FDG-PET/CT for pretherapeutic lymph node staging in non-small cell lung cancer: A tailored approach to the ESTS/ESMO guideline workflow

• Published in: Lung cancer (Amsterdam, Netherlands) Netherlands), 2021-07, Vol.157, p.66-74
• Main Authors: Rogasch, Julian M.M., Frost, Nikolaj, Bluemel, Stephanie, Michaels, Liza, Penzkofer, Tobias, von Laffert, Maximilian, Temmesfeld-Wollbrück, Bettina, Neudecker, Jens, Rückert, Jens-Carsten, Ochsenreither, Sebastian, Böhmer, Dirk, Amthauer, Holger, Furth, Christian
• Format: Article
• Language: English
• Subjects: Accuracy; FDG-PET/CT; Guideline; Mediastinal lymph nodes; Non-small cell lung cancer
• ISSN: 0169-5002; 1872-8332
• DOI: 10.1016/j.lungcan.2021.05.003

•Risk factors for missed pN2 defined by current guidelines may be overcautious.•In current analysis, missed pN2 was always associated with adenocarcinoma subtype.•Most EBUS-TBNA procedures in patients with mediastinal negative PET/CT were confirmatory.•The proposed modified workflow could have avoided 82 % of these procedures.•In this analysis, additional cases of missed pN2 disease would have remained rare. In patients with NSCLC, current ESTS and ESMO guidelines recommend invasive lymph node (LN) staging with EBUS-TBNA even if FDG-PET/CT is negative for mediastinal LNs if at least one of three risk factors is present (cN1, non-peripheral primary or primary >3 cm). Modified workflows to avoid unnecessary invasive procedures were evaluated. Monocentric retrospective analysis of pretherapeutic FDG-PET/CT in 247 patients with NSCLC (62 % male; age, 68 [43–88] years) using an analog or digital PET/CT scanner. PET windowing was standardized. LNs were positive if ‘LN uptake > mediastinal blood pool’ or short axis >10 mm. Surgery or EBUS-TBNA served as reference for diagnostic accuracy per LN station. In all patients with negative mediastinal LNs by PET/CT, LN histology from surgery was available. Among 700 L N stations analyzed, 180 were malignant. Sensitivity and specificity of PET/CT per LN station were 93 % and 71 %. Following current guidelines, 76 patients with mediastinal negative PET/CT required confirmatory invasive staging. Only 5/76 patients had unexpected pN2 (all had adenocarcinoma). In a modified approach, confirmatory invasive staging was confined to patients with mediastinal negative PET/CT who showed all three risk factors. Using this modification, EBUS-TBNA could have been omitted in 62 (82 %) of the 76 patients who required EBUS-TBNA based on current recommendation. Among these 62 patients, only one patient had unsuspected pN2 (single-level) while the remaining 61 of 62 omitted EBUS-TBNA were deemed unnecessary because mediastinal LNs were confirmed to be negative. No multi-level pN2 would have been missed. In the current analysis, 82 % of EBUS-TBNA procedures in patients with mediastinal negative PET/CT could have been omitted by modifying the current guideline workflow as proposed (i.e., restricting EBUS-TBNA in patients with cN0/1 to those with all three risk factors). This was consistent with different PET/CT scanners. Prospective confirmation is required.