International Patterns of Practice for Stereotactic Ablative Radiotherapy for Early-Stage Non-Small Cell Lung Cancer: Are We All in Sync?: Global patterns of practice for SABR for early-stage NSCLC.

Purpose: To generate an understanding of the similarities and variations in international practice patterns for stereotactic ablative radiotherapy (SABR) in early-stage non-small cell lung cancer (NSCLC).

Methods: An online survey was conducted from October to December 2023, addressing general clinical and technical considerations for lung SABR, and for 5 specific anatomical NSCLC locations (peripheral, abutting chest wall, near brachial plexus, central, and ultra-central). Invitations to participate were extended through email and were distributed on social media.

Results: The survey was completed by 255 radiation oncologists, each representing a single institution across 51 countries. Respondents reported treating a median of 20 cases annually. A total of 38% of participants reported using single-fraction SABR, and 54% applied an upper limit on the maximum dose (Dmax). Among those who applied a Dmax limit, 58% reported a Dmax threshold at ≥130% of the prescription, though this limit varied by region and national economy status. Respondents from low- and middle-income countries were less likely to set a Dmax limit at ≥130% (30% vs. 66%, p < 0.01) and less likely to use single-fraction SABR (14% vs. 44%, p < 0.01). Higher annual SABR patient volumes were associated with higher Dmax adoption (г = 0.23, p < 0.01). Across the 5 clinical scenarios presented; 57 distinct dose regimens were recommended. The most common regimen in each scenario was: 54 Gy in 3 fractions for peripheral tumors, 50 Gy in 5 fractions for apical, central, and abutment of chest wall, and 60 Gy in 8 fractions for ultra-central tumors. Approximately two-thirds of practices recommend a biologically effective dose (BED₁₀) <100 Gy for one or more anatomical sites.

Conclusion: The findings reveal considerable variation in global SABR practice. These differences highlight the need for further data to guide prescription practices, and an international experts' consensus may be beneficial to standardize practice.