Incidental Mediastinal Nodal Radiation During Stereotactic Radiation for Lung Tumors: Implications for High-dose Treatment of Locally Advanced Disease

Stereotactic Body Radiation Therapy Versus Nonradiotherapeutic Ablative Procedures (Laser/Cryoablation and Electrocautery) for Early-Stage Non-Small Cell Lung Cancer

BACKGROUND

Despite the fact that stereotactic body radiation therapy (SBRT) is the only recommended first-line therapy for inoperable early-stage non-small cell lung cancer (NSCLC), several thermal ablative procedures (TAPs; defined herein as laser/cryoablation and electrocautery) are available. Studies showing outcomes of these procedures and how they compare with SBRT are scarce. We sought to evaluate the comparative efficacy of SBRT versus TAPs using the National Cancer Database (NCDB).

METHODS

The NCDB was queried for patients with early-stage NSCLC who did not undergo surgical resection. Treatment-specific inclusion criteria were applied to select for patients receiving either TAPs or SBRT. Univariate logistic regression and Cox proportional hazards modeling were performed, and Kaplan-Meier curves were generated. Serial propensity matches were performed using a modified greedy 8→n matching 1:1 algorithm.

RESULTS

A total of 27,734 patients were analyzed; 26,725 underwent SBRT and 1,009 underwent TAPs. Patients who received SBRT were older and more likely to have clinical stage IB (vs IA) disease. Despite this, SBRT was associated with longer median overall survival (mOS; 37.7 vs 33.5 months; P=.001) and 1-, 2-, and 5-year OS rates compared with the TAPs cohort (86.7% vs 83.1%, 67.5% vs 62.7%, and 30.6% vs 26.9%, respectively; P=.001). Upon propensity matching, improved OS with SBRT remained, with a mOS of 40.4 versus 33.4 months and 1-, 2-, and 5-year OS rates of 89.0% versus 82.9%, 69.7% versus 62.7%, and 34.4% versus 26.4%, respectively (P=.003).

CONCLUSIONS

Despite being associated with more higher-risk factors, SBRT was associated with higher OS compared with TAPs for treatment of nonoperative patients diagnosed with early-stage NSCLC. However, causation cannot be implied owing to the inherent limitations of large heterogeneous datasets such as the NCDB.