Pathologic Nodal Staging Before SBRT for Early-stage NSCLC Does Not Impact Overall Survival: A Propensity Score-matched NCDB Analysis.

Abstract

Stereotactic body radiation therapy (SBRT) for early-stage non-small cell carcinoma of the lung (NSCLC) is increasingly utilized. We sought to assess overall survival (OS) for early-stage NSCLC patients receiving SBRT depending on staging method. Early-stage NSCLC patients treated with definitive SBRT were identified in the National Cancer Database (NCDB), and OS was determined based on method of staging. Patient, disease, and treatment characteristics were also analyzed. A total of 12,106 patients were included; 865 (7%) received invasive staging (nodal sampling, NS) and 11,241 (93%) had no nodal sampling (NNS). From this larger dataset, a propensity score matching (1:1 without replacement) was performed, which yielded 839 patients for each group (NNS and NS). With a median follow-up time of 3.12 years, median survival for all patients included in the matched dataset was 2.75 years (95% CI: 2.55-2.93y), with 2- and 5-year OS estimated at 63.9% and 25.7%, respectively. In a multivariable analysis on matched data, there was no difference in mortality risk between the NNS and NS groups (hazard ratio=1.08, 95% CI: 0.94-1.24, P =0.25). Negative prognostic factors identified in the multivariable analysis of the matched data included: age more than 65, male sex, Charlson-Deyo Score ≥1, and tumor size ≥3cm. SBRT use in early-stage NSCLC steadily increased over the study period. Most patients proceeded to SBRT without nodal staging, conflicting with National Comprehensive Cancer Network (NCCN) guidelines which recommend pathologic mediastinal lymph node evaluation for all early-stage NSCLC cases, except stage IA. Our findings suggest similar OS in patients with early-stage NSCLC treated with SBRT irrespective of nodal staging. Furthermore, we highlight patient-related, disease-related, and treatment-related prognostic factors to consider when planning therapy for these patients.