L’INTÉRÊT DE LA BIOPSIE LIQUIDE DANS LA DÉTECTION DES MUTATIONS EGFR DANS LE CBNPC

Abstract

Non-small cell lung cancer (NSCLC) is currently a major public health problem both globally and nationally. It remains one of the most common and deadly cancers, primarily because it is often diagnosed at an advanced stage. In this context, the identification of molecular alterations has become essential for guiding therapeutic management toward personalized medicine.Among the biomarkers currently in use; mutations in the EGFR gene play a central role. Screening for these mutations helps identify patients likely to benefit from targeted therapy with tyrosine kinase inhibitors (TKIs). However, tissue analysis, which remains the gold standard, has several limitations. In this context, liquid biopsy has emerged as an innovative, minimally invasive approach that allows for the analysis of circulating tumor DNA.

The objective of this study was to evaluate the utility of liquid biopsy in detecting EGFR gene mutations in patients with advanced NSCLC.

A cross-sectional observational study with a prospective component was conducted at the Cancer Control Center (CLCC) in Sétif. Twenty-nine patients with NSCLC were included.. Analysis of EGFR mutations (exons 18 through 21) was performed using circulating tumor DNA extracted from plasma. After DNA extraction, mutations were detected using polymerase chain reaction (PCR), which allowed for the identification of the main molecular alterations in the EGFR gene.

The results showed a predominance of male patients, as well as a majority of adenocarcinoma cases and metastatic stages. EGFR-activating mutations were detected in 13.64% of patients analyzed via liquid biopsy, with a predominance of exon 19 deletions. The T790M resistance mutation was also found in some patients. A comparative analysis between liquid biopsy and tissue biopsy revealed 100% concordance, with sensitivity, specificity, positive predictive value, and negative predictive value all at 100%.

This study demonstrated that liquid biopsy is a relevant complementary diagnostic tool for detecting EGFR mutations in patients with NSCLC. Its minimally invasive nature, rapid turnaround time, and high specificity make it a particularly attractive alternative when a tissue biopsy is difficult to perform or yields insufficient material. Nevertheless, due to its moderate sensitivity and the risk of false-negative results, tissue biopsy remains the gold standard when available.

Keywords: Non-small cell lung cancer, NSCLC, EGFR, liquid biopsy, circulating tumor DNA, tissue biopsy, targeted therapies.