The Impact of Preoperative Invasive Nodal Staging on Unexpected Mediastinal Upstaging in Early-Stage Non-small Cell Lung Cancer.

INTRODUCTION

Preoperative invasive nodal staging is standard of care for early-stage non-small cell lung cancer (NSCLC). Complications and delays in care are not negligible and diagnostic accuracy varies. In our system, invasive nodal staging is performed for clear radiographic indications (node > 1.0 cm short axis or standardized uptake value > 3.0, tumor > 4.0 cm). This study assessed whether unexpected mediastinal upstaging was less common in patients receiving preoperative invasive nodal staging.

METHODS

This retrospective study evaluated nodal upstaging, defined as pathological N2 or IIIA+ disease, based on receipt or non-receipt of invasive nodal staging. Clinical stage I-II NSCLC patients who underwent resection (2009-2019) were identified from our cancer registry. Stage and preoperative nodal staging information were confirmed through chart review. Associations between patient characteristics, invasive nodal staging receipt, and clinical to pathological stage changes were analyzed.

RESULTS

Among 2576 patients, 18.7% (n = 481) underwent invasive nodal staging. After resection, 6.2% of all patients had nodal upstaging and 24.9% had TNM upstaging. Only 0.3% (n = 9) were upstaged to N2 and 0.5% (n = 13) were upstaged to IIIA+. Lack of preoperative nodal sampling was not associated with N2 or IIIA+ upstaging. Findings were consistent in subanalyses of patients with surgical specimens meeting Commission on Cancer nodal sampling criteria and with clinical IB+ disease.

CONCLUSIONS

Although most patients did not undergo invasive nodal staging, <1% had unexpected N2 on surgical pathology. There was no association between lack of preoperative invasive nodal sampling and N2 nodal upstaging. Preoperative invasive nodal staging did not increase pathologic N2 nodal upstaging in early-stage NSCLC patients in our integrated health system.