Long-term Follow-up and Patterns of Recurrence of Patients With Oligometastatic NSCLC Treated With Pulmonary SBRT.

INTRODUCTION: This multicenter study aims to analyze outcome as well as early versus late patterns of recurrence following pulmonary stereotactic body radiotherapy (SBRT) for patients with oligometastatic non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: This analysis included 301 patients with oligometastatic NSCLC treated with SBRT for 336 lung metastases. Although treatment of the primary tumor consisted of surgical resection, radiochemotherapy, and/or systemic therapy, pulmonary oligometastases were treated with SBRT. RESULTS: The median follow-up time was 16.1 months, resulting in 2-year overall survival (OS), local control (LC), and distant control (DC) of 62.2%, 82.0%, and 45.2%, respectively. Multivariate analysis identified age (P = .019) and histologic subtype (P = .028), as well as number of metastatic organs (P < .001) as independent prognostic factors for OS. LC was superior for patients with favorable histologic subtype (P = .046) and SBRT with a higher biological effective dose at isocenter (P = .037), whereas DC was inferior for patients with metastases in multiple organs (P < .001) and female gender (P = .027). Early (within 24 months) local or distant progression was observed in 15.3% and 36.5% of the patients. After 24 months, the risk of late local failure was low, with 3- and 4-year local failure rates of only 4.0%, and 7.6%. In contrast, patients remained at a high risk of distant progression with 3- and 4-year failure rates of 13.3% and 24.1%, respectively, with no plateau observed. CONCLUSION: SBRT for pulmonary oligometastatic NSCLC resulted in favorable LC and promising OS. The dominant failure pattern is distant with a continuously high risk of disease progression for many years.

Influence of Institutional Experience and Technological Advances on Outcome of Stereotactic Body Radiation Therapy for Oligometastatic Lung Disease.

PURPOSE: Many technological and methodical advances have made stereotactic body radiotherapy (SBRT) more accurate and more efficient during the last years. This study aims to investigate whether experience in SBRT and technological innovations also translated into improved local control (LC) and overall survival (OS). METHODS AND MATERIALS: A database of 700 patients treated with SBRT for lung metastases in 20 German centers between 1997 and 2014 was used for analysis. It was the aim of this study to investigate the impact of fluorodeoxyglucose positron-emission tomography (FDG-PET) staging, biopsy confirmation, image guidance, immobilization, and dose calculation algorithm, as well as the influence of SBRT experience, on LC and OS. RESULTS: Median follow-up time was 14.3 months (range, 0-131.9 months), with 2-year LC and OS of 81.2% (95% confidence interval [CI] 75.8%-85.7%) and 54.4% (95% CI 50.2%-59.0%), respectively. In multivariate analysis, all treatment technologies except FDG-PET staging did not significantly influence outcome. Patients who received pre-SBRT FDG-PET staging showed superior 1- and 2-year OS of 82.7% (95% CI 77.4%-88.6%) and 64.8% (95% CI 57.5%-73.3%), compared with patients without FDG-PET staging resulting in 1- and 2-year OS rates of 72.8% (95% CI 67.4%-78.8%) and 52.6% (95% CI 46.0%-60.4%), respectively (P=.012). Experience with SBRT was identified as the main prognostic factor for LC: institutions with higher SBRT experience (patients treated with SBRT within the last 2 years of the inclusion period) showed superior LC compared with less-experienced centers (P≤.001). Experience with SBRT within the last 2 years was independent from known prognostic factors for LC. CONCLUSION: Investigated technological and methodical advancements other than FDG-PET staging before SBRT did not significantly improve outcome in SBRT for pulmonary metastases. In contrast, LC was superior with increasing SBRT experience of the individual center.

Stereotactic body radiotherapy (SBRT) for medically inoperable lung metastases-A pooled analysis of the German working group "stereotactic radiotherapy".

OBJECTIVES: The current literature on stereotactic body radiotherapy (SBRT) for oligometastatic disease is characterized by small patient cohorts with heterogeneous primary tumors, metastases location and dose regimes. Hence, this study established a multi-institutional database of 700 patients treated with SBRT for pulmonary metastases to identify prognostic factors influencing survival and local control. MATERIALS AND METHODS: All German radiotherapy departments were contacted and invited to participate in this analysis. A total number of 700 patients with medically inoperable lung metastases treated with SBRT in 20 centers between 1997 and 2014 were included in a database. Primary and metastatic tumor characteristics, treatment characteristics and follow-up data including survival, local control, distant metastases, and toxicity were evaluated. Lung metastases were treated with median PTV-encompassing single doses of 12.5Gy (range 3.0-33.0Gy) in a median number of 3 fractions (range 1-13). RESULTS: After a median follow-up time of 14.3 months, 2-year local control (LC) and overall survival (OS) were 81.2% and 54.4%, respectively. In multivariate analysis, OS was most significantly influenced by pretreatment performance status, maximum metastasis diameter, primary tumor histology, time interval between primary tumor diagnosis and SBRT treatment and number of metastases. For LC, independent prognostic factors were pretreatment performance status, biological effective dose (BED) at PTV isocenter (BEDISO) and single fraction (PTV-encompassing) dose in multivariate analysis. Radiation-induced pneumonitis grade 2 or higher was observed in 6.5% of patients. The only factor significantly influencing toxicity was BEDISO (p=0.006). CONCLUSION: SBRT for medically inoperable patients with pulmonary metastases achieved excellent local control and promising overall survival. Important prognostic factors were identified for selecting patients who might benefit most from this therapy approach.