Stereotactic body radiation therapy versus conventionally fractionated radiation therapy for early stage non-small cell lung cancer

Purpose: To date, no published randomized trials have shown stereotactic body radiation therapy (SBRT) to offer superior outcomes to conventionally fractionated radiation therapy (CFRT) for early-stage non-small cell lung cancer (NSCLC). The largest study to date, this investigation of a contemporary national database sought to evaluate practice patterns and survival between CFRT and SBRT. Methods: The National Cancer Database was queried (2004–2015) for histologically-confirmed cT1-2aN0M0 NSCLC undergoing definitive CFRT or SBRT. Multivariable logistic regression ascertained factors associated with SBRT administration. Kaplan–Meier analysis evaluated overall survival (OS) before and following propensity matching. Cox proportional hazards modeling determined variables associated with OS. Results: Of 23,088 patients, 2286 (10%) patients received CFRT and 20,802 (90%) SBRT. SBRT was less often delivered in African-Americans, patients with lower incomes, urban location, greater comorbidities, at non-academic centers, in larger tumors, and squamous histology (p < 0.05 for all). Patients treated with SBRT had a higher median OS (38.8 months vs. 28.1 months, p < 0.001). At median follow-up of 44.6 months, the median OS for the SBRT group was 38.8 months, versus 28.1 months for CFRT (p < 0.001). These findings persisted following propensity matching. Subgroup analyses demonstrated improved OS in multiple subcohorts (T2, Charlson comorbidity score 2–3, squamous histology). SBRT was also independently associated with OS on Cox multivariate analysis (p < 0.001). Conclusions: The largest such study to date (comprising of over 23,000 patients), this investigation demonstrates the survival benefit to ablative radiotherapy for early-stage NSCLC. Maturation of comparative prospective trials is eagerly awaited.