Potential benefit of dose-escalated stereotactic body radiation therapy using CyberKnife for early-stage primary lung cancer

Abstract

Introduction: The study aimed to evaluate the efficacy and safety of dose-escalated stereotactic body radiotherapy (SBRT) for primary lung cancer.

Methods: Patients with peripherally located T1-2N0M0 primary lung cancer who underwent SBRT from April 2013 to December 2019 were included. Group A received 60 Gy in five fractions with CyberKnife prescribed at 99% gross tumor volume. Group B received 48 Gy in four fractions by a gantry-mounted linear accelerator, with isocenter prescription. Cumulative incidence of local failure (LF), progression free survival (PFS), overall survival (OS), and toxicity were retrospectively compared.

Results: Groups A and B comprised 39 and 36 patients, respectively. Group A had more patients without histological confirmation (p < .001) and showed lower V20 of bilateral lungs (p = .025). The median follow-up duration of Group A and B was 22.0 and 21.5 months, respectively, and the 2-year cumulative incidence of LF, PFS, and OS were .0% versus 11.6% (p = .065), 66.2% versus 62.7% (p = .694), 84.1% versus 81.1% (p = .827), respectively. There was no difference in Grade ≥ 2 toxicity rate between Groups A and B (7.7% vs. 11.1%; p = .704).

Conclusion: Dose-escalated SBRT using CyberKnife showed reduced lung dose and potential benefits for improved local control with comparable toxicity.

Keywords: CyberKnife; dose escalation; nonsmall cell lung cancer; stereotactic body radiation therapy; tumor.