (ROC) analysis was implemented and an area under the curve (AUC) was calculated to evaluate sensitivity and specificity of exon 19 deletion (E19Del) and L858R mutation detection. The objective response rate (ORR) were calculated according to the EGFR mutation status determined by ADx-superARMS as well.

RESULTS

0.2% analytical sensitivity and 100% specificity of the ADx-SuperARMS EGFR assays for EGFR E19Del, L858R, and T790M mutants were confirmed by using a series of diluted cell line DNA. In the clinical study, EGFR mutations were detected in 45.9% (50/109) of the plasma samples and in 56.9% (62/109) of the matched tumor tissue samples. The sensitivity, specificity, PPV and NPV of the ADx-SuperARMS EGFR assay for plasma EGFR mutation detection were 82.0% (50/61), 100% (48/48), 100% (50/50), and 81.4% (48/59), respectively. In ROC analysis, ADx-SuperARMS achieved sensitivity and specificity of 88% and 99% in E19Dels as well as sensitivity and specificity of 89% and 100% in L858R, respectively. Among the 35 patients who were plasma EGFR mutation positive and treated with first generation of EGFR-tyrosine kinase inhibitors (TKIs), 23 (65.7%) achieved partial response, 11 (31.4%) sustained disease, and 1 (2.9%) progressive disease. The ORR and disease control rate (DCR) were 65.7% and 97.1%, respectively.

CONCLUSIONS

ADx-SuperARMS EGFR assay is likely to be a highly sensitive and specific method to noninvasively detect plasma EGFR mutations of patients with advanced lung adenocarcinoma. The EGFR mutations detected by ADx-SuperARMS EGFR assay could predict the efficacy of the treatment with first generation of EGFR-TKIs. Hence, EGFR blood testing with ADx-SuperARMS could address the unmet clinical needs.