[Detection of lung cancer driver genes by next-generation sequencing: a comparative analysis of plasma and histological/cytological samples]

Abstract

Objective: To compare the results of plasma samples and histological/cytological samples for detection of lung cancer driver gene by next-generation sequencing (NGS), to provide reference for sampling selection of clinical patients. Methods: A retrospective analysis was performed on 220 patients with lung cancer who were admitted to Quanzhou First Hospital in Fujian Province from May 2017 to May 2024, and NGS detection of lung cancer driver gene was performed on both plasma samples and histological/cytological samples. Histological specimens included biopsy or surgical resection of lung cancer, cervical lymph nodes and pleural metastases; the cytological specimen was pleural fluid cell wax block. Specimens were divided into plasma group (experimental group) and matched histological and cytological group (control group). Eight gene variants recommended by the guidelines were EGFR mutation, ALK rearrangement, ROS1 rearrangement, BRAF V600 mutation, RET rearrangement, MET exon 14 jump mutation, KRAS mutation, and NTRK1/2/3 rearrangement. The detection results of the two groups of specimens were compared and analyzed. Results: Among the 220 cases, 183 were adenocarcinoma, 23 were squamous cell carcinoma and 14 were non-small cell lung cancer. There were 4 cases in stage Ⅰ, 3 cases in stage Ⅱ, 24 cases in stage Ⅲ, and 189 cases in stage Ⅳ. In the plasma group, 120 cases were positive, the detection rate was 54.5%; There were 152 positive cases in the control group, the detection rate was 69.1%; the detection rate in the plasma group was lower than that in the control group (χ²=6.12, P<0.05). The detection rate of plasma in patients with stage Ⅰ/Ⅱ/Ⅲ was 12.9% (4/31), which was significantly lower than that in stage Ⅳ (61.4%; χ²=22.10, P<0.05). In the early clinical stage (stage Ⅰ/Ⅱ) of 7 cases, 3 cases were positive in the control group, while all were negative in the plasma group. There were 24 stage Ⅲ cases, 8 were positive in the control group and 4 were positive in the plasma group. Among the positive cases in the control group, 34 were negative and 4 were not detected in the matched plasma group. In the plasma positive cases, there were 2 negative cases and 4 partial mutations were not detected in the matched control group. Among these 6 cases, 5 were treated patients, and the mean mutation abundance of corresponding plasma positive genes was 1.5%. There were 110 cases with the same positive result (the same mutation site) and 66 cases with the same negative result, with agreement rate of 80.0% (176/220). The sensitivity and specificity of the plasma group were 75.0% (114/152) and 91.7% (110/120), respectively. Conclusions: When NGS is used for lung cancer driver gene detection, the positive rate of plasma samples is lower than that of tissue/cytology samples, but the consistency rate with the latter can reach 80%, and the sensitivity is higher than 70%, which has a good clinical detection efficiency, especially for patients with non-small cell lung cancer stage Ⅳ.