Post-Operative Stereotactic Radiosurgery for Resected Brain Metastases: A Comparison of Outcomes for Large Resection Cavities

Publication date: Available online 26 April 2017
Source:Practical Radiation Oncology
Author(s): Jim Zhong, Matthew J. Ferris, Jeffrey Switchenko, Robert H. Press, Zachary Buchwald, Jeffrey J. Olson, Bree R. Eaton, Walter J. Curran, Hui-Kuo G. Shu, Ian R. Crocker, Kirtesh R. Patel
PurposeAlthough historical trials have established the role of surgical resection followed by whole brain irradiation (WBRT) for brain metastases, WBRT has recently been shown to cause significant neurocognitive decline. Many practitioners have employed post-operative stereotactic radiosurgery (SRS) to tumor resection cavities to increase local control without causing significant neurocognitive sequelae. However, studies analyzing outcomes of large brain metastases treated with resection and post-operative SRS are lacking. Here we compare outcomes in patients with large brain metastases > 4 cm to those with smaller metastases ≤ 4 cm treated with surgical resection followed by SRS to the resection cavity.Methods and materialsConsecutive patients with brain metastases treated at our institution with surgical resection and post-operative SRS were retrospectively reviewed. Patients were stratified into ≤ 4 cm and > 4 cm cohorts based on pre-operative maximal tumor dimension. Cumulative incidence of local failure, radiation necrosis, and death were analyzed for the two cohorts using a competing-risk model, defined as the time from SRS treatment date to the measured event, death, or last follow-up.ResultsA total of 117 consecutive cases were identified. Of these patients, 90 (77%) had pre-operative tumors ≤ 4 cm, and 27 (23%) > 4 cm in greatest dimension. The only significant baseline difference between the two groups was a higher proportion of patients who underwent gross total resection in the ≤ 4 cm compared to the > 4 cm cohort, 76% vs. 48%, respectively (p<0.01). The 1-year rates of local failure, radiation necrosis, and overall survival for the ≤ 4 cm and > 4 cm cohorts were 12.3% and 16.0%, 26.9% and 28.4%, and 80.6% and 67.6%, respectively (all p>0.05). The rates of local failure and radiation necrosis were not statistically different on multivariable analysis based on tumor size.ConclusionsBrain metastases > 4 cm in largest dimension managed by resection and radiosurgery to the tumor cavity have promising local control rates without a significant increase in radiation necrosis on our retrospective review.



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