000K utf8 1100 2021$c2021-09-15 1500 eng 2050 urn:nbn:de:hbz:465-20240905-120759-2 2051 10.1186/s13014-021-01904-4 3000 Guberina, Maja 3010 Aigner, Clemens 3010 Darwiche, Kaid 3010 Eberhardt, Wilfried E. E. 3010 Gauler, Thomas 3010 Guberina, Nika 3010 Hautzel, Hubertus 3010 Herrmann, Ken 3010 Karpf-Wissel, Rüdiger 3010 Metzenmacher, Martin 3010 Ploenes, Till 3010 Pöttgen, Christoph 3010 Schuler, Martin 3010 Stuschke, Martin 3010 Theegarten, Dirk 3010 Umutlu, Lale 3010 Wiesweg, Marcel 4000 Patterns of nodal spread in stage III NSCLC$dimportance of EBUS-TBNA and 18 F-FDG PET/CT for radiotherapy target volume definition [Guberina, Maja] 4209 Purpose: The aim of this study was to compare the pattern of intra-patient spread of lymph-node (LN)-metastases within the mediastinum as assessed by 18F-FDG PET/CT and systematic endobronchial ultrasound-guided transbronchial-needle aspiration (EBUS-TBNA) for precise target volume definition in stage III NSCLC. Methods: This is a single-center study based on our preceding investigation, including all consecutive patients with initial diagnosis of stage IIIA-C NSCLC, receiving concurrent radiochemotherapy (12/2011-06/2018). Inclusion criteria were curative treatment intent, 18F-FDG PET/CT and EBUS-TBNA prior to start of treatment. The lymphatic drainage was classified into echelon-1 (ipsilateral hilum), echelon-2 (ipsilateral LN-stations 4 and 7) and echelon-3 (rest of the mediastinum, contralateral hilum). The pattern of spread was classified according to all permutations of echelon-1, echelon-2, and echelon-3 EBUS-TBNA findings. Results: In total, 180 patients were enrolled. Various patterns of LN-spread could be identified. Skip lesions with an involved echelon distal from an uninvolved one were detected in less than 10% of patients by both EBUS-TBNA and PET. The pattern with largest asymmetry was detected in cases with EBUS-TBNA- or PET-positivity at all three echelons ( p < 0.0001, exact symmetry test). In a multivariable logistic model for EBUS-positivity at echelon-3, prognostic factors were PET-positivity at echelon-3 (Hazard ratio (HR) = 12.1; 95%-CI: 3.2 - 46.5), EBUS-TBNA positivity at echelon-2 (HR = 6.7; 95%-CI: 1.31–31.2) and left-sided tumor location (HR = 4.0; 95%-CI: 1.24 - 13.2). There were significantly less combined ipsilateral upper (LN-stations 2 and 4) and lower (LN-station 7) mediastinal involvements (16.8% of patients) with EBUS-TBNA than with PET (38.9%, p < 0.0001, exact symmetry test). EBUS-TBNA detected a lobe specific heterogeneity between the odds ratios of LN-positivity in the upper versus lower mediastinum ( p = 0.0021, Breslow-Day test), while PET did not (p = 0.19). Conclusion: Frequent patterns of LN-metastatic spread could be defined by EBUS-TBNA and PET and discrepancies in the pattern were seen between both methods. EBUS-TBNA showed more lobe and tumor laterality specific patterns of LN-metastases than PET and skipped lymph node stations were rare. These systematic relations offer the opportunity to further refine multi-parameter risk of LN-involvement models for target volume delineation based on pattern of spread by EBUS-TBNA and PET. 4950 https://doi.org/10.1186/s13014-021-01904-4$xR$3Volltext$534 4950 https://nbn-resolving.org/urn:nbn:de:hbz:465-20240905-120759-2$xR$3Volltext$534 4961 https://duepublico2.uni-due.de/receive/duepublico_mods_00077582 5051 610 5550 18F-FDG PET/CT 5550 EBUS-TBNA 5550 Lymphatic drainage 5550 NSCLC 5550 Pattern of spread 5550 Radiation 5550 Stage III