Efficacy and safety of stereotactic radiotherapy in oligometastases

Distant metastasis remains a leading cause of treatment failure in patients with cancer. While salvage treatments such as surgery, targeted therapy, and immunotherapy provide some benefits, they have inherent limitations. This study examines the efficacy and safety of stereotactic radiotherapy (SRT) in managing oligometastatic tumors. We retrospectively analyzed data from 96 patients with oligometastatic tumors who were treated with SRT at the Department of Radiotherapy of the First Affiliated Hospital of Guangxi Medical University between September 2019 and March 2023. Descriptive statistics were used to analyze patient characteristics, tumor response, and survival outcomes, whereas a single-sample ratio test was used to compare SRT efficacy across different tumor sites. Kaplan–Meier analysis was used to determine progression-free survival (PFS) and overall survival (OS). Three months post-treatment, the complete response, partial response, stable disease, and progressive disease rates were 26.32%, 50.00%, 21.05%, and 2.63% for liver oligometastases; 0.00%, 39.13%, 43.48%, and 17.39% for lung oligometastases; and 8.57%, 62.86%, 25.71%, and 2.86% for brain oligometastases, respectively. The objective response rate was 65.62%, and the disease control rate was 93.75%. The median PFS was 18 months, and the median OS was 27 months. The primary lesions were mainly located in the liver and lungs. Compared with previous studies where stereotactic ablative body radiotherapy achieved a median OS of 16 months for liver metastases and surgery yielded an OS of 7 – 24 months for non-small cell lung cancer with brain metastases, our SRT outcomes were significantly improved. Adverse events (≥grade 3), primarily hematological toxicity, occurred in only 5.21% of patients. SRT was both effective and well-tolerated among patients with oligometastatic tumors, offering a promising treatment option.