A risk stratification model based on lymph node characteristics has been observed to confirm a lack of lung cancer in lymph nodes adequately sampled with endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and classified as negative.
Researchers from the University Hospital of South Manchester (UK) examined 329 lymph nodes that were classified as EBUS-TBNA negative from patients with pathologically diagnosed or, in a limited number, clinically diagnosed lung cancer. A total of 196 lymph nodes were used to derive a lymph node radiologic and ultrasound characteristic-based model, designed to determine risk for actually being positive for lung cancer upon further evaluation. The remaining 133 lymph nodes were subsequently used for validation.
Results of this study, published in the Journal of Thoracic Oncology, demonstrated that lymph nodes categorized as low risk according to the model had 98 and 99% chances of actually being negative based on the validation and derivation sets, respectively. Lymph nodes categorized as at high risk of being truly malignant by the model were 65% in both the validation and derivation sets following a false negative EBUS-TBNA classification.
Discussing their work, the authors stated: “Radiological staging will never replace pathological staging, but in cases of negative or inadequate EBUS-TBNA sampling our study demonstrates that the combination of radiologic and ultrasound data post-test can stratify patients into low and high risk for nodal malignancy. This risk stratification model provides a mechanism for lung cancer multidisciplinary teams to discuss the risk of false negative EBUS-TBNA sampling, which may ultimately assist in the decision-making process for either further staging procedures or direct progression to treatment”.
Sources: Evison M, Morris J, Martin J et al. Nodal staging in lung cancer: A risk stratification model for lymph nodes classified as negative by EBUS-TBNA. J Thorac Oncol doi:10.1097/JTO.0000000000000348 (2014) (Epub ahead of print); International Association for the Study of Lung Cancer press release