Stereotactic Body Radiation Therapy 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 after stereotactic body radiation therapy (SBRT) in patients with early-stage non-small cell lung cancer (ES-NSCLC).

Methods and materials: Among consecutive ES-NSCLC patients treated with SBRT between 2005 and 2019, we retrospectively identified patients who received a prescription of 50 to 60 Gy in 5 fractions with maximum doses of 62.5 to 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-year rate, 1.3% and 7.2%; hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.03-0.65; P = .011). Rates of any recurrence and CSD in the HighBED group were significantly lower (5-year any recurrence: 18.1% and 32.1%; HR, 0.52; 95% CI, 0.33-0.83; P = .0058; 5-year CSD: 9.5% and 21.8%; HR, 0.38; 95% CI, 0.20-0.70; P = .002), and OS in the HighBED group was significantly better compared with the LowBED group (5-year rate: 61.7% and 51.8%; HR, 0.71; 95% CI, 0.50-1.00; 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.