Mutation abundance affects the therapeutic efficacy of EGFR-TKI in patients with advanced lung adenocarcinoma: A retrospective analysis

Presence of liver metastasis correlated with high tumor abundance and indicated adverse prognostic feature in EGFR mutation non-small-cell lung cancer patients

EGFR-TKIs are effective therapies for non-small cell lung cancer (NSCLC) patients with EGFR-activating mutations. However, responses vary within individuals and resistant disease inevitably emerges. A prospective cohort of 130 patients with advanced EGFR mutation NSCLC were enrolled. Pre-and post-treatment plasma from subjects treated with EGFR-TKIs were obtained. The correlation between EGFR mutation abundance using the Idylla™ ctEGFR mutation assay, radiographic assessment, and clinical outcomes were analyzed. Eighty-nine patients with retrieved blood collection were analyzed. Undetectable ctEGFR (49.5%), detectable ctEGFR CqMut-high (23.5%), and detectable ctEGFR CqMut low (27%) using CqMut cutoff at 28.1, represented consecutive incremental tumor burden by radiographic assessment and outcome of treatment. Median PFS was 13.4 months [95% CI 12.0-14.8] in undetectable ctEGFR, 10.4 months [95% CI 9.9-10.9] in ctEGFR CqMut-high, and 5.9 months [95% CI 3.8-7.4] in ctEGFR CqMut-low. Number of metastasis sites > 3 was found in 22.7%, 23.8%, and 58.3% of the 3-tier ctEGFR tumor burden levels, respectively (p-value 0.01). Presence of liver metastasis was significantly correlated with number of metastasis sites > 3 and ctEGFR CqMut-low (45.8%). Liver metastasis was an independent factor of reduced PFS and OS by multivariate analysis with an HR = 2.41 [95% CI 1.27-4.60, p-value 0.007]) and HR = 2.96 [95% CI 1.35-6.51, p-value 0.007], respectively. The pretreatment ctEGFR detection using the Idylla™ ctEGFR mutation assay served as a surrogate marker for tumor abundance and tumor burden. Presence of liver metastasis was found to be a clinical predictor associated with high tumor abundance and worsening treatment outcomes.

A Comprehensive Review of Epidermal Growth Factor Receptor Mutation Abundance in Non-Small Cell Lung Cancer Treated with Tyrosine Kinase Inhibitors

BACKGROUND

Lung cancer is a major contributor to cancer-related death worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are currently viewed as the established first-line therapy for patients with advanced NSCLC with EGFR mutations.

SUMMARY

The potential predictive value of the quantitative abundance of epidermal growth factor receptor (EGFR) mutations in the treatment of NSCLC is widely recognized and regarded as a significant indicator. The definition of mutation abundance in the EGFR gene in most current studies is mainly calculated based on the ratio of mutation to wild-type gene copy number or based on the ratio of allele number; for example, variant allele frequency is the ratio of the number of mutant alleles to the total number of alleles at a particular locus. Results of the included primary studies are as follows. (1) Significant association between EGFR mutation abundance and progression-free survival (PFS): median PFS was significantly longer in the high abundance group (11.0 months, 95% CI: 9.7-12.3 months) than in the low abundance group (5.3 months, 95% CI: 3.6-7.0 months) in the study by Liu et al. High mutation abundance (HR: 0.77, 95% CI: 0.66-0.82, p = 0.037) was an independent prognostic determinant of PFS in the study by Wang et al. Among patients receiving EGFR-TKI as first-line therapy, the median PFS was significantly longer in the high mutation abundance group than in the low mutation abundance group (12.7 months vs. 8.7 months, p = 0.002). EGFR mutation abundance ≥30% was an independent risk factor for PFS (HR: 1.64, 95% CI: 1.17-2.31). (2) Significant association between EGFR mutation abundance and overall survival (OS): the median OS in the high abundance group in the study by Liu et al. was 20.9 months (95% CI: 18.3-23.5 months), while that in the low abundance group was 13.0 months (95% CI: 10.0 months) (95% CI: 10.3-15.7 months); longer OS was independently associated with high mutation abundance (HR: 0.62, 95% CI: 0.50-0.79, p = 0.027).

KEY MESSAGES

The objective of this article was to conduct a comprehensive examination and analysis of the association between the abundance of EGFR mutations in NSCLC and the effectiveness of treatment with TKIs while also considering the development of drug resistance.

Variant allele frequency: a decision-making tool in precision oncology?

Precision oncology requires additional predictive biomarkers for targeted therapy selection. Variant allele frequency (VAF), measuring the proportion of variant alleles within a genomic locus, provides insights into tumor clonality in somatic genomic testing, yielding a strong rationale for targeting dominant cancer cell populations. The prognostic and predictive roles of VAF have been evaluated across different studies. Yet, the absence of validated VAF thresholds and a lack of standardization between sequencing assays currently hampers its clinical utility. Therefore, analytical and clinical validation must be further examined. This Review summarizes the evidence regarding the use of VAF as a predictive biomarker and discusses challenges and opportunities for its clinical implementation as a decision-making tool for targeted therapy selection.

Clinical Pathological Characteristics and Prognosis of Multigene Co-Mutations in Elderly Patients With Non-Small Cell Lung Cancer: A Retrospective Analysis

Background

With the development and wide application of next-generation sequencing (NGS), multiple-gene mutations related to lung cancer are detected using this technology. Notably, even multigene concomitant mutations (co-mutations), which occur at a relatively low incidence, can be detected more effectively using NGS. It is well-known that the percentages of non-small cell lung cancer (NSCLC) in the elderly lung cancer population are also gradually increasing, while its prognosis is hard and the quality of long-term survival is poor. This study aimed at investigating the common clinicopathologic features of multigene co-mutations for better evaluating the prognosis of elderly NSCLC patients.

Methods

A total of 464 NSCLC patients were divided into 3 groups according to the types of gene mutation, whose clinical data were retrospectively analyzed.

Results

In total, 38.36% (178/464) of NSCLC patients were in the nonmutation group, 50% in the single-gene mutation group, and 11.64% in the multigene co-mutation group. Nonmutation, single-gene mutation, and co-mutation groups were all prone to occur in male adenocarcinoma patients (P < .05). EGFR gene mutation rates were the highest in the single-gene mutation and co-mutation groups (54.31% and 24.35%). In the co-mutation group, the incidence of EGFR/PIK3CA, LK/KRAS, and EGFR/MET co-mutations was the highest (16.67%, 11.11%, and 7.41%). ALK/HER2/MET, EGFR/HER2/MET, and EGFR/HER2/MET/ROS1 multiple-gene co-mutations were, respectively, found in 1 case, and the multigene co-mutation patients commonly had a worse median progression-free survival (PFS) than that of single-gene mutation (7.13 vs 12.34 months, P = .013).

Conclusion

With the application of NGS, the detectable rates of gene co-mutation are increasingly high in elderly patients with NSCLC, which mainly occurs in male adenocarcinoma patients commonly with poor PFS. It will be critically necessary to conduct multigene detections by NGS for directing targeted therapy of elderly NSCLC patients.

Concordance of Abundance for Mutational EGFR and Co-Mutational TP53 with Efficacy of EGFR-TKI Treatment in Metastatic Patients with Non-Small-Cell Lung Cancer

The present study aimed to investigate the influence of the mutation abundance of the epidermal growth factor receptor (EGFR) and its co-mutation with TP53 on the therapeutic efficacy of tyrosine kinase inhibitor (TKI) treatment in patients with metastatic lung adenocarcinoma (LUAD). In total, 130 patients (January 2018-September 2022) with metastatic LUAD from the Second Affiliated Hospital of Zhejiang University were included. Kaplan-Meier analysis was performed to measure the duration of drug application (DDA) and the log-rank test was used to compare differences. Univariate and multivariate analyses of Cox proportional hazard regression models were used to evaluate the association between the relevant clinicopathological factors and DDA. Hazard ratios with 95% confidence intervals were also calculated. Among the 130 patients who were treated with first-generation EGFR-TKIs, 86 showed high-EGFR mutation abundance (>22.0%) and 44 showed low-EGFR mutation abundance (≤22.0%). Patients in the high-EGFR group had a greater DDA than those in the low-EGFR group (p < 0.05). The results of the subgroup analysis were consistent with those of the total mutation population (exon19: >18.5% vs. ≤18.5%, 14 months vs. 10 months, p = 0.049; exon21: >22.0% vs. ≤22.0%, 15 months vs. 9 months, p = 0.005). In addition, the mutation abundance of TP53 was negatively correlated with the DDA (p < 0.05). Patients in the combination group had a better DDA than those in the monotherapy group (p < 0.05). Subgroup analysis showed that, among the low mutation abundance of the EGFR exon 21 or 19 cohort, the combination group had a better DDA than the monotherapy group (p < 0.05). An EGFR mutation abundance greater than 22.0% was a positive predictor of DDA in patients with metastatic LUAD. However, a TP53 mutation abundance higher than 32.5% could reverse this situation. Finally, first-line treatment with EGFR-TKIs plus chemotherapy is a potential treatment strategy for patients with low-abundance EGFR mutations.

Mutation status analysis of 58 patients with advanced ALK fusion gene positive non small cell lung cancer

PURPOSE

To analyze the characteristics and prognostic values of Anaplastic Lymphoma Kinase (ALK) fusion gene partner, gene subtype and abundance in tumor tissues of advanced Non Small Cell Lung Cancer (NSCLC) patients with positive ALK fusion gene and to explore the best treatment mode of ALK-Tyrosine Kinase Inhibitors(TKIs).

METHODS

Cases of advanced NSCLC patients with ALK positive confirmed by both Next Generation Sequencing (NGS) and immunohistochemistry were retrospectively collected. The relationships of Overall Survival (OS)/Progression Free Survival (PFS) between different mutation subtypes, mutation abundance, clinicopathological features were analyzed. OS/PFS between different treatment mode of ALK inhibitors were compared.

RESULTS

Fifty-eight patients were enrolled. There were diverse fusion partners. Five subtypes of Echinoderm Microtubule-associated protein-Like 4 gene (EML4)-ALK fusion mutation were detected: V1,V2,V3,V5 and V7. The mutation abundance ranged from 0.13 to 27.77%, with a median of 5.34%. The abundance of V2 and V5 was higher than V1 and V3 respectively. There was no difference in OS between the low abundance group(≤ 5.34%) and the high abundance group(>5.34%) (P = 0.434). PFS of second-generation ALK inhibitors as first-line treatment was longer than that of Crizotinib as first-line (P<0.001). Never smokers had longer OS than current smokers(P = 0.001).

CONCLUSIONS

There are differences in abundance between different fusion partners and subtypes in advanced NSCLC with positive ALK. OS is not associated with subtypes, mutation abundance and first line treatment option of either generation of ALK inhibitors. Smoking is a poor prognostic factor.

Treatment of advanced non-small cell lung cancer with driver mutations: current applications and future directions

With the improved understanding of driver mutations in non-small cell lung cancer (NSCLC), expanding the targeted therapeutic options improved the survival and safety. However, responses to these agents are commonly temporary and incomplete. Moreover, even patients with the same oncogenic driver gene can respond diversely to the same agent. Furthermore, the therapeutic role of immune-checkpoint inhibitors (ICIs) in oncogene-driven NSCLC remains unclear. Therefore, this review aimed to classify the management of NSCLC with driver mutations based on the gene subtype, concomitant mutation, and dynamic alternation. Then, we provide an overview of the resistant mechanism of target therapy occurring in targeted alternations ("target-dependent resistance") and in the parallel and downstream pathways ("target-independent resistance"). Thirdly, we discuss the effectiveness of ICIs for NSCLC with driver mutations and the combined therapeutic approaches that might reverse the immunosuppressive tumor immune microenvironment. Finally, we listed the emerging treatment strategies for the new oncogenic alternations, and proposed the perspective of NSCLC with driver mutations. This review will guide clinicians to design tailored treatments for NSCLC with driver mutations.

Can Liquid Biopsy Based on ctDNA/cfDNA Replace Tissue Biopsy for the Precision Treatment of EGFR-Mutated NSCLC?

More and more clinical trials have explored the role of liquid biopsy in the diagnosis and treatment of EGFR-mutated NSCLC. In certain circumstances, liquid biopsy has unique advantages and offers a new way to detect therapeutic targets, analyze drug resistance mechanisms in advanced patients, and monitor MRD in patients with operable NSCLC. Although its potential cannot be ignored, more evidence is needed to support the transition from the research stage to clinical application. We reviewed the latest progress in research on the efficacy and resistance mechanisms of targeted therapy for advanced NSCLC patients with plasma ctDNA EGFR mutation and the evaluation of MRD based on ctDNA detection in perioperative and follow-up monitoring.

Evaluate the Prognosis of MYC/TP53 Comutation in Chinese Patients with EGFR-Positive Advanced NSCLC Using Next-Generation Sequencing: A Retrospective Study

Purpose: The purpose of this study was to investigate the effect of MYC and TP53 comutations on the clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) in Chinese patients with advanced EGFR-positive nonsmall-cell lung cancer (NSCLC). Patients and methods: Tissue samples and information from 65 patients with advanced NSCLC in Northern Jiangsu People's Hospital were collected and analyzed by next-generation sequencing (NGS). Progression-free survival (PFS) and total survival (OS) were the main endpoints, and the objective response rate (ORR) and disease control rate (DCR) were the secondary endpoints. Result: Among 65 patients, 17 had TP53 and MYC wild-type mutations (WT/WT), 36 had TP53 mutant and MYC wild-type mutations (TP53/WT), and 12 had coexisting MYC/TP53 mutations (MYC/TP53). When 12 patients with MYC/TP53 comutation were compared with the other two groups (TP53/WT, WT/WT), mPFS and mOS are significantly lower than those in the other two groups (mPFS: 4.1 months vs 6.0 months, 12.3 months, HR: 0.769, 95% CI: 4.592-7.608, P  =  .047. mOS: 14.6 months vs 24.1 months, 31.5 months, HR: 3.170, 95% CI: 18.786-31.214, P < .001), and the ORR, DCR of patients with MYC/TP53 comutation was lower than that of the other two groups (ORR, 25% vs 44.4%, 70.6%, P  =  .045. DCR, 58.3% vs 72.2%, 82.4%, P  =  .365). Conclusion: Patients with MYC/TP53 comutations with EGFR-positive advanced NSCLC are more likely to develop drug resistance after early treatment with EGFR-TKIs and have a worse clinical outcome.

18F-Fluorodeoxyglucose PET/CT for Early Prediction of Outcomes in Patients with Advanced Lung Adenocarcinomas and EGFR Mutations Treated with First-Line EGFR-TKIs

Simple Summary

Epithelial growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are the first-line therapy for patients with advanced-stage lung adenocarcinoma with EGFR mutations. However, 17–31% of these patients do not respond to therapy, making early evaluation of treatment response crucial. This prospective study investigates the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for timely prediction of response and survival of these patients. We evaluated 30 patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations, receiving first-line EGFR-TKI therapy. ¹⁸F-FDG PET/CT was performed before and two weeks after initiation of treatment. Positron Emission Tomography Response Criteria in Solid Tumors served as an independent predictor of non-progressive disease; baseline and change of metabolic tumor volume represented independent predictors of progression-free survival and overall survival, respectively. Therefore, ¹⁸F-FDG PET/CT is an early predictor of outcomes and individual prognosis of patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKI therapy.

Abstract

This study aims to investigate the role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in early prediction of response and survival following epithelial growth factor receptor (EGFR)–tyrosine kinase inhibitor (TKI) therapy in patients with advanced lung adenocarcinomas and EGFR mutations. Thirty patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKIs were prospectively evaluated between November 2012 and May 2015. EGFR mutations were quantified by delta cycle threshold (dCt). ¹⁸F-FDG PET/CT was performed before and 2 weeks after treatment initiation. PET response was assessed based on PET Response Criteria in Solid Tumors (PERCIST). Baseline and percentage changes in the summed standardized uptake value, metabolic tumor volume (bsumMTV and ΔsumMTV, respectively), and total lesion glycolysis of ≤5 target lesions/patient were calculated. The association between parameters (clinical and PET) and non-progression disease after 3 months of treatment in CT based on the Response Evaluation Criteria in Solid Tumors Version 1.1 (nPD_3mo), progression-free survival (PFS), and overall survival (OS) were tested. The median follow-up time was 19.6 months. The median PFS and OS were 12.0 and 25.3 months, respectively. The PERCIST criteria was an independent predictor of nPD_3mo (p = 0.009), dCt (p = 0.014) and bsumMTV (p = 0.014) were independent predictors of PFS, and dCt (p = 0.014) and ΔsumMTV (p = 0.005) were independent predictors of OS. ¹⁸F-FDG PET/CT achieved early prediction of outcomes in patients with advanced lung adenocarcinomas and EGFR mutations receiving EGFR-TKIs.

Novel MRPS9-ALK Fusion Mutation in a Lung Adenocarcinoma Patient: A Case Report

Anaplastic lymphoma kinase (ALK) rearrangements account for approximately 5-6% of non-small-cell lung cancer (NSCLC) patients. In this study, a case of lung adenocarcinoma harboring a novel MRPS9-ALK fusion is reported. The patient responded well to the first and second generation of ALK-tyrosine kinase inhibitors (ALK-TKIs) (crizotinib then alectinib), as her imaging findings and clinical symptoms significantly improved. At last follow-up, over 21 months of overall survival (OS) has been achieved since ALK-TKI treatment. The progression-free survival (PFS) is already ten months since alectinib. The adverse effects were manageable. The case presented here provides first clinical evidence of the efficacy of ALK-TKIs in NSCLC patients with MRPS9-ALK fusion.

Plasma EGFR mutation abundance affects clinical response to first-line EGFR-TKIs in patients with advanced non-small cell lung cancer

Background

Activated epidermal growth factor receptor (EGFR) mutation is the main pathogenic cause of non-small cell lung cancer (NSCLC) in Asia. However, the impact of plasma EGFR mutation abundance, especially of the ultra-low abundance of EGFR mutation detected by highly sensitive techniques on clinical outcomes of first-line EGFR tyrosine kinase inhibitors (TKIs) for advanced NSCLC patients remains unclear.

Methods

We qualitatively detected baseline EGFR status of NSCLC tissues using amplification-refractory mutation system and quantified the plasma abundance of EGFR mutations through next-generation sequencing (NGS). Every 8–12 weeks, we performed dynamic detection of plasma mutation abundance and imaging evaluation. We analyzed the association between plasma abundance of EGFR sensitizing mutations, tumor size, tumor shrinkage percentage, concomitant TP53 mutations, and clinical response to TKIs.

Results

This prospective study enrolled 135 patients with advanced NSCLC. The objective response rate (ORR) and disease control rate (DCR) for EGFR mutation–positive patients were 50.0% and 87.0%, respectively. When the cutoff value of plasma EGFR mutation abundance was 0.1%, the ORRs of TKI-treated patients were significantly different (60.0% for the >0.1% group vs. 21.4% for the ≤0.1% group, P=0.028). Median progression-free survival (PFS) was significantly longer for participants with a mutation abundance above 0.1% compared to those with a 0.01–0.1% abundance (log rank, P=0.0115). There was no significant association between plasma abundance of EGFR sensitizing mutations and tumor size, tumor shrinkage percentage, or concomitant TP53 mutations. Cox multivariate analysis demonstrated that plasma mutation abundance was an independent predictive factor for PFS [hazard ratio (HR) 2.41, 95% confidence interval (CI): 1.12–5.20; P=0.025]. We identified 11 participants with the acquired T790M resistance mutation according to serial dynamic plasma samples.

Conclusions

Liquid biopsy screening based on highly sensitive NGS is reliable for detecting drug resistance and actionable somatic mutations. The plasma abundance of the EGFR driver mutation affected clinical response to EGFR-TKIs in advanced NSCLC patients; prolongation of PFS was also observed in patients with an ultra-low abundance of EGFR sensitizing mutations.

EGFR variant allele frequency predicts EGFR-TKI efficacy in lung adenocarcinoma: a multicenter study

Background

Although lung adenocarcinoma (LADC) with sensitizing mutations of the epidermal growth factor receptor (EGFR) is highly sensitive to EGFR tyrosine kinase inhibitors (EGFR-TKIs), in most cases disease progression inevitably occurs. Our aim was to investigate the predictive and prognostic significance of adjusted tumoral EGFR variant allele frequency (EGFR-aVAF) in the above setting.

Methods

Eighty-nine Caucasian advanced-stage LADC patients with known exon-specific EGFR mutations undergoing EGFR-TKI treatment were included. The correlations of EGFR-aVAF with clinicopathological variables including progression-free and overall survival (PFS and OS, respectively) were retrospectively analyzed.

Results

Of 89 EGFR-mutant LADC patients, 46 (51.7%) had exon 19 deletion, while 41 (46.1%) and 2 (2.2%) patients had exon 21- and exon 18-point mutations, respectively. Tumoral EGFR-aVAF was significantly higher in patients harboring EGFR exon 19 mutations than in those with exon 21-mutant tumors (P<0.001). Notably, patients with EGFR exon 19 mutant tumors demonstrated significantly improved PFS (P=0.003) and OS (P=0.02) compared to patients with exon 21 mutations. Irrespective of specific exon mutations, a statistically significant positive linear correlation was found between EGFR-aVAF of tumoral tissue and PFS (r=0.319; P=0.002). High (≥70%) EGFR-aVAF was an independent predictor of longer PFS [vs. low (<70%) EGFR-aVAF; median PFSs were 52 vs. 26 weeks, respectively; P<0.001]. Additionally, patients with high EGFR-aVAF also had significantly improved OS than those with low EGFR-aVAF (P=0.011).

Conclusions

Our study suggests that high (≥70%) EGFR-aVAF of tumoral tissue predicts benefit from EGFR-TKI treatment in advanced LADC and, moreover, that exon 19 EGFR mutation is associated with high EGFR-aVAF and improved survival outcomes.

Durable Complete Response to Alectinib in a Lung Adenocarcinoma Patient With Brain Metastases and Low-Abundance EML4-ALK Variant in Liquid Biopsy: A Case Report

EML4-ALK fusions are targetable oncogenic drivers in a subset of advanced non-small cell lung cancer (NSCLC) patients that can benefit from selected ALK inhibitors. Precise detection of ALK fusions may yield critical information for selection of appropriate therapy and hence improve patient survival. Analysis of circulating tumor DNA (ctDNA) in liquid biopsies using next generation sequencing (NGS) prior to or during treatment hold great promise for disease monitoring and treatment guidance of various cancers including NSCLC. Herein, we report a case of a 21-year-old advanced lung adenocarcinoma patient with a low abundance (0.03%) of EML4-ALK rearrangement identified in plasma ctDNA upon progression on two lines of chemotherapy that demonstrated long-term complete response to alectinib (>13 months) including metastatic brain tumors. Patient's clinical and pathologic characteristics, computerized tomography (CT) scans and brain magnetic resonance imaging (MRI) were reviewed retrospectively. Taken together, our report not only reinforces the translational utility of NGS-based genomic sequencing of liquid biopsy in guiding clinical practice, but also highlights the superior efficacy of alectinib than chemotherapy in ALK+ NSCLC with brain metastases, albeit at a low variant allele abundance.

Prognostic analysis of patients with mutant and wild-type EGFR gene lung adenocarcinoma

Purpose

The purpose of this study was to investigate the relationship between epidermal growth factor receptor (EGFR) gene mutation and clinicopathological features of lung adenocarcinoma, and the prognostic and therapeutic value of EGFR.

Methods

EGFR gene mutations were detected in 424 patients with lung adenocarcinoma by amplification refractory mutation system (ARMS).

Results

The total EGFR gene mutation rate was 55.2% (234/424) and EGFR gene mutation rates were statistically different in gender, smoking status, and pathological degree (P<0.05). The overall survival (OS) time of lung adenocarcinoma patients with mutation of exon 18 was lower than those with mutation of exon 19 and exon 21 (both P<0.05), but no significant difference was seen between those with mutation of exon 19 and exon 21 (P>0.05). Among 424 cases of lung adenocarcinoma, multivariate analysis showed that EGFR gene mutation, age, gender, clinical stages, and pathological degree (P<0.05) were statistically significant prognostic factors. In multivariate analysis, prognostic factors of patients with EGFR gene mutation were associated with EGFR-TKI treatment, surgery treatment, pathological degree, clinical stages, and age (P<0.05), whereas in patients without EGFR gene mutation, prognostic factors were related to surgery treatment, pathological degree, clinical stages, gender, age, and smoking status (P<0.05).

Conclusion

The OS time of patients with mutation of exon 18 was lower than those of exon 19 and exon 21. EGFR-TKI treatment was an independent positive predictor in patients with EGFR gene mutation. Surgery treatment, age, clinical stages, and pathological degree were independent prognostic factors in Chinese patients with lung adenocarcinoma no matter whether with EGFR gene mutation or not.

Different subtypes of EGFR exon19 mutation can affect prognosis of patients with non-small cell lung adenocarcinoma

Aims

In this study, we determined whether different subtypes of epidermal growth factor receptor (EGFR) exon19 mutation are associated with the therapeutic effect of EGFR-tyrosine kinase inhibitors (TKIs) on advanced non-small cell lung adenocarcinoma.

Methods

A total of 122 patients with stage III or IV non-small cell lung adenocarcinoma were retrospectively reviewed. Clinical characteristics of these patients, including progression-free survival (PFS) outcome for EGFR-TKI treatment, were analyzed.

Results

According to the mutation pattern, we classified the in-frame deletions detected on EGFR Exon19 into three different types: codon deletion (CD), with a deletion of one or more original codons; codon substitution and skipping (CSS), with a deletion of one or two nucleotides but the residues could be translated into a new amino acid without changing following amino acid sequence; CD or CSS plus single nucleotide variant (SNV) (CD/CSS+SNV), exclude CD or CSS, there’s another SNV nearby the deletion region. The clinical characteristics of three groups were analyzed and as a result, no significant difference was found. By comparing the average number of missing bases and amino acids of the three mutation subtypes, it could be discovered that the number of missing bases and amino acids of the three mutation subtypes is diverse, and group CSS> group CD> group CD/CSS+SNV. Finally, survival analysis was performed between three groups of patients. The median PFS of group CD, group CSS and group CD/CSS+SNV was 11 months, 9 months and 14 months respectively. There was a distinct difference in the PFS between group CSS and group CD/CSS+SNV (P = 0.035<0.05), and the PFS of group CD/CSS+SNV was longer.

Conclusions

Different mutation subtypes of EGFR exon19 can predict the therapeutic effect of EGFR-TKIs on advanced non-small cell lung adenocarcinoma.