Re-Irradiation of Progressive Brain Metastases After Whole Brain Radiotherapy: Outcome of Stereotactic Radiosurgery

Purpose: In our study, rates of and factors affecting survival obtained by frameless robotic stereotactic radiosurgery are investigated retrospectively in progressive brain metastases previously treated with total cranial radiotherapy.Materials and Methods: SRS was given as salvage therapy to 60 patients with brain metastases after WBRT. CyberKnife radiosurgical system (Accuray, Sunnyvale, CA) was used for SRS. Median 1800 (800- 2400) cGy dosage of SRS was used in 44 cases (68%) in one fraction, and in 21 cases (32%) in two fractions.Result: For 12 patients, progression occurred within the SRS field, and overall local control was 80%. Survival rate was 85% at sixth months, and 52% in 12th months (median 12.5 months). Significantly better survival rates were achieved in the patients who breast carcinoma was the primary tumor site. Survival rates significantly decreased if the systemic disease showed progression. A significant change in survival was not observed in different Recursive Partitioning Analysis (RPA) groups, however for Score Index for Radiosurgery (SIR) survival, there was a significant relation. In the multivariance analysis, younger age and smaller tumor size were significantly related with better survival.Conclusion: In the progressive brain metastases, patients with relatively limited life expectancy, SRS is a preferable alternative with 12 months median survival.