Introduction: Fractionated SRS may confer radiobiologic treatment advantages in the eradication of metastatic brain tumors. We compared the results of single and fractionated SRS for patients with metastatic tumors.
Methods: We reviewed all patients from our institution who were treated with SRS for intracranial metastases between January 2010 and January 2013. Collected data included diagnosis, tumor location, lesion volume, and SRS dose. Local control (LC) and volume changes after fractionated or single fraction SRS were compared using Wilcoxon rank sum and t-test.
Results: RESULTS: 152 patients with 299 lesions underwent SRS. 213 lesions were available for follow-up with serial MRI from 0.2 –31.8 months (8.6 ± 7.8 months) after SRS, with overall LC of 74.2%. 62 of these lesions had treatment volumes greater than 3 cc. Of these, 32 lesions underwent single session SRS and 30 were treated in 3 sessions. Median prescription doses for single and fractionated SRS were 20 Gy and 24 Gy, respectively. Tumor progression was observed during follow-up in 6/32 lesions treated with a single session, compared with progression in 1/30 lesion treated with 3 sessions
(p=0.02). Overall, lesion volume following fractionated SRS decreased by 68.6%, vs. a 61.4% decrease after single session SRS (p = 0.001).
Conclusions: In patients with metastatic tumors greater than 3 cc in volume, fractionated SRS yielded LC better than that obtained with single session SRS. In these patients, the volumetric decrease in tumor size was greater after multiple fraction than single fraction SRS. We recommend consideration of fractionated SRS for patients with metastatic tumors larger than 3 cc.
Patient Care: Large brain metastases are a treatment challenge. hypofractionated stereotactic radiosurgery provides improved disease control among patients with brain metastases.
Learning Objectives: By the conclusion of this session, participants should be able to 1) discuss the advantages of fractionated stereotactic radiosurgery 2)consider fractionated SRS for patients with large brain metastases