1315 - Cytology Samples (S) for EGFR and KRAS Mutation (MUT) Testing in Non-Small-Cell Lung Cancer (NSCLC). Experience from a Single Institution

Abstract

ABSTRACT Background Targeted therapy has yielded impressive clinical outcomes in advanced NSCLC. For molecular testing, cytology samples are not commonly used since the tumor content is less likely to be adequate. At ICO-Badalona, Hospital Germans Trias i Pujol we have used cytology specimens when biopsies are not available. We describe the general results when using cytology specimens in NSCLC to detect EGFR and KRAS mut. Methods From January 2007 to February 2012, 227 cytology samples from patients with NSCLC were collected at the Department of Pathology as cell blocks or fresh specimens extended over an appropriate slide (MembraneSlide 1.0 PEN, Zeiss®). Tumor cells (8-150) were captured by laser microdissection. DNA sequencing for EGFR mut at exons 18, 19, 21, and KRAS mut at codons 12 and 13 and allelic discrimination technique for EGFR mut at exon 20 were performed at Molecular Biology Laboratory (ICO-Badalona). Results EGFR mut were tested in 227 s. The overall output was 86.3% (15 not evaluable, 8 insufficient tissue, 4 no tumor cells, 4 not done). EGFR mut were detected in 8.81% (20/227). KRAS mut were tested in 41 s with results in 33, 80.5% (2 not evaluable, 3 insufficient tumor cells 1 no tumor and 2 not done). KRAS mut were positive in 14.6% (6/41). The output for cell block was 83.3% (124/148) and testing was not possible in 24 s (11 not evaluable, 6 insufficient tumor cells, 4 not tumor and 3 not done). The output for fresh specimens was 91.1% (72/79) and was not possible in 7 s (4 not evaluable, 2 insufficient tumor cells and 1 not done). Conclusions Our results support the use of cytology samples for EGFR and KRAS molecular testing in NSCLC when biopsy specimens are not available. Both fresh specimens and cytology blocks have been used and are suitable for molecular testing. Disclosure All authors have declared no conflicts of interest.