Abstract 215P
Background
Lymph nodes (LNs) are crucial for effective perioperative immunotherapy but resected completely after surgery. The limited efficacy of adjuvant immunotherapy is also suspected to be related to systemic lymphadenectomy. The associated theories have been thoroughly investigated in breast cancer, but still remain absent in non-small cell lung cancer (NSCLC).
Methods
cT1-4N0-1M0 NSCLC patients treated with neoadjuvant immunochemotherapy (nICT), and received radical surgery were retrospectively collected. The primary outcome was the clearance rate of mediastianl LNs (ypN0/N1). LOWESS regression were conducted to explore the relationship among LNs dissection count, EFS, and OS. Single-cell transcriptome and TCR sequencing were conducted in the tumor-draining LNs treated by Adebrelimab (anti-PD-L1 inhibitors).
Results
From 2019 to 2021, 132 neoadjuvant-treated cN0/N1 NSCLC patients were collected. Of those, 39.4% were stage IIIA, 75.8% were squamous cell carcinoma, and 62.9% received adjuvant treatment. The pCR and MPR rates were 46.9% and 62.1%. With a median follow-up of 46.5 months, the 3-year EFS and OS were 89.9% and 96.1%. For the primary outcome, the ypN0/N1 rate was 98.5% (130/132). Resected LNs counts (LN counts ≤16 vs. >16) were not associated with EFS or OS benefits, but those patients with extensive LNs resection (LN counts >16) seemed to experience higher risk of recurrence in the whole and non-MPR cohort. The single-cell RNA profiling showed that central memory T cells, effector memory T cells, and memory B cells were selectively retained in tumor-draining LNs. Cell-cell communication was specifically observed between migratory dendritic cells and memory T cells. TCR trajectory revealed the clonal differentiation between (precursor) exhausted tumor-specific T cells and memory T cells.
Conclusions
Omission of mediastinal LNs is safe in cN0/N1 NSCLC patients with nICT due to the promising ypN0/N1 rate. Single-cell analysis further indicated the necessity of LNs preservation with regard to the abundant of tumor-specific memory T cells. Negative LNs should be preserved in order to improve the efficacy of adjuvant immunotherapy.
Clinical trial identification
NCT06292052; Release data: 2024-02-23.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.