Abstract 506: Dissecting the genomic and tumor immune microenvironment factors associated with disease recurrence in resected stage I NSCLC

Abstract Background: Patients with early-stage non-small cell lung cancer (NSCLC) are at substantial risk for disease recurrence after surgical resection, and the discovery of biomarkers that predict disease recurrence has been challenging. We sought to identify genomic and immunologic factors associated with recurrence after surgery in stage I NSCLC. Methods: We collected clinicopathologic data from patients with resected stage I NSCLC (AJCC 8th Edition) which underwent multiplexed immunofluorescence for CD8+, FOXP3+, PD-1+, and PD-L1. A subset of these samples also had next-generation sequencing performed to identify genomic alterations and tumor mutational burden (TMB). A bidirectional stepwise elimination was applied on variables with a univariable disease-free survival (DFS) p-value <0.25. The final multivariable Cox model was validated with internal bootstrapping (B=300). Results: A total of 252 cases were included. After a median follow-up of 25.6 months from the time of surgery, 47 cases (18.7%) experienced recurrence, with a 2-year DFS rate of 82.9%, and a 2-year overall survival (OS) rate of 97.9%. Shorter DFS was associated with higher TMB, increased PD-L1 expression, and greater numbers of intratumoral (IT) CD8+, PD-1+, and PD-1+CD8+ immune cells, as well as increased CD8+ and FOXP3+ T cells at the tumor stroma interface (TSI) in univariable analyses (p<0.05). Multivariable analysis showed that shorter DFS was associated with increasing TMB and higher PD-L1 tumor cell expression. We observed a difference by immune cell localization and risk of recurrence: shorter DFS was associated with higher IT but lower TSI PD-1+ immune cells, and higher IT but lower TSI FOXP3+ T cells (Table). Internal bootstrap validation showed good model performance (C-index = 0.74). Conclusion: Genomic analysis and immunophenotyping of stage I NSCLCs can identify cases at greatest risk of disease recurrence after surgical resection. Table. Univariable and multivariable analysis Disease-free survival Univariable HR [95%CI] p-value Multivariable HR [95%CI] p-value Stage at diagnosis - 0.10 – – IA1 1.52 [0.58, 3.97] IA2 2.61 [0.95, 7.20] IA3 2.61 [1.03, 6.63] IB Histology - 0.42 Adenocarcinoma 1.38 [0.65, 2.97] Squamous Age* 1.02 [0.99, 1.06] 0.19 – – TMB* 1.09 [1.05, 1.12] <0.001 1.09 [1.05, 1.13] <0.001 Smoking* (pack-years) 1.01 [1.00, 1.02] 0.008 – – Smoking history - 0.012 – – Never 5.24 [1.27, 21.7] Former Current 4.92 [0.82, 29.5] Surgical treatment - 0.084 - 0.074 Lobectomy 1.80 [0.89, 3.62] 2.18 [0.93, 5.14] Sublobar Intratumoral** 1.09 [1.03, 1.16] 0.015 - – CD8+ 1.22 [1.10, 1.36] 0.002 1.80 [1.13, 2.87] 0.014 PD-1+ 1.51 [1.20, 1.90] 0.004 - – 0.004 PD-1+ CD8+ 1.22 [1.04, 1.44] 0.053 0.15 [0.04, 0.55] FOXP3+ Tumor-Stroma Interface** 1.06 [1.01, 1.11] 0.033 - - CD8+ 1.10 [1.01,1.20] 0.056 0.71 [0.56, 0.91] 0.007 PD-1+ 1.21 [0.99, 1.48] 0.100 - - PD-1+ CD8+ 1.28 [1.03, 1.59] 0.037 2.42 [1.49, 3.95] <0.001 FOXP3+ PD-L1 expression* 1.02 [1.01, 1.03] <0.001 1.03 [1.01, 1.04] <0.001 Tumor Proportion Score (TPS) 1.02 [1.01, 1.04] - - Immune cells 0.011 *Per unit increase. ** Per 100 units increase. Intratumoral, is defined as the region of the slide consisting of tumor beyond the tumor-stroma interface. Tumor-Stroma Interface is defined as the region within 40 microns to either side of the defined border between tumor and stroma. Citation Format: Joao Victor Alessi, Zihan Wei, Biagio Ricciuti, James Lindsay, Victor R. Vaz, Adriana Barrichello, Bijaya Sharma, Kristen D. Felt, Fangxin Hong, Lynette M. Sholl, Scott J. Rodig, Mark M. Awad. Dissecting the genomic and tumor immune microenvironment factors associated with disease recurrence in resected stage I NSCLC [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 506.