Multi-scale characterization of tumor-draining lymph nodes in resectable lung cancer treated with neoadjuvant immune checkpoint inhibitors

BACKGROUND: Regional lymph node (LN) acts as a pivotal organ for antitumor immunity. Paradoxically, tumor-draining LNs (TDLNs) are usually the first site of tumor metastasis in lung cancer. It is largely unknown about the association between the status of TDLNs and the response of primary tumor beds to immune checkpoint inhibitors (ICIs) in lung cancer patients. Also, studies characterizing the TDLNs in response to ICIs are scarce. METHODS: We characterized and compared the radiological, metabolic (18F-FDG) and pathologic responses between primary tumor beds and paired TDLNs (invaded/non-invaded) from 68 lung cancer patients who underwent neoadjuvant ICIs plus surgery. Additionally, we performed the spatial profiling of immune and non-immune cells within TDLNs using multiplexed immunofluorescence. Therapy responses (e.g., pathologic complete (pCR) or major response (MPR)) of primary lung tumor beds and paired TDLNs were investigated separately. FINDINGS: We observed that responses of TDLNs to ICIs markedly differ from their paired primary lung tumors regarding the radiological, metabolic (18F-FDG uptake), and pathologic alterations. Neoadjuvant ICIs therapy specifically decreased 18F-FDG-reflected metabolic activity in the primary tumor beds with pCR/MPR but not their TDLNs counterparts. Furthermore, the presence of invaded TDLNs was associated with poor pathologic responses in the matched primary tumor beds and predictive of rapid post-treatment tumor relapse. Spatial profiling demonstrated exclusion of T cell infiltrates within the metastatic lesions of invaded TDLNs, and diminished multiple immune and non-immune compositions in non-involved regions surrounding the metastatic lesions. INTERPRETATION: These results provide the first clinically-relevant evidence demonstrating unique response patterns of TDLNs under ICIs treatment and revealing the underappreciated association of TDLNs status with the response of their paired primary tumors to ICIs in lung cancer. FUNDING: This work was supported by the National Natural Science Foundation of China (82072570 to F. Yao; 82002941 to B. Sun), the excellent talent program of Shanghai Chest Hospital (to F.Y), the Basic Foundation Program for Youth of Shanghai Chest Hospital (2021YNJCQ2 to H.Yang), and the Innovative Research Team of High-level Local Universities in Shanghai (SHSMU-ZLCX20212302 to F. Yao).