Indications For Invasive Mediastinal Staging In Patients With Early Non-Small Cell Lung Cancer Staged With Pet-Ct

Abstract Purpose/Objective(s) Appropriate use of invasive mediastinal staging in patients with clinically node-negative NSCLC staged by PET-CT is critical in selecting patients for curative-intent therapy such as surgery or SBRT, but little data exists to guide this decision-making. We examined a large population of patients with clinical stage I NSCLC referred for mediastinoscopy or EBUS to find risk factors for occult N2 lymph nodes and determine which patients benefit from invasive staging. Materials/Methods We identified consecutive clinical T1-2N0 NSCLC patients being evaluated for curative-intent therapy between 2011 and 2015. None had evidence of nodal disease by PET-CT; the endpoint was pathologic confirmation of occult N2 disease by EBUS or mediastinoscopy. Tumor size, location, histology, SUV max , and radiographic appearance were evaluated as determinants of occult N2 disease. Two group comparisons of continuous variables were done with independent t-tests and categorical variables were compared with χ 2 or Fisher’s exact test. Results In 284 patients with PET-CT-staged clinical T1-2N0 disease, the prevalence of occult N2 metastases was 7.0%. The negative predictive value of PET-CT was 92.9% and the negative predictive value of mediastinoscopy/EBUS was 96.3%. T2 tumors were more likely to have occult N2 disease than T1 tumors (11.8% v 3.6% p = 0.009). Pure solid tumors had greater involvement of N2 nodes than tumors with any ground glass component (12.6% v 3.1%, p  Conclusions Invasive mediastinal staging should be strongly encouraged in central tumors and solid T2 tumors because the risk of occult nodal involvement is greater than 10% in these cohorts. However, for patients with peripheral T1 tumors or peripheral T2 tumors with a significant ground glass component, the yield of invasive staging after a negative PET-CT is very low and invasive staging may not be warranted.