Retrospective cohort study of consolidative hypofractionated radiotherapy for oligometastatic non-small lung cancer

A retrospective cohort study at Kyungpook National University (Daegu, South Korea) evaluated efficacy and safety of consolidative hypofractionated radiotherapy for oligometastatic non-small cell lung cancer (NSCLC). The study included 216 patients with oligometastatic NSCLC treated with consolidative hypofractionated radiotherapy (biological effective dose ≥ 50 Gy, < 10 fractions). Patients were classified as having ‘genuine’ or ‘induced’ oligometastatic disease (OMD) according to ESTRO/EORTC criteria. The median patient age was 73 years. At a median follow-up of 1.8 years, the 1-year rates of local control (LC), progression-free survival (PFS), and overall survival (OS) were 88.7%, 51.2%, and 79.7%, respectively. Median PFS was 1.0 year and median OS was 2.6 years. In multivariable analysis, ‘induced” OMD was an independent predictor of worse LC (HR 2.546; p=0.001) and PFS (HR 1.863; p<0.001) compared to ‘genuine’ OMD. Radiotherapy parameters, including gross tumor volume and biological effective dose, were not significantly associated with survival outcomes. Grade 3 radiation pneumonitis occurred in 1.8% of patients; no grade 4 or 5 toxicities were observed. The authors conclude that consolidative hypofractionated radiotherapy is safe and effective for patients with oligometastatic NSCLC, including elderly patients. The OMD classification system provides superior prognostic value over technical radiotherapy parameters.