Low correspondence of EGFR mutations in tumor tissue and paired serum of non-small-cell lung cancer patients

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.

Blood as a Substitute for Tumor Tissue in Detecting EGFR Mutations for Guiding EGFR TKIs Treatment of Nonsmall Cell Lung Cancer: A Systematic Review and Meta-Analysis

Tumor tissues are often absent or insufficient for testing epidermal growth factor receptor (EGFR) mutations to guide EGFR tyrosine kinase inhibitors (TKIs) treatment of patients with nonsmall cell lung cancer (NSCLC). 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. MEDLINE, EMBASE, and the Cochrane Library were searched for studies that provided data to estimate the accuracy of blood testing against tissue testing in NSCLC patients and/or those directly compared the efficacy of EGFR TKIs in EGFR mutant and wild-type patients according to sources of specimens. Sensitivity, specificity, and concordance rate were used as measures of the accuracy. Risk ratio (RR) for objective response and hazard ratio (HR) for progression-free survival (PFS) and overall survival (OS) were used as measures for treatment efficacy. We combined the effects by using the fixed-effects model unless there was evidence of heterogeneity, in which case a random-effects mode was used. This systematic review included 25 studies with 2605 patients. The pooled overall sensitivity, specificity, and concordance rate were 0.61, 0.90, and 0.79, respectively. Serum showed lower sensitivity (0.56 vs 0.65) but higher specificity (0.95 vs 0.85) and higher concordance (0.86 vs 0.74) than plasma. EGFR mutations (exon 19 or 21) in blood were significantly associated with objective response (RR: 4.08; 95% confidence interval [CI] 2.48-6.70), PFS (HR: 0.72; 95% CI 0.64-0.80), and OS (HR: 0.71; 95% CI 0.50-0.99). Importantly, the association of the mutations with the 3 clinical outcomes for serum was similar to that for tumor tissue and higher than that for plasma. Blood, in particular serum, is a good substitute when tumor tissue is absent or insufficient for testing EGFR mutations to guide EGFR TKIs treatment in patients with NSCLC. EGFR mutation positivity in blood could be used to recommend EGFR TKIs treatment, but the absence of blood positivity should not necessarily be construed with confirmed negativity.

Limitations in the Use of Serum Epidermal Growth Factor Receptor Mutations as Prognostic Markers for Non-Small-Cell Lung Cancer

OBJECTIVES

In this study, we surveyed patients with advanced non-small-cell lung cancer (NSCLC) who were undergoing tyrosine kinase inhibitor (TKI)-targeted therapy. Our aim was to determine whether epidermal growth factor receptor (EGFR) mutations in serum circulating tumor (ct)DNA are useful prognostic markers for NSCLC. Sujects and Methods: Serum samples were collected from 300 patients with NSCLC that included adenocarcinoma (ADC, n = 155) and squamous cell carcinoma (SCC, n = 145). DNA was extracted from the sera for the nested polymerase chain reaction (PCR) amplification of EGFR exons 18, 19 and 21 mutations. Direct sequencing of the PCR products was carried out in an automated 3730 sequencer.

RESULTS

The EGFR exons 18, 19 and 21 were successfully detected in the serum samples of 300 NSCLC patients. No EGFR mutation was found in the blood samples regardless of the characteristics of gender, age, ADC and SCC status or smoking history.

CONCLUSION

No mutations in EGFR exons 18, 19 or 21 were identified in the serum ctDNA of these advanced-stage NSCLC patients undergoing TKI-targeted therapy. More studies are needed on the use of EGFR mutations in serum ctDNA as guidance for TKI-targeted therapy.

Comparison of epidermal growth factor receptor mutation statuses in tissue and plasma in stage I-IV non-small cell lung cancer patients

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations play essential roles in the treatment of non-small cell lung cancer (NSCLC) patients using EGFR tyrosine kinase inhibitors. Detection of EGFR mutations in blood cell-free DNA (cfDNA) seems promising. However, the mutation status in the plasma/serum is not always consistent with that in the tissues.

OBJECTIVES

The aims of this study were to compare the mutation statuses in plasma to those in tissues and thus to determine the specific subgroups of NSCLC patients who may be the best candidates for EGFR mutation analyses using blood cfDNA.

METHODS

A total of 111 pairs of tissue and plasma samples were collected. Mutant-enriched PCR and sequencing analyses were performed to detect EGFR exon 19 deletions and exon 21 L858R mutations.

RESULTS

Mutations were discovered in 43.2% (48/111) of the patients. The overall rate of consistency of the EGFR mutation statuses for the 111 paired plasma and tissue samples was 71.2% (79/111). The sensitivity and specificity rates of detecting EGFR mutations in the plasma were 35.6% (16/45) and 95.5% (63/66), respectively. The disease stage and tumor differentiation subgroups showed significantly different detection sensitivities; the sensitivity was 10% in early-stage patients and 56% in advanced-stage patients (p = 0.0014). For patients with poorly differentiated tumors, the sensitivity was 77.8%, which was significantly different from those with highly differentiated (20%; p = 0.0230) and moderately differentiated tumors (19%; p = 0.0042).

CONCLUSION

Blood analyses for EGFR mutations may be effectively used in advanced-stage patients or patients with poorly differentiated tumors.