Treatment Outcomes and Toxicities of Stereotactic Body Radiotherapy for Oligoprogressive Metastatic Non–Small-Cell Lung Cancer

Introduction:This study reviewed the toxicities and outcomes of stereotactic body radiotherapy (SBRT) for oligoprogressive metastatic non-small-cell lung cancer (NSCLC).Methods: The cases of patients with oligoprogressive NSCLC receiving SBRT from 2015 to 2020 were reviewed retrospectively.Demographics were analysed by descriptive statistics.Important treatment outcomes including local control and survival were analysed by the Kaplan-Meier method.Simple and multivariable Cox regression analyses were carried out to investigate prognostic factors.Toxicities were reported using the Common Terminology Criteria for Adverse Event version 4.0.Results: Forty-one cases with 51 oligoprogressive sites were included.The median age of the cohort was 65 years.The most commonly ablated sites were the lung (68.6%) and bone metastasis (17.6%).The most common driver mutation was the epithelial growth factor receptor mutation (85%).SBRT doses ranged from 30 to 60 Gy in 3 to 10 fractions.Median follow-up time was 64 weeks.SBRT achieved a 1-year local control rate of 85%.Median progression-free survival (PFS) after SBRT was 8.8 months and median time from SBRT to the next line of systemic treatment was 9 months.A robust response to pre-SBRT systemic treatment was significantly associated with longer PFS after SBRT.Median overall survival was 58 months.There was one case of grade 3 pneumonitis (2%) and one case of rib fracture (2%).Conclusion: SBRT for oligoprogression in NSCLC is an effective strategy to prolong the time to the next systemic treatment with minimal toxicities.