Feasibility of re-biopsy and EGFR mutation analysis in patients with non-small cell lung cancer

Subregion-specific 18F-FDG PET-CT radiomics for the pre-treatment prediction of EGFR mutation status in solid lung adenocarcinoma

This study aimed to assess the efficacy of fluor-18 fluorodeoxyglucose (18F-FDG) PET/CT using sub-regional-based radiomics in predicting epidermal growth factor receptor (EGFR) mutation status in pretreatment patients with solid lung adenocarcinoma. A retrospective analysis included 269 patients (134 EGFR+ and 135 EGFR-) who underwent pretreatment 18F-FDG PET/CT scans and EGFR mutation testing. The most metabolically active intratumoral sub-region was identified, and radiomics features from whole tumors or sub-regional regions were used to build classification models. The dataset was split into a 7:3 ratio for training and independent testing. Feature subsets were determined by Pearson correlation and the Kruskal Wallis test and radiomics classifiers were built with support vector machines or logistic regressions. Evaluation metrics, including accuracy, area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were employed for different classifiers. Results indicated that the sub-region-based classifier outperformed the whole-tumor classifier in terms of accuracy (73.8% vs. 66.2%), AUC (0.768 vs. 0.632), specificity (65.0% vs. 50.0%), PPV (70.2% vs. 62.2%), and NPV (78.8% vs. 74.0%). The clinical classifier exhibited an accuracy of 75.0%, AUC of 0.768, sensitivity of 72.5%, specificity of 77.5%, PPV of 76.3%, and NPV of 73.8%. The combined classifier, incorporating sub-region analysis and clinical parameters, demonstrated further improvement with an accuracy of 77.5%, AUC of 0.807, sensitivity of 77.5%, specificity of 77.5%, and NPV of 77.5%. The study suggests that sub-region-based 18F-FDG PET/CT radiomics enhances EGFR mutation prediction in solid lung adenocarcinoma, providing a practical and cost-efficient alternative to invasive EGFR testing.

Usefulness of bronchial washing fluid for detection of EGFR mutations in non-small cell lung cancer

INTRODUCTION

The implementation of bronchial washing fluid (BWF) as a diagnostic specimen may complement the low diagnostic yields of plasma in detecting EGFR mutation (mEGFR) in non-small cell lung cancer. However, the diagnostic value of BWF in detecting mEGFR has yet to be clarified.

MATERIALS AND METHODS

From March 2021 to August 2022, patients with histologically confirmed NSCLC with matched tumor tissue, BWF, and/or plasma samples were enrolled. Patients were classified into either initial diagnosis or rebiopsy groups. Diagnostic yields of mEGFR in BWF and plasma were evaluated using droplet digital polymerase chain reaction and compared to mEGFR in tumor tissue as standard.

RESULTS

The study included 123 patients (74.1 %) in the initial diagnosis and 43 patients (25.9 %) in the rebiopsy group. BWF showed higher sensitivity, specificity, and concordance rates than plasma in both the initial diagnosis (57.4 %, 96.4 %, and 74.0 % vs. 16.4 %, 96.2 %, and 53.1 %) and the rebiopsy group (87.9 %, 60.0 %, and 81.4 % vs. 25.0 %, 75.0 %, and 41.7 %). In the initial diagnosis group, mEGFR was detected in the BWF of 13 out of 16 patients, even in the absence of tumor cells in the tissue biopsy. In these cases, EGFR test results obtained from BWF showed concordance with EGFR test results from the tumor tissue obtained through repeated biopsy or surgery later. In the rebiopsy group, T790M was detected in 16 patients (37.2 %) by tissue biopsy. The combined use of tissue biopsy and BWF increased detection, confirming T790M in 22 patients (51.2 %).

DISCUSSION

The detection of mEGFR using BWF shows higher diagnostic yields than plasma for both initial diagnosis and rebiopsy. T790M was detected earlier in BWF than in tissue rebiopsy in some cases, providing patients with an early opportunity to access third-generation EGFR-TKIs. The complementary use of BWF with tumor tissue may improve precision in EGFR-mutated NSCLC treatment strategies.

Sequential treatment in advanced epidermal growth factor receptor-mutated lung adenocarcinoma patients receiving first-line bevacizumab combined with 1st/2nd-generation EGFR-tyrosine kinase inhibitors

Introduction

The clinical outcomes of sequential treatment of advanced epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) patients with first-line bevacizumab combined with 1st/2nd-generation EGFR-TKIs are unclear. Thus, we aimed to analyze the outcomes of these patients.

Methods

Between January 2015 and December 2020, data for 102 advanced EGFR-mutated lung adenocarcinoma patients receiving first-line bevacizumab combined with erlotinib or afatinib followed by treatments at multiple institutions were retrospectively analyzed. All patients with progressive disease (PD) after first-line therapy underwent secondary T790M mutation detection.

Results

The secondary T790M mutation positive rate of all study patients was 57.9%. First-line erlotinib use and progression-free survival (PFS) after first-line therapy > 12 months were positively associated with the T790M mutation (P <0.05). The response rates (RRs) to second-line treatments were 51.7% and 22.7% for the osimertinib and nonosimertinib groups, respectively (P = 0.001). The median PFS associated with second-line osimertinib and nonosimertinib therapy was 13.7 and 7.1 months, respectively (hazard ratio (HR) = 0.38; 95% confidence interval (CI), 0.23-0.63; P< 0.001). Patients with a secondary T790M mutation receiving second-line osimertinib treatment had a median overall survival (OS) of 54.3 months, and the median OS was 31.9 months for non-T790M-mutated patients receiving second-line nonosimertinib treatments (HR = 0.36; CI: 0.21-0.62, P < 0.001).

Conclusion

The majority of acquired resistance to first-line bevacizumab combined with 1st/2nd-generation EGFR-TKIs is associated with the T790M mutation. Sequential osimertinib treatment in patients with positive secondary T790M mutation is associated with better outcomes among these patients.

Sequential treatment in advanced non-small cell lung cancer harboring EGFR mutations

BACKGROUND

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are standard treatments for advanced EGFR-mutated non-small cell lung cancer (NSCLC) patients. Osimertinib is an effective therapy for NSCLC patients with acquired resistance due to T790M mutation after first- and second-generation EGFR-TKI treatment. This study aimed to analyze the clinical outcomes of sequential therapy following first-line EGFR-TKIs and the predictive factors of an acquired T790M mutation.

METHODS

Between January 2014 and December 2018, data from 2190 advanced NSCLC patients with common EGFR mutations (exon 19 deletion and L858R) receiving first- and second-generation EGFR-TKIs in Linkou, Kaohsiung, Chiayi and Keelung Chang Gung Memorial Hospitals were retrospectively retrieved and analyzed.

RESULTS

Until August 2021, among 1943 patients who experienced progressive disease, 526 underwent T790M mutation tests, and their T790M-positive rate was 53.6%. Exon 19 deletion mutation and progression-free survival (PFS) of >12 months were positively associated with secondary T790M mutation. Different first-line first- and second-generation EGFR-TKI therapies did not affect the appearance of acquired T790M mutations. The median overall survival (OS) was 58.3 [95% confidence interval (CI): 49.0-67.5] months among the patients with T790M mutation who received second-line osimertinib therapy compared with 31.0 (95% CI: 27.5-34.5) months among the patients without T790M mutation who received chemotherapy alone. The multivariate analysis showed that a poor performance status (score: >2), nonadenocarcinoma histology, stage IV cancer, liver metastasis, brain metastasis, PFS while on first-line EGFR-TKIs, and subsequent chemotherapy without third-generation EGFR-TKIs were significant independent unfavorable prognostic factors for OS.

CONCLUSION

This study demonstrated the efficacy of first-line EGFR-TKIs and sequential osimertinib therapy. The results of our study suggest that T790M mutation tests are important for the use of subsequent osimertinib, which yielded favorable survival outcomes.

EGFR T790M testing through repeated liquid biopsy over time: a real-world multicentric retrospective experience

Background

About 15% of non-small cell lung cancers (NSCLCs) harbor epidermal growth factor receptor (EGFR) mutations. Upfront treatment with first and second generation EGFR tyrosine kinase inhibitors (1-2gen TKIs) is superior to chemotherapy. The most frequent resistance mechanism to 1-2gen TKIs is EGFR T790M mutation, which is targeted by osimertinib. T790M mutation can be revealed by liquid biopsy (LB) or by tissue rebiopsy (TB). LB is easily feasible but less sensitive than TB. We focused on repeated LBs and analyzed clinical features associated with EGFR T790M detection.

Methods

This is a retrospective multicenter observational study including EGFR-mutant NSCLC consecutive patients with disease progression (PD) after 1-2gen TKIs and with a first EGFR LB negative for T790M mutation, referred between 2016 and 2019. Aims of the study were to determine the prevalence of T790M mutation using LB in a real-life setting and the prevalence of T790M mutation by repeated LBs. We explored the association of T790M with clinical-pathological features and, through a survey, we evaluated the decision-making process behind LB request. Data on TBs were also collected.

Results

One hundred and ten patients were included in the study, for a total of 326 LBs. Median number of LB per patient was 3.0. The T790M prevalence through LB was 34.5%. Over time, significantly more LBs were requested "at clinical and radiological PD" and "at radiological PD" compared to "arbitrarily". The probability of finding the T790M mutation for a patient across each subsequent LB did not significantly change. Liver and lymph node PD were significantly correlated to T790M positivity. Notably, "at PD" compared to "arbitrarily" LB request and liver, bone or lymph node PD were correlated to the detection of any EGFR mutation in cfDNA. TB was performed in 59.7% of patients with a T790M negative LB and 18.8% of them were T790M positive. In most cases, TB was not feasible due to anatomical reasons. In our study population, the overall T790M prevalence-detected with both LB and TB-was 42.7%.

Conclusions

Repeated LB testing can be useful in a real-life scenario to detect EGFR T790M mutation.

A Real-World, Observational, Prospective Study to Assess the Molecular Epidemiology of Epidermal Growth Factor Receptor (EGFR) Mutations upon Progression on or after First-Line Therapy with a First- or Second-Generation EGFR Tyrosine Kinase Inhibitor in EGFR Mutation-Positive Locally Advanced or Metastatic Non-Small Cell Lung Cancer: The 'LUNGFUL' Study

Simple Summary

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer cases, with few patients carrying driver mutations in the gene encoding for epidermal growth factor receptor (EGFR). Advances in translational research have established EGFR tyrosine kinase inhibitors (TKIs) as the standard first-line therapy for NSCLC patients with activating EGFR mutations. The aim of our observational study was to assess the frequency of T790M acquired resistance and predictors of its presence, in patients with EGFR-mutated locally advanced or metastatic NSCLC who have progressed in the first-line EGFR-TKI treatment setting with first- or second-generation TKIs and have undergone molecular testing in tissue and/or plasma biopsy. The study highlights the challenges of performing tissue re-biopsy in routine care settings, which can lead to patients considered non-eligible for certain therapies from which they can benefit, and merits further actions from the healthcare community, in order to establish re-biopsy as a standard procedure.

Abstract

Background: Real-world data on the molecular epidemiology of EGFR resistance mutations at or after progression with first- or second-generation EGFR-TKIs in patients with advanced NSCLC are lacking. Methods: This ongoing observational study was carried out by 23 hospital-based physicians in Greece. The decision to perform cobas^®EGFR Mutation Test v2 in tissue and/or plasma at disease progression was made before enrollment. For patients with negative/inconclusive T790M plasma-based results, tissue re-biopsy could be performed. Results: Ninety-six (96) eligible patients were consecutively enrolled (median age: 67.8 years) between July-2017 and September-2019. Of the patients, 98% were tested upon progression using plasma and 2% using tissue/cytology biopsy. The T790M mutation was detected in 16.0% of liquid biopsies. Tissue re-biopsy was performed in 22.8% of patients with a T790M-negative plasma result. In total, the T790M positivity rate was 21.9%, not differing between patients on first- or second-generation EGFR-TKI. Higher (≥2) ECOG performance status and longer (≥10 months) time to disease progression following EGFR-TKI treatment initiation were associated with T790M positivity. Conclusions: Results from plasma/tissue-cytology samples in a real-world setting, yielded a T790M positivity rate lower than previous reports. Fewer than one in four patients with negative plasma-based testing underwent tissue re-biopsy, indicating the challenges in routine care settings.

Real-World Treatment Patterns, Epidermal Growth Factor Receptor (EGFR) Testing and Outcomes in EGFR-Mutated Advanced Non-small Cell Lung Cancer Patients in Belgium: Results from the REVEAL Study

BACKGROUND

Treatment of patients with epidermal growth factor receptor-mutated (EGFRm) non-small cell lung cancer (NSCLC) continues to evolve expeditiously.

OBJECTIVES

This retrospective study investigated real-world treatment patterns and EGFR mutation testing in patients with EGFRm advanced NSCLC in Belgium.

METHODS

Data were extracted from medical records of adults diagnosed with EGFRm locally advanced/metastatic NSCLC between 1 September 2015 and 31 December 2017. Patients were followed retrospectively from diagnosis until 1 September 2018, end of clinical activity or death. Data on demographics, patient outcomes and disease characteristics, treatment patterns and EGFR mutation testing at diagnosis and progression were analyzed descriptively.

RESULTS

A total of 141 patients were enrolled. At diagnosis, median age was 69 years, 63.1% were female, 88.7% had metastatic disease, 94.3% had adenocarcinoma histology, 76.6% had ECOG 0/1, 70.9% had common EGFR mutations and 29.1% had only rare mutations. In first line, 73.8% of patients received first/second-generation EGFR-tyrosine kinase inhibitors (1G/2G EGFR-TKIs), while 21.9% received other systemic treatments. Among 61 patients progressing on and discontinuing a first 1G/2G EGFR-TKI, 45 (73.8%) received subsequent systemic treatment while 16 (26.2%) did not; 20 (32.8%) received osimertinib. Among 65 patients progressing on a first 1G/2G EGFR-TKI, 47 (72.3%) were tested for T790M, of whom 25 (53.2%) were positive.

CONCLUSION

These real-world data from Belgium show that a substantial fraction of patients with EGFRm NSCLC do not receive 1G/2G EGFR-TKIs in first line and do not receive subsequent systemic treatment after progression on 1G/2G EGFR-TKIs. Only a third receive osimertinib upon progression on 1G/2G EGFR-TKIs. These observations should be considered in first-line treatment decisions.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03761901-December 3, 2018.

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.

Development of EGFR TKIs and Options to Manage Resistance of Third-Generation EGFR TKI Osimertinib: Conventional Ways and Immune Checkpoint Inhibitors

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have been first-line therapy in the treatment of non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutations. Progression inevitably happens after 10–14 months of first- or second-generation EGFR TKIs treatment for acquired resistance. Owing to the successful identification of EGFR T790M, third-generation EGFR TKIs such as osimertinib were developed to target such resistance mutation. Nowadays, osimertinib has shown its efficacy both in first-line and second-line after resistance to previous generations of TKI treatment of EGFR-mutant NSCLC. However, drug resistance also emerges on third-generation EGFR TKIs. Multiple mechanisms of acquired resistance have been identified, and some novel strategies were reported to overcome third-generation TKI resistance. Immune checkpoint inhibitors (ICIs) have dramatically changed the prognosis of selected patients. For patients with EGFR-addicted metastatic NSCLC, ICIs have also revealed a potential role. In this review, we will take stock of mechanisms of acquired resistance to third-generation TKIs and discuss current challenges and future perspectives in clinical practice.

Detection of epidermal growth factor receptor mutations in exhaled breath condensate using droplet digital polymerase chain reaction

The detection of certain oncogenic driver mutations, including those of epidermal growth factor receptor (EGFR), is essential for determining treatment strategies for advanced non-small cell lung cancer (NSCLC). The current study assessed the feasibility of testing exhaled breath condensate (EBC) for EGFR mutations by droplet digital PCR (ddPCR). Samples were collected from 12 patients with NSCLC harboring EGFR mutations that were admitted to Okayama University Hospital between June 1, 2014 and December 31, 2017. A total of 21 EBC samples were collected using the RTube™ method and EGFR mutations (L858R, exon 19 deletions or T790M) were assessed through ddPCR analysis (EBC-ddPCR). A total of 3 healthy volunteer samples were also tested to determine a threshold value for each mutation. Various patient characteristics were determined, including sex (3 males and 9 females), age (range 54-81 years; median, 66 years), smoking history (10 had never smoked; 2 were former smokers), histology (12 patients exhibited adenocarcinoma), clinical stage (9 patients were stage IV; 3 exhibited post-operative recurrence) and EGFR mutation type (4 had L858R; 8 had exon 19 deletions; 8 had T790M). EBC-ddPCR demonstrated positive droplets in 8 of the 12 patients. The sensitivity and specificity of each mutation was as follows: 27.3 and 80.0% for EGFR L858R, 30.0 and 90.9% for EGFR Ex19del, and 22.2 and 100% for EGFR T790M. EBC-ddPCR analysis of EGFR mutations exhibited modest sensitivity and acceptable specificity. EBC-ddPCR is a minimally invasive and replicable procedure and may be a complementary method for EGFR testing in patients where blood or tissue sampling proves difficult.

Influence of Biopsy Technique on Molecular Genetic Tumor Characterization in Non-Small Cell Lung Cancer-The Prospective, Randomized, Single-Blinded, Multicenter PROFILER Study Protocol

The detection of molecular alterations is crucial for the individualized treatment of advanced non-small cell lung cancer (NSCLC). Missing targetable alterations may have a major impact on patient's progression free and overall survival. Although laboratory testing for molecular alterations has continued to improve; little is known about how biopsy technique affects the detection rate of different mutations. In the retrospective study detection rate of epidermal growth factor (EGFR) mutations in tissue extracted by bronchoscopic cryobiopsy (CB was significantly higher compared to other standard biopsy techniques. This prospective, randomized, multicenter, single blinded study evaluates the accuracy of molecular genetic characterization of NSCLC for different cell sampling techniques. Key inclusion criteria are suspected lung cancer or the suspected relapse of known NSCLC that is bronchoscopically visible. Patients will be randomized, either to have a CB or a bronchoscopic forceps biopsy (FB). If indicated, a transbronchial needle aspiration (TBNA) of suspect lymph nodes will be performed. Blood liquid biopsy will be taken before tissue biopsy. The primary endpoint is the detection rate of molecular genetic alterations in NSCLC, using CB and FB. Secondary endpoints are differences in the combined detection of molecular genetic alterations between FB and CB, TBNA and liquid biopsy. This trial plans to recruit 540 patients, with 178 evaluable patients per study cohort. A histopathological and molecular genetic evaluation will be performed by the affiliated pathology departments of the national network for genomic medicine in lung cancer (nNGM), Germany. We will compare the diagnostic value of solid tumor tissue, lymph node cells and liquid biopsy for the molecular genetic characterization of NSCLC. This reflects a real world clinical setting, with potential direct impact on both treatment and survival.

EGFR mutation testing and treatment decisions in patients progressing on first- or second-generation epidermal growth factor receptor tyrosine kinase inhibitors

Background

The objective of this study was to investigate real-world EGFR mutation testing in patients with metastatic non-small cell lung cancer (NSCLC) upon progression on first−/second-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKI), and subsequent treatments received.

Methods

Flatiron Health electronic health records-derived database was used to identify adult patients with metastatic NSCLC treated with first−/second-generation EGFR-TKI from 11/2015–09/2017, with start of first EGFR-TKI defined as the index date. Patients were stratified by receipt of EGFR-TKI as first-line (1 L) or later-line (2 L+) treatment. Mutation testing and subsequent therapies following first−/second-generation EGFR-TKI were described.

Results

Overall, 782 patients (1 L = 435; 2 L+ =347) were included. Median age was 69.0 years, 63.6% were female, 56.3% were white, 87.1% were treated in community-based practices, and 30.1% of patients died during the study period; median follow-up was 309.0 days. Among the 294 (1 L = 160; 2L+ =134) patients who received subsequent therapies, treatments included chemotherapy only (1 L = 15.6%; 2L+ =21.6%), immunotherapy only (1 L = 13.8%; 2 L+ =41.0%), and targeted therapies (1 L = 70.0%; 2 L+ =36.6%). Specifically, 40 (25.0%) 1 L patients and 7 (5.2%) 2 L+ patients received osimertinib as subsequent therapy. Before the start of subsequent therapy, EGFR T790M resistance mutation testing was performed in 88 (29.9%) patients (1 L = 63 [39.4%]; 2 L+ =25 [18.7%]). Of these patients, 25 (28.4%) were T790M positive, among whom 24 (96.0%) received osimertinib.

Conclusions

A third of patients received subsequent therapies on disease progression; only 30% of these were tested for EGFR-TKI resistance mutation, prior to receiving subsequent therapies. These results highlight the importance of choosing treatments in the 1 L setting that optimize benefits for patients with EGFR-mutated NSCLC.

Detection of EGFR-Activating and T790M Mutations Using Liquid Biopsy in Patients With EGFR-Mutated Non-Small-Cell Lung Cancer Whose Disease Has Progressed During Treatment With First- and Second-Generation Tyrosine Kinase Inhibitors: A Multicenter Real-Life Retrospective Study

BACKGROUND

In advanced epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC) patients whose disease has progressed during treatment with first- and second-generation tyrosine kinase inhibitors (TKIs), liquid biopsy (LB) is routinely used to evaluate the presence of EGFR T790M as an acquired resistance mechanism. The objective of this study was to assess a real-life picture of EGFR T790M detection in LB.

MATERIALS AND METHODS

Liquid biopsies performed between June 2016 and October 2018 for advanced EGFR-mutated NSCLC at disease progression during treatment with first- and second-generation TKIs were retrospectively evaluated in 5 Italian centers. Circulating tumor DNA was extracted from plasma and tested with different commercial kits. The detection rate in LBs and the patients' characteristics were correlated.

RESULTS

We enrolled 120 consecutive patients. The overall T790M detection rate observed using LB was 25.8%. Fifty-four of 89 (60.7%) patients with negative LB results underwent tissue rebiopsy, and 56% were positive for T790M. The overall rate of T790M positivity in the study cohort was 49.2%. LB performed before formal tumor progression according to Response Evaluation Criteria In Solid Tumors criteria was negative for T790M in all patients (n = 21; P = .012). T790M positivity was statistically significantly higher in cases of disease progression at extrathoracic metastatic sites (P = .008) and, specifically, in the case of worsening bone disease (P = .003).

CONCLUSION

Our study shows that the detection of T790M-positive patients whose disease progressed during treatment with first- and second-generation TKIs in real life was according to the literature. However, this result was obtained with a specific clinical course (repeat LBs and tissue rebiopsy), thus implying the necessity for multidisciplinary management.

Molecular Analysis of Liquid-Based Cytological Specimen Using Virtually Positive Sputum with Adenocarcinoma Cells

Liquid-based cytology (LBC) analysis of sputum is a useful diagnostic and prognostic tool for detecting lung cancer. DNA and RNA derived from lung cancer cells can be used for this diagnosis. However, the quality of cytological material is not always adequate for molecular analysis due to the effect of formalin in the commercially available fixation kits. In this study, we examined DNA and RNA extraction methods for LBC analysis with formalin fixation, using lung carcinoma cell lines and sputum. The human non-small cell lung cancer cell lines were fixed with LBC fixation reagents, such as CytoRich red preservative. Quantification of thyroid transcription factor-1 (TTF-1) and actin mRNA, epidermal growth factor receptor (EGFR) DNA in HCC827, H1975, and H1299 cells, and mutation analysis of EGFR in HCC827 and H1975 cells were performed by quantitative PCR (qPCR) and fluorescence resonance energy transfer (FRET)-based preferential homoduplex formation assay (F-PHFA) method, respectively. mRNA and DNA extracted from cell lines using RNA and/or DNA extraction kits for formalin-fixed paraffin-embedded (FFPE) fixed with various LBC solutions were efficiently detected by qPCR. The detection limit of EGFR mutations was at a rate of 5% mutated positive cells in LBC. The detection limit of the EGFR exon 19 deletion in HCC827 was detected in more than 1.5% of the positive cells in sputum. In contrast, the detection limit of the T790M/L858R mutation in H1975 was detected in more than 13% of the positive cells. We also detected EGFR mutations using next generation sequencing (NGS). The detection limit of NGS for EGFR mutation was lower than that of the F-PHFA method. Furthermore, more than 0.1% of positive cells could be cytomorphologically detected. Our results demonstrate that LBC systems are powerful tools for cytopathological and genetic analyses. However, careful attention should be paid to the incidence of false negative results in the genetic analysis of EGFR mutations detected by LBC.

Biopsy on progression in patients with EGFR mutation-positive advanced non-small-cell lung cancer-a Canadian experience

Background

Epidermal growth factor receptor (egfr) tyrosine kinase inhibitors (tkis) are standard therapy for patients with advanced or metastatic non-small-cell lung cancer harbouring an EGFR mutation. Upon progression, 50%-60% develop a secondary T790M mutation. Recent trials demonstrated outcome improvement with osimertinib compared with standard platinum-based chemotherapy as second-line therapy for patients with secondary T790M mutation. To identify T790M, a biopsy of the tumour or, more recently, plasma is necessary. This retrospective study aimed to evaluate biopsy procedures and mutational analysis at 2 Canadian cancer centres.

Methods

In a retrospective review of patients who were approached to enrol in the aura2, aura3, or astris studies, demographics, eligibility for rebiopsy upon progression after an egfr tki, rebiopsy methods and complications, number of rebiopsies, and incidence of the T790M mutation were collected.

Results

Of 84 patients considered for trial enrolment, 80 signed a consent. In 78 patients who underwent rebiopsy, computed tomography or ultrasonography guidance were the most common methods used. The most common biopsy sites were lung and lymph nodes. The median number of rebiopsies performed to find a T790M mutation was 2. Only 9% of patients experienced complications. Of samples obtained, 74% were adequate for testing after initial rebiopsy. A T790M mutation was found in 47 patients, of whom 44 were enrolled on a trial. After multiple rebiopsies, only 5% of samples were inadequate for molecular analysis.

Conclusions

In the Canadian setting, the acceptance of rebiopsy on progression was high. Multiple rebiopsies were clinically feasible and could increase the yield for T790M mutation. The incidence of complications was low despite the most common site for rebiopsy being lung.

Be-TeaM: An Italian real-world observational study on second-line therapy for EGFR-mutated NSCLC patients

OBJECTIVES

Molecular diagnostics and care of non-small cell lung cancer (NSCLC) are continuously evolving. Few data document the current strategies to manage advanced NSCLC patients beyond progression in clinical practice.

PATIENTS AND METHODS

Be-TeaM is an Italian multi-center observational study conducted on consecutive EGFR-mutated stage IV NSCLC patients, progressed during/after a first-line EGFR-TKI. It consists of a retrospective phase, from first-line EGFR-TKI therapy start until study entry (i.e. beginning of the diagnostic process), and a prospective phase, until treatment choice or for 3 months if no therapy was prescribed. Primary objective was to describe the diagnostic and therapeutic approaches adopted after progression in a real-world setting.

RESULTS

Of 308 patients enrolled in 63 centers from July 2017 to June 2018, 289 were included in the analysis. In first line, 53.3 % received gefitinib, 32.5 % afatinib and 14.2 % erlotinib. The testing rate (i.e. rate of all patients undergone any biopsy -liquid and/or tissue- for the T790 M detection) was 90.7 %, with liquid biopsy being the most frequently executed. Of 262 biopsied patients, 64.5 % underwent only 1 liquid biopsy, 10.7 % only 1 tissue biopsy and 18.3 % >1 biopsy, both liquid and solid in 85.4 %. The T790M positivity rate was 45.3 %; of 166 patients undergone only a liquid biopsy and tested for the mutation, 39.8 % were T790M+ and 60.2 % T790M-/undetermined. By the observation end, 87.9 % patients had a post-progression treatment chosen, osimertinib being the most frequent among the T790M+.

CONCLUSION

Be-TeaM provides the first snapshot of current practices for the management of NSCLC patients beyond progression in Italy; in clinical practice, assessing the T790M status is not always feasible.

Value of pre-therapy 18F-FDG PET/CT radiomics in predicting EGFR mutation status in patients with non-small cell lung cancer

PURPOSE

To assess the predictive power of pre-therapy ¹⁸F-FDG PET/CT-based radiomic features for epidermal growth factor receptor (EGFR) mutation status in non-small cell lung cancer.

METHODS

Two hundred and forty-eight lung cancer patients underwent pre-therapy diagnostic ¹⁸F-FDG PET/CT scans and were tested for genetic mutations. The LIFEx package was used to extract 47 PET and 45 CT radiomic features reflecting tumor heterogeneity and phenotype. The least absolute shrinkage and selection operator (LASSO) algorithm was used to select radiomic features and develop a radiomics signature. We compared the predictive performance of models established by radiomics signature, clinical variables, and their combinations using receiver operating curves (ROCs). In addition, a nomogram based on the radiomics signature score (rad-score) and clinical variables was developed.

RESULTS

The patients were divided into a training set (n = 175) and a validation set (n = 73). Ten radiomic features were selected to build the radiomics signature model. The model showed a significant ability to discriminate between EGFR mutation and EGFR wild type, with area under the ROC curve (AUC) equal to 0.79 in the training set, and 0.85 in the validation set, compared with 0.75 and 0.69 for the clinical model. When clinical variables and radiomics signature were combined, the AUC increased to 0.86 (95% CI [0.80-0.91]) in the training set and 0.87 (95% CI [0.79-0.95]) in the validation set, thus showing better performance in the prediction of EGFR mutations.

CONCLUSION

The PET/CT-based radiomic features showed good performance in predicting EGFR mutation in non-small cell lung cancer, providing a useful method for the choice of targeted therapy in a clinical setting.

Toward automatic prediction of EGFR mutation status in pulmonary adenocarcinoma with 3D deep learning

To develop a deep learning system based on 3D convolutional neural networks (CNNs), and to automatically predict EGFR‐mutant pulmonary adenocarcinoma in CT images. A dataset of 579 nodules with EGFR mutation status labels of mutant (Mut) or wild‐type (WT) was retrospectively analyzed. A deep learning system, namely 3D DenseNets, was developed to process 3D patches of nodules from CT data, and learn strong representations with supervised end‐to‐end training. The 3D DenseNets were trained with a training subset of 348 nodules and tuned with a development subset of 116 nodules. A strong data augmentation technique, mixup, was used for better generalization. We evaluated our model on a holdout subset of 115 nodules. An independent public dataset of 37 nodules from the cancer imaging archive (TCIA) was also used to test the generalization of our method. Conventional radiomics analysis was also performed for comparison. Our method achieved promising performance on predicting EGFR mutation status, with AUCs of 75.8% and 75.0% for our holdout test set and public test set, respectively. Moreover, strong relations were found between deep learning feature and conventional radiomics, while deep learning worked through an enhanced radiomics manner, that is, deep learned radiomics (DLR), in terms of robustness, compactness and expressiveness. The proposed deep learning system predicts EGFR‐mutant of lung adenocarcinomas in CT images noninvasively and automatically, indicating its potential to help clinical decision‐making by identifying eligible patients of pulmonary adenocarcinoma for EGFR‐targeted therapy.

Strategies to overcome acquired resistance to EGFR TKI in the treatment of non-small cell lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) represents a paradigm shift in the treatment of non-small cell lung cancer (NSCLC) patients and has been the first-line therapy in clinical practice. While erlotinib, gefitinib and afatinib have achieved superior efficacy in terms of progression-free survival and overall survival compared with conventional chemotherapy in NSCLC patients, most people inevitably develop acquired resistance to them, which presents another challenge in the treatment of NSCLC. The mechanisms of acquired resistance can be classified as three types: target gene mutation, bypass signaling pathway activation and histological transformation. And the most common mechanism is T790M which accounts for approximately 50% of all subtypes. Many strategies have been explored to overcome the acquired resistance to EGFR TKI. Continuation of EGFR TKI beyond progressive disease is confined to patients in asymptomatic stage when the EGFR addiction is still preserved in some subclones. While the combination of EGFR TKI and chemotherapy or other targeted agents has improved the survival benefit in EGFR TKI resistant patients, there are controversies within them. The next-generation EGFR TKI and immunotherapy represent two novel directions for overcoming acquired resistance and have achieved promising efficacy. Liquid biopsy provides surveillance of the EGFR mutation by disclosing the entire genetic landscape but tissue biopsy is still indispensable because of the considerable rate of false-negative plasma.

Repeat biopsy procedures and T790M rates after afatinib, gefitinib, or erlotinib therapy in patients with lung cancer

OBJECTIVES

Afatinib, a second-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is used for EGFR-mutant non-small cell lung cancer (NSCLC). However, there are few reports about its resistance mechanisms. The aims of this study are to evaluate resistance mechanisms of afatinib compared with other TKIs and analyze the performance of repeat biopsy which is critical for subsequent treatment.

MATERIALS AND METHODS

We screened EGFR-mutant NSCLC patients who started first-line afatinib, gefitinib, or erlotinib from 2014 to 2016, and included patients who acquired resistance. Among those patients, T790 M mutation rates and histologic transformation were compared as an acquired resistance mechanism.

RESULTS

A total of 524 patients started EGFR-TKIs, and 347 experienced disease progression until April 2018. After excluding nine patients with de novo T790 M mutations or who were treated with two TKIs before repeat biopsy, 338 patients were included. Among these patients, 263 (78%) were successfully biopsied and evaluated for EGFR mutations and histologic transformation. T790 M mutation was documented in 35 (41%) of 86 evaluable patients in afatinib group, which is significantly lower than in gefitinib (55%, 73/133) and erlotinib groups (57%, 25/44) (p =  0.026). In multivariate analysis considering both baseline EGFR mutation types (deletion 19 or L858R) and sex, the odds ratio for T790M in afatinib group was 0.45 (95% confidence interval: 0.254-0.795, p =  0.006), compared with gefitinib or erlotinib groups. Five histologic transformations (two small cell, three squamous cell) were detected in afatinib group, while one small cell transformation was detected in gefitinib group, and no transformations were detected in erlotinib group.

CONCLUSIONS

In our clinical practice, repeat biopsy was possible in nearly four of five patients. Although T790 M mutation appears to be the main resistance mechanism for afatinib, it affects a lower proportion of patients than observed with first-generation TKIs.