Real world outcomes in patients with lung oligometastases treated with SABR - a single-centre experience

Abstract

Introduction: Delivering Stereotactic Ablative Body Radiotherapy (SABR) to patients with extracranial oligometastatic disease has the potential to improve long-term disease control, survival and defer changes to systemic therapies [1]. We present the results from an audit of patients treated with SABR under the NHS Commissioning through Evaluation (CtE) scheme at The Christie Hospital, Manchester UK. Methods: The outcomes of patients who received SABR to lung lesions or thoracic nodes under CtE were analysed. Prescribed doses included 30-60Gy in 3-8 fractions to nodes and 54-60 Gy in 3-8 fractions to lung lesions. Patients were eligible if aged ≥18, had ≤3 metastatic lesions, WHO performance status of ≤2, onset of metastatic disease was ≥6 months from the primary tumour diagnosis and life expectancy estimated to be ≥6 months. The main outcomes evaluated included local control (assessed by local radiologists) and overall survival which were obtained from hospital records. Adverse events by CTCAE grade were recorded prospectively. Results: 52 patients treated between February 2016 and August 2019 were included. Median follow up was 28.5 months and median age was 72 (range 49-90 years). 51.9% were female and 75% had a performance status of 0-1. The most common primary was colorectal (n=23; (44.2%)). 5 patients received SABR to thoracic nodes, and 8 patients had >1 lesion treated. The median BED10 dose was 121 Gy. Local control was 96% at 1 year and 84.6% at 2 years. Overall survival was 94.2% at 1 year and 89.7% at 2 years. One patient had a toxicity graded ≥3, which was fatigue. Conclusion: The findings demonstrate high levels of local control and overall survival in these patients, with low rates of toxicity. Our findings are comparable to the overall national results, and SABR to oligometastatic lesions has now been commissioned.