Abstract 5781: Molecular positive margin of surgical resections is a strong biomarker for tumor recurrence in pIIIA-N2 NSCLC patients

Abstract

Abstract Background: The high recurrence rate of stage pIIIA-N2 NSCLC patients may reflect inadequate removal of all residual tumor cells despite conventional histologic negative surgery margin. The NGS-detected BRM status was possible to serve as a more accurate examination to identify those patients with a high-risk of postoperative recurrence. Methods: We retrospectively studied 119 stage IIIA-N2 NSCLC patients who received curative-intent surgery plus adjuvant chemotherapy/chemoradiotherapy, and all of the patients were classified with negative resection margin by the conventional histologic method. Each patient had paired tumor and bronchial resection margin (BRM) samples, which were analyzed using next-generation sequencing (NGS) of 474 cancer-related genes, and we explored the prognostic values of various clinical and molecular features. Results: Among the 119 stage IIIA-N2 NSCLC patients with histologic negative resection margins, the BRM samples from 56 patients (47.1%) were positive for tumor mutations, including multiple lung cancer driver mutations. The number and the variant allele frequency of genetic alterations in BRM samples were generally lower than that of the paired tumor samples. Notably, patients who were positive for NGS-detected BRM mutations had significantly shorter disease-free survival (DFS) than the negative patients (p=0.001, HR 2.18, 95%CI 1.37~3.47). Several other clinical/molecular features were also found to be significantly associated with DFS, including the metastatic lymph node ratio (MLNR), smoking history, and KRAS mutation status, and NGS-assessed BRM status remained to be statistically significant in multivariable analysis by including all of these prognostic factors (p =0.020, HR 1.82, 95%CI 1.10~3.02). Conclusions: We demonstrated that the molecular positive margin of surgical resections was a strong and independent biomarker for disease recurrence in pIIIA-N2 NSCLC patients. Our results emphasized the clinical utility of molecular diagnostic approaches to detect minimal residual disease after surgical resection, which could potentially facilitate the stratification of high-risk patients for personalized and appropriate treatments. Citation Format: Li Li, Kewen He, Jiaohui Pang, Yang Xu, Yang Shao, Shuanghu Yuan, Jinming Yu. Molecular positive margin of surgical resections is a strong biomarker for tumor recurrence in pIIIA-N2 NSCLC patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5781.