Analysis of Efficacy and Safety of Body Gamma Knife Stereotactic Radiosurgery in Patients with Early- stage Non-small-cell Lung Cancer: A 10-Year Cohort Study

Abstract

Introduction: Stereotactic body radiotherapy is frequently used for treating non-operable early-stage non-small cell lung cancer . Body gamma knife stereotactic radiosurgery is a specialized SBRT technique established in China. Here, the long-term efficacy, failure pattern, and toxicity of γ-SRS for initial-phase NSCLC were evaluated through a cohort study, including a 10-year follow-up. Methods:To conduct this study, 29 patients with initial-phase NSCLC received γ-SRS treatment between 2007 and 2010. The prescribed doses for the Gross Target Volume (GTV), Clinical Target Volume (CTV), and Planning Target Volume (PTV) were 70, 60, and 50 gray (Gy), respectively, administeredin 10 fractions, with the creation of curves for the 50, 60, and 70% isodoses to cover 80, 90, and 100% of the GTV,CTV, and PTV, respectively. Patients underwent CT/PET-CT imaging at one, three, and six months post-treatment, followed by imaging every six months for two years, and later, annual examinations were conducted. Results:Patients were aged 71 years on average, the mean follow-up was 166 months, overall survival（OS）was 75 months, and the corresponding median progression-free survival (PFS) was 57 months. Moreover, the first, third, fifth, and ten-year OS rates were 93.1, 75.9, 65.5, and 34.9%, while the PFS rates were 86.2, 65.3, 43.6, and 27.7%. Only two patients (6.9%) had grade 3 treatment-associated adverse events（Pneumonia）, while grade 4 or 5 events were not reported. Conclusion:This study depicted the efficacy of γ-SRS for inoperable early-phase NSCLC patients or those who refused surgery. The primary patterns of failure outcomes were regional relapse and distant metastasis.