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MA21 - Non EGFR/MET Targeted Therapies (ID 153)
- Event: WCLC 2019
- Type: Mini Oral Session
- Track: Targeted Therapy
- Presentations: 1
- Now Available
MA21.02 - Genomic Origin and EGFR-TKI Efficacy of Pulmonary Adenosquamous Carcinoma (Now Available) (ID 578)
14:30 - 16:00 | Author(s): Dan Hu
Lung adenosquamous carcinoma (ASC) is a heterogeneous disease that comprises of both adenocarcinoma (AC) and squamous cell carcinoma (SCC) components. Their genomic profile, evolutionary origin, and clinical management remain controversial. Objective of this study is to define the genomic origin of this heterogeneous tumor by independent genomic analyses of the AC and SCC components.Method
Surgical ASCs were collected. AC component and SCC component were obtained separately by microdissection, and Lymph node (LN) metastases were gathered. Targeted sequence was performed for the two components using a 1021-gene panel, independently. Evolutionary relationship of the two components was analyzed. The independent cohorts of adenocarcinoma (n=170) and squamous cell carcinomas (n=62) were used for comparison. EGFR and concomitant mutations with response to EGFR-TKI were analyzed. Retrospective 517 ASCs underwent EGFR detections were collected from 11 centers. Objective response rate (ORR), disease control rate (DCR) and progression free survival (PFS) were analyzed in EGFR-positive patients received EGFR-TKIs.Result
28 ASCs were collected. NGS was performed on AC component and SCC component samples, respectively. The most frequent alterations in 28 ASCs were EGFR mutation (79%), TP53 mutation (68%), MAP3K1 mutation (14%), EGFR amplification (32%), and MDM2 amplification (18%). 27 patients had trunk variations in the both components suggesting the monoclonal origin of ASCs. The prevalence of trunk mutations was correlated to those of AC, indicating that ASC might originate from AC. Only one patient did not carry any trunk variations between AC and SCC components, which were clearly and geographically distinguishable under the microscope. 22 had AC component or/and SCC component specific variations suggesting the common event of branch evolution. The 23 LNs of 13 patients mainly contained AC and ASC components (AC, SCC, and ASC: 11, 1, and 11, respectively), and each of the LNs carried the trunk mutations of the primary ASC. Like pure AC, the alterations of L858R and Exon 19 Dels of EGFR were common in the 28 ASCs. Unfortunately, these patients have not been treated with TKIs. Further, of 517 retrospective ASCs from 11 centers, 51.8% were EGFR-positive. For the 129 EGFR-positive ASCs who had received TKIs, the ORR and DCR were 56.6% and 89.1%, respectively. The median PFS was 10.1 months (95% CI: 9.0-11.2).
The AC and SCC components share a monoclonal origin, and a majority have branching evolution. ASC may represent a subtype of adenocarcinoma with EGFR mutation being the most common genomic anomaly and sharing similar efficacy to EGFR-TKIs.
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