Stereotactic body radiotherapy with a high maximum dose improves local control, cancer-specific death and overall survival in peripheral early-stage non-small cell lung cancer.

ABSTRACT Purpose We investigated whether delivery of a high biologically effective dose (BED) to primary tumors affects systemic outcomes of cancer-specific death (CSD) and overall survival (OS) rates following stereotactic body radiotherapy (SBRT) in patients with early-stage non-small cell lung cancer (ES-NSCLC). Patients and methods Among consecutive ES-NSCLC patients treated with SBRT between 2005 and 2019, we retrospectively identified patients who received a prescription of 50–60 Gy/5 fractions with maximum doses of 62.5-100 Gy. Patients were categorized by maximum BED within the planning target volume with a threshold dose of 200 Gy. Outcomes were analyzed in all and matched patients. Results Overall, 433 patients were eligible, and 262 and 171 patients were categorized into HighBED- and LowBED-groups, respectively. After propensity score matching, pairs of 154 patients were selected. Median follow-up times for the HighBED- and LowBED-groups were 52.3 months (range, 0.8-107.2 months) and 121.6 months (range, 3.0-162.8 months), respectively. The local recurrence rate in the HighBED-group was significantly lower than that in the LowBED-group (5 years rate, 1.3% and 7.2%; hazard ratio (HR), 0.15; 95% CI, 0.03 to 0.65; p=.011). Rates of any recurrence and CSD in the HighBED-group were significantly lower (any recurrence: 5 years rate; 18.1% and 32.1%; HR, 0.52; 95% CI, 0.33 to 0.83; p=.0058; CSD: 5 years rate, 9.5% and 21.8%; HR, 0.38; 95% CI, 0.20 to 0.70; p=.002) and OS in the HighBED-group was significantly better compared with the LowBED-group (5 years rate, 61.7% and 51.8%; HR, 0.71; 95% CI, 0.50 to 1.00; p=.047). Conclusion In patients with peripheral ES-NSCLC, SBRT with a high maximum dose may improve not only local control, but also any recurrence, CSD, and OS rates without increased toxicity. Further trials designed to evaluate whether higher-intensity SBRT increases local control rates and contributes to improved CSD and OS outcomes are anticipated.