Facility-Level Disparities in Radiation Use for Limited-Stage Small Cell Lung Cancer.

Purpose: Treatment of limited-stage small cell lung cancer (LS-SCLC) with twice-a-day radiation therapy (RT) has remained the standard of care for many decades. Growing evidence suggests that outcomes with dose escalated twice-a-day RT may further improve outcomes. However, once-daily treatment remains common. The purpose of this study was to evaluate individual treatment facilities for utilization of twice-a-day RT.

Methods: Patients with LS-SCLC treated with definitive chemoradiation from 2004 to 2019 were identified in the National Cancer Database. RT was classified as twice-a-day (45 Gy in 30 fractions) or once-daily (59.4-70.2 Gy in 30-39 fractions). Patients were excluded if surgery was performed. All patients received doublet chemotherapy. Unique treatment facilities delivering at least one twice-a-day treatment course during the study period were classified as BID-treating. Facilities not delivering any twice-a-day RT were classified as QD-only. The proportion of QD-only facilities was identified. Facility-level characteristics associated with QD-only classification were analyzed.

Results: A total of 22,362 patients with LS-SCLC were treated at 1,222 unique facilities. A slight majority of facilities (n = 644, 52.7%) were BID-treating, whereas fewer (n = 578, 47.3%) were QD-only. A total of 73.9% of academic facilities were BID-treating versus 48.3% of nonacademic facility types (P < .001). Only 20.7% of low volume treatment facilities (lowest quartile of patients with LS-SCLC treated) used twice-a-day fractionation versus 78.2% of the highest quartile volume facilities (P < .001). On multivariable analysis, academic and high-volume facilities were statistically significantly associated with BID-treating classification (adjusted odds ratio, 2.5 [P < .001] and 4.2 [P < .001], respectively).

Conclusion: Nearly half of facilities treating LS-SCLC with definitive chemoradiation do not use twice-a-day fractionation schedules despite ongoing and growing evidence of superiority to once-daily fractionation. High-volume, academic facilities were more likely to offer twice-a-day fractionation.