Photo Credit: Md Babul Hosen

The following is a summary of “Systematic endoscopic staging of the mediastinum to guide radiotherapy planning in patients with locally advanced non-small-cell lung cancer (SEISMIC): an international, multicentre, single-arm, clinical trial,” published in the March 2024 issue of Pulmonology by Steinfort et al.

Systematic mediastinal lymph node staging through endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) significantly enhances staging accuracy in patients with early-stage non-small-cell lung cancer (NSCLC). Despite this, individuals with locally advanced NSCLC often undergo selective lymph node sampling, potentially overlooking occult metastases. This international, multicenter, single-arm study aimed to assess the incidence of PET-occult lymph node metastases detected by systematic endoscopic mediastinal staging and explore its impact on radiotherapy planning in patients with locally advanced NSCLC. Conducted across seven tertiary lung cancer centers in four countries, the study included patients aged 18 years or older with suspected or confirmed locally advanced NSCLC. 

The primary endpoint was the detection rate of PET-occult mediastinal lymph node metastases following systematic endoscopic staging. Of the 155 eligible participants, 37% exhibited discrepancies between PET and EBUS-TBNA findings, with PET-occult lymph node metastases identified in 12% of patients, including those with clinical stage IIIA or cN2 disease. Notably, detecting PET-occult disease led to significant modifications in treatment plans for all affected patients. In silico dosimetry analyses revealed suboptimal tumor coverage with standard PET-based radiotherapy planning. These results underscore the importance of routine systematic endoscopic mediastinal staging in locally advanced NSCLC patients undergoing radiotherapy, facilitating more accurate treatment planning and decision-making processes.

Source: sciencedirect.com/science/article/abs/pii/S2213260024000109