Abstract
ObjectivesLymph node staging in patients with non-small cell lung cancer is crucial for determining prognosis and treatment. Our objective was to evaluate the clinical- to pathological agreement of guideline-concordant nodal staging in patients with resectable NSCLC and assess occurrence and distribution of occult lymph node metastases (OLM). Materials and methodsIn a retrospective single center cohort study (n = 390), we analyzed all surgically treated NSCLC patients from January 2015 until April 2019. Patients were classified into sub-groups (1) mediastinal staging by PET-CT/CT-scan (IMAGE-group) or (2) invasive staging by endobronchial ultrasound and mediastinoscopy (INVAS-group). Agreement between final clinical (cN) and pathological nodal stage (pN) and the presence and location of OLM are analyzed. ResultsAgreement between cN- and pN-stage was 86.3 % in the IMAGE-group (n = 117) and 50.9 % in the INVAS-group (n = 167). Occult N1 disease was found in 33 patients (16.6 % in cN0) of which 52 % occurred in LN-regions 12−14. Occult N2 disease was found in 20 cases (6.5 % in cN0 and 12.7 % in cN1). Combined, 23.1 % of all pre-operatively cN0-staged patients (n = 46/199) had OLM (pN+), of which 12.1 % (24/199) had metastases in regions 5–6 and/or 12−14. Of all patients with OLM, 50.0 % (23/46) had primary tumors ≤30 mm. ConclusionOLM are frequently identified in clinically N0/N1 NSCLC, also in tumors <3 cm, and often in regions beyond reach of current staging techniques. These findings should be addressed when non-surgical treatment or sub-lobar resections are considered for early stage lung cancer.
Highlights
Non-small cell lung cancer (NSCLC) is the most commonly diagnosed type of lung cancer and one of the leading causes of cancer-related deaths worldwide [1]
All patients with a suspected or proven NSCLC in the Radboudumc routinely receive diagnostic and staging work-up according to ACCP and ESTS guidelines and multi-disciplinary team (MDT) decision-making, with the exception being that our pulmonary nodule diagnostic pro gram routinely includes an endobronchial ultrasound (EBUS) evaluation in combination with a navigation bronchoscopy, irrespective of PET/computed tomography (CT) findings and despite the limited tumor size in this subgroup [32]
Additional invasive staging by EBUS was performed in 167 patients (INVAS-group)
Summary
Non-small cell lung cancer (NSCLC) is the most commonly diagnosed type of lung cancer and one of the leading causes of cancer-related deaths worldwide [1]. For patients with a clinical suspicion or higher a priori probability of lymph node involvement, invasive mediastinal staging including endobronchial ultrasound (EBUS) with fine needle aspiration (FNA) ideally combined with esophageal ultrasound (EUSb or EUS) is recommended [4,5,7]. If these results are negative, but suspicion remains high, a (video-assisted) mediastinoscopy is further recom mended [4,6,8]. Despite this advanced diagnostic algorithm, occult lymph node metastases (OLM) and therewith post-operative upstaging remain a problem and raise the question whether our current nodal staging techniques and standards are of sufficient accuracy [9,10]
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