Clinicopathologic characteristics and outcome of patients with different EGFR mutations

Heterogeneous distribution of EGFR mutation in NSCLC: Case report

Background

We herein report the case of a patient with advanced lung adenocarcinoma who presented a heterogeneous distribution of EGFR mutation.

Case report

A 74-year-old Moroccan male former smoker was diagnosed with advanced lung adenocarcinoma, harboring S768I exon 20 substitution mutation confirmed by Real Time PCR and Pyrosequencing, but not detected by direct sequencing despite 70% of tumor cells. The present report describes a case of minor histologic intratumoral heterogeneity with heterogeneous distribution of EGFR mutation.

Conclusion

Both sensitivity and specificity of molecular methods can provide evidence of intratumoral heterogeneity, which may explain the mismatch between the validation of oncology biomarkers and predicting therapeutic response to targeted therapy.

Correlation of Epidermal Growth Factor Receptor Mutation With Major Histologic Subtype of Lung Adenocarcinoma According to IASLC/ATS/ERS Classification

OBJECTIVE

Our prospective study aims to define the correlation of EGFR(epidermal growth factor receptor) mutations with major histological subtypes of lung adenocarcinoma from resected and non-resected specimens, according to the WHO 2015 classification, in Moroccan North East Population.

METHODS

Epidermal growth factor receptor mutations of 150 primary lung adenocarcinoma were performed using Real-Time PCR or SANGER sequencing. SPSS 21 was used to assess the relationship between histological subtypes of lung adenocarcinoma and EGFR mutation status.

RESULTS

25 mutations were detected in the series of 150 lung adenocarcinomas, most of which were found in cases with papillary, acinar, patterns than without these patterns and more frequently occurred in the cases without solid pattern than with this pattern. A significant correlation was observed between EGFR mutation and acinar (P = 0,024), papillary pattern (P = 0,003) and, negative association with a solid pattern (P < 0,001). In females, EGFR mutations were significantly correlated with the acinar pattern (P = 0,02), whereas in males with the papillary pattern (P = 0,01). Association between the histologic component and exon 19 deletions and exon 21 mutations were also evaluated and, we found a significant correlation between the papillary major pattern with exon 19 mutations (P = 0,004) and, ex21 with the acinar component (P = 0,03).

CONCLUSION

An analysis of resected and non-resected lung ADC specimens in 150 Moroccan Northeast patients, revealed that acinar and papillary patterns may predict the presence of a mutation in the EGFR gene. While the solid major pattern may indicate a low mutation rate of the EGFR gene.

Uncommon EGFR mutations in non-small-cell lung cancer: A systematic literature review of prevalence and clinical outcomes

Mutations in exons 18-21 of the epidermal growth factor receptor gene (EGFR) can confer sensitivity to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small-cell lung cancer (NSCLC). Deletions in exon 19 or the exon 21 L858R substitution comprise approximately 85% of mutations, but comparatively few data are available on the remaining "uncommon" mutations. We conducted a systematic literature review to identify evidence on uncommon EGFR mutations in locally advanced/metastatic NSCLC (PROSPERO registration number: CRD42019126583). Electronic screening and congress searches identified studies published in 2012-2020 including patients with locally advanced/metastatic NSCLC and uncommon EGFR mutations (excluding T790M). We assessed the prevalence of uncommon mutations (in studies using direct sequencing of exons 18-21), and compared response to treatment and progression-free survival (PFS) in patients with common versus uncommon mutations and in those with exon 20 mutations versus other uncommon mutations. We identified 64 relevant studies. Uncommon mutations constituted 1.0-18.2% of all EGFR mutations, across 10 studies. The most frequently reported uncommon mutations were G719X (0.9-4.8% of all EGFR mutations), exon 20 insertions (Ex20ins; 0.8-4.2%), L861X (0.5-3.5%), and S768I (0.5-2.5%). Patients with common mutations typically experienced better treatment response and longer PFS on EGFR-TKIs than patients with uncommon mutations; Ex20ins mutations were associated with less favourable outcomes than other uncommon mutations. This review shows that uncommon mutations may comprise a clinically significant proportion of the EGFR mutations occurring in NSCLC, and highlights disparities in EGFR-TKI sensitivity between different uncommon mutations.

How specific molecular-targeted agents can make obsolete a 'one size fits all' approach in EGFR-mutated NSCLC treatment (Review)

Despite many advances in the latest period, lung cancer remains the cancer with the highest mortality. The latest developments concerning lung cancer treatment have changed the clinical practice by prolonging patient survival; however, unfortunately, there remains a high mortality rate firstly due to disease aggressivity and secondly through lack of early diagnosis and screening programs. Currently, researchers and clinicians are talking about personalized cancer treatment, and a complete diagnostic evaluation should consider, in addition to staging and histology, molecular aberrations, and genetics of the tumor tissue. The development of tyrosine kinase inhibitors (TKIs) has led to an improvement in survival for patients with EGFR mutations, this being the most studied driver mutation in adenocarcinoma; and at the same time an important predictive factor for patient outcome following the treatment with TKIs. Reseach must investigate the different TKI combination strategies in order to overcome resistance and to increase patient survival. Currently, there are ongoing clinical trials that will probably change the therapeutic approach for EGFR-mutated advanced or metastatic NSCLC patients.

Efficacy and Safety of First-Generation EGFR-TKIs Combined with Chemotherapy for Treatment-Naïve Advanced Non-Small-Cell Lung Cancer Patients Harboring Sensitive EGFR Mutations: A Single-Center, Open-Label, Single-Arm, Phase II Clinical Trial

Purpose

This single-center, open-label, single-arm, phase II clinical trial aimed to examine the efficacy and safety of the first-generation EGFR-TKIs combined with chemotherapy among treatment-naïve advanced non-small-cell lung cancer (NSCLC) patients harboring sensitive EGFR mutations.

Materials and Methods

Patients with advanced EGFR-mutant NSCLC were given concurrent gefitinib (250 mg orally daily) and 3-week cycle of carboplatin plus pemetrexed for 4 to 6 cycles, followed by gefitinib maintenance until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were overall survival (OS), objective response rate (ORR), disease control rate (DCR) and safety. This trial was registered at ClinicalTrials.gov (NCT02886195).

Results

Of the 21 patients enrolled in this study, a 76.2% ORR and 100% DCR were observed and a higher ORR was seen in patients with EGFR 21L858R mutations than in those with 19del mutations (P = 0.012). The subjects had a median PFS of 15.0 months and a median OS of 26.0 months, and numerically longer PFS was seen in patients with EGFR 21L858R mutations than in those with 19del mutations (P = 0.281). There were 15 NSCLC patients without cerebral metastases at baseline, with 4 cases developing cerebral metastases during the treatment, and the 6-, 12- and 24-month cumulative incidence rates of the central nervous system metastasis were 6.67%, 13.3% and 26.7%, respectively. There were 17 subjects with progressive diseases tested for EGFR T790M mutations, and 11 cases were positive for T790M mutations. Grade 3 toxicity included neutropenia (9.5%), leukopenia (4.8%), liver dysfunction (9.5%) and diarrhea (4.8%), and no grade 4 adverse events or treatment-related death occurred.

Conclusion

The combination of first-generation EGFR-TKIs and chemotherapy achieves a satisfactory PFS, ORR and DCR and well-tolerated toxicity in advanced NSCLC patients with EGFR mutations, notably in patients with EGFR L858R mutations.

Prognostic value of quantitative measurement of EGFR mutation using peptide nucleic acid clamping in advanced EGFR mutant non-small cell lung cancer patients

Background

The presence of EGFR mutation in patients with advanced non‐small cell lung cancer (NSCLC) plays an important role in determining the appropriate treatment, response, and survival. Therefore, this study attempted to predict the prognosis of NSCLC patients using data from quantitative mutation measurements.

Methods

The data of patients with advanced NSCLC who underwent EGFR mutation testing using the peptide nucleic acid (PNA) mediated clamping method at the Pusan National University Hospital from October 2015 to December 2017 were retrospectively analyzed. The efficiency of PNA clamping was determined by measuring the threshold cycle (C_t) value. The ΔC_t−1 value (standard C_t value minus sample C_t value) was calculated to quantify EGFR mutation.

Results

During the study period, 71 patients were treated with EGFR‐tyrosine kinase inhibitors. The cutoff point for the ΔC_t−1 value derived from the receiver operating characteristic curve was 5.32. A survival benefit was observed in the group with an ΔC_t−1 value > 5.32 or with a common EGFR mutation type compared to the group with an ΔC_t−1 value < 5.32.

Conclusion

EGFR mutation testing using PNA clamping may predict patient survival, especially in patients with common EGFR mutations, such as exon 19 deletion or L858R. A higher ΔC_t−1 value correlates with better survival.