Predicting the risk of subsequent distant brain metastases after stereotactic radiosurgery or fractionated stereotactic radiotherapy in elderly patients

Background/Aim: Treatment for elderly patients with few brain metastases is controversial. A score was generated to predict distant brain metastases (DBMs) after stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT). Patients and Methods: Ten characteristics were retrospectively analyzed for freedom from new DBMs in 104 elderly patients receiving SRS or FSRT alone for 1-3 brain metastases. Characteristics that were significant or showed a trend on multivariate analysis were used for the score. Results: On multivariate analysis, favorable histology (p=0.026) and single brain metastasis (p=0.006) showed significant associations with freedom from DBMs. A trend was found for supra-tentorial location only (p=0.065). Three groups were designed, 10-14, 16-20 and 21-25 points, with 6-month rates of freedom from DBMs of 10%, 54% and 95%, respectively (p<0.0001). Positive predictive values to predict DBMs and freedom from DBMs at 6 months were 91% and 94%. Conclusion: This new score provided high accuracy in predicting DBMs and freedom from DBMs.