Stereotactic Body Radiotherapy Results for Pulmonary Oligometastases: A Two-Institution Collaborative Investigation.

AIM The current study investigated outcomes and prognostic factors of pulmonary oligometastases at two Institutions. PATIENTS AND METHODS SBRT (stereotactic body radiotherapy) as performed for pulmonary oligometastases from January 2004 to April 2014, and patients with a biologically effective dose (BED10) ≥ 75 Gy were registered in the study. Control of the primary tumor was not a criterion: we included both oligo-recurrence and sync-oligometastases. RESULTS A total of 34 patients were enrolled in the study. The median overall survival was 20 months (range=1-119 months) and the 2-year overall survival rate was 65.7% [95% confidence interval (CI)=48.3-83.1%]. The two-year local control rate was 79.1% (95% CI=62.4-95.8%). Stratified by oligo status, the 2-year overall survival rate of the oligo-recurrence group was 68.5% (95% CI=50.3-86.7%), while that of the group with sync-oligometastases was 50.0% (95% CI=1.0-99.0%). These rates were significantly different (p=0.037). No grade 5 early- or late-adverse events were recognized in the current study. CONCLUSION SBRT for pulmonary oligometastases achieved good results and there was no serious adverse event. The oligo-recurrence group, in particular, achieved fairly good results.