Radiosurgery and fractionated stereotactic radiotherapy in oligometastatic/oligoprogressive non-small cell lung cancer patients: Results of a multi-institutional series of 198 patients treated with “curative” intent

Objectives: stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) are a therapeutic option for Oligometastatic/Oligoprogressive (OM/OP) NSCLC. This retrospective multicentre analysis aims to analyse clinical outcomes and treatment related toxicity of patients treated to all sites of know disease with SRS and/or FSRT for OM/OP NSCLC in 8 Italian radiation oncology centres. Materials and methods: From January 2016 to January 2017 198 OM/OP NSCLC patients (pts) were treated in 8 Centres. Inclusion criteria were as follows: 1–5 lesions at onset or after previous systemic treatment; Pts must have all metastatic lesions treated. Endpoints analysed were local progression free survival (LPFS); out-of-field recurrence free survival (OFPS); progression free survival (PFS); overall survival (OS). Time to New systemic Therapy free survival (TNT) and toxicity were also analysed. Results: At the time of radiotherapy, 119 pts (60 %) were treated for a single lesion, 49 (25 %) for 2 lesions, 30 (15 %) for 3–5 metastases. Total number of lesions treated was 333: 204 brain, 68 lung, 24 bone, 16 nodal, 12 adrenal, 8 liver and 1 soft tissue. 83/198 pts (41.8 %) had the primary tumour controlled at the time of the SRT. After a median follow-up of 18 months, median OS and PFS were 29.6 months and 10.6 months, respectively. One year LPFS and OPFS were 90 % and 47 %, respectively. Median TNT was 10 months. At univariate analysis factors associated with better OS were PS 0–1; controlled primary tumour, 1–2 lesions; extracranial metastasis. Multivariate analysis confirmed number of lesions