Abstract 1153P
Background
The incidence of multifocal lung adenocarcinomas (MLAs) increased remarkably over the past decade, owing to the advancement in imaging technology. The classification of MLAs subtypes, including multiple primary lung adenocarcinomas (MPLAs) and intrapulmonary metastases (IPMs), has great clinical significance in staging and treatment decisions. However, the application of molecular approaches in MLAs diagnosis, especially in pN0M0 patients, has not been well-investigated.
Methods
We retrospectively included 45 pN0M0 MLAs patients (101 lesion pairs) as the study group and 5 patients with intrathoracic metastases as positive controls. The comprehensive histologic assessment (CHA) and broad panel next-generation sequencing (NGS) approaches were performed and compared. The non-synonymous alterations (NSAs) and Jaccard coefficient were analyzed for each lesion pair.
Results
Based on CHA, 12 (11.9%) and 89 (88.1%) lesion pairs in the study group were classified as IPMs and MPLAs, respectively. Therefore, 10 (22.2%) patients were diagnosed as IPMs and 35 (77.8%) were classified as MPLAs by CHA. Using NGS analysis, we found a high concordance of NSAs between primary and metastatic lesions in 5 patients with intrathoracic metastases. We, thereby, used NSAs and Jaccard coefficient to classify MLAs subtypes in the study group. 16 (16%) lesion pairs were diagnosed as IPMs (mean Jaccard=0.68; mean shared NSA=3.44) whereas 84 (84%) lesion pairs were MPLAs (mean Jaccard=0.08; mean shared NSA=0.37), resulting in 31 (70.5%) and 13 (29.5%) patients being classified as MPLAs and IPMs, respectively. The discordant rate between the CHA and NGS was 29.5% at patient-level and 18% at lesion-level, with higher discordance in IPMs. Among the 13 patients with discordant results, 2 patients who were diagnosed as MPLAs by CHA were likely to be IPM based on further imaging and prognosis analyses, suggesting the potential higher accuracy of the NGS approach.
Conclusions
We characterized MLAs classification in pN0M0 patients using both CHA and NGS. Our results demonstrated significant discordance between the diagnostic results from the two methods, suggesting the importance to classify MLAs using unbiased molecular approaches.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Scientific Research of Department of Science & Technology of Liaoning Province.
Disclosure
P. Yang: Financial Interests, Personal and Institutional, Full or part-time Employment: Nanjing Geneseeq Technology Inc. Y. Xu: Financial Interests, Personal and Institutional, Full or part-time Employment: Nanjing Geneseeq Technology Inc. X. Ren: Financial Interests, Personal and Institutional, Full or part-time Employment: Nanjing Geneseeq Technology Inc. X. Wu: Financial Interests, Personal and Institutional, Full or part-time Employment: Nanjing Geneseeq Technology Inc. All other authors have declared no conflicts of interest.