Methodological and TNM Focus-Based Comparison of EGFR Mutation Status in Non-Small-Cell Lung Carcinomas

Area of Science:

• Oncology
• Molecular Diagnostics
• Pathology

Background:

• Epidermal growth factor receptor (EGFR) mutations are key drivers in non-small-cell lung cancer (NSCLC).
• Tyrosine kinase inhibitor (TKI) therapy offers significant clinical benefits for NSCLC patients with EGFR mutations.
• Efficient and cost-effective EGFR mutation analysis is crucial for guiding treatment decisions.

Purpose of the Study:

• To compare the effectiveness of cytological versus histological samples for EGFR mutation detection in NSCLC.
• To evaluate differences in EGFR mutation incidence across primary, nodal, and metastatic sites.

Main Methods:

• Retrospective review of 420 NSCLC cases (cytological, small biopsies, surgical samples) from 2016-2022.
• Analysis of EGFR mutation detection rates in cytological and histological specimens.
• Comparison of mutation frequencies in primary tumors, mediastinal lymph nodes, and distant metastases.

Main Results:

• EGFR mutations were detected in 29.31% of cytology samples versus 9.94% of biopsy samples (P=0.01).
• A significant difference in mutation detection was also observed in pleural samples (P=0.005).
• Mutation rates varied across different anatomical sites: primary foci (11.87%), lymph nodes (19.44%), and distant metastases (12.50%).

Conclusions:

• Cytological specimens, particularly cell blocks from liquid-based samples, show higher efficacy for EGFR mutation detection compared to traditional histological methods.
• These findings underscore the value of cytological samples in facilitating molecular-based treatments for NSCLC.
• Utilizing cytological specimens can optimize diagnostic yield and support personalized therapy selection in NSCLC management.