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.