ESMO Congress 2024 | OncologyPRO

Abstract 1383P

Background

Around 60% of NSCLC patients in China have actionable genetic variants, with detection rates influenced by various factors such as diagnostic methods, sample types, and disease stage. Yet, a comparative study on mutation frequency across sample types in Chinese NSCLC patients is lacking.

Methods

We conducted a retrospective analysis of 5,183 NSCLC patients tested for actionable targets at the Beijing Cancer Hospital and Shanghai Pulmonary Hospital between 2018 and 2023. This cohort included 5,051 patients with lung adenocarcinoma (LUAD) and 132 patients with lung squamous cell carcinoma (LUSC). For LUAD, the samples comprised 3,130 surgical resections, 1,633 biopsies, and 288 pleural effusions. In LUSC, 30 surgical resections and 102 biopsies were analyzed. All samples underwent PCR testing (Amoydx, Xiamen) for nine actionable targets (EGFR, ALK, MET EX14, BRAF, HER2, ROS1, HER2, RET, KRAS).

Results

The positivity rates for each actionable target in adenocarcinoma are presented in the table. EGFR mutations were significantly higher in surgical samples compared to biopsy and pleural effusion samples (p<0.05). ALK fusions had a higher positivity rate in pleural effusion samples compared to biopsy and surgical samples (p<0.05). KRAS mutations were significantly more frequent in biopsy samples compared to surgical and pleural effusion samples (p<0.05). The mutation frequencies of the other eight gene variants besides EGFR in pleural effusion, biopsy, and surgical samples were 20.38%, 23.64%, and 21.88% respectively, with no significant differences observed. Additionally, 12% of the squamous cell carcinoma patients harbored actionable targets (Table).

Conclusions

Overall, 79.17%-86.81% of patients with LUAD carry actionable variations, and notably, there are still 10%-12.7% of patients with LUSC who carry actionable variations. EGFR mutations are more common in surgical samples, possibly due to early-stage disease detection. Table: 1383P

	LUAD N=5051			LUSC N=132
	Pleural effusion (%)N=288	Biopsy (%)N=1633	Surgical (%)N=3130	Biopsy (%)N=30	Surgical (%)N=102
EGFR	57.29	56.77	66.42	3.33	4.90
KRAS	4.17	10.10	7.92	0.00	1.96
BRAF	2.08	1.29	1.09	3.33	0.00
ALK	7.64	5.45	3.64	0.00	0.98
ROS1	1.04	1.90	1.31	0.00	2.94
MET	1.04	1.29	1.95	0.00	0.00
HER2	3.13	2.57	2.46	0.00	0.00
NRAS	0.00	0.18	0.06	3.33	0.98
RET	2.78	0.86	1.95	0.00	0.98