Clinical Outcomes of Large Brain Metastases Treated with Neurosurgical Resection and Intraoperative Cesium-131 Brachytherapy: Results of a Prospective Trial

Publication date: Available online 10 June 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Gabriella A. Wernicke, Cole B. Hirschfeld, Andrew W. Smith, Shoshana Taube, Menachem Z. Yondorf, Bhupesh Parashar, Lucy Nedialkova, Fridon Kulidzhanov, Samuel Trichter, Albert Sabbas, Rohan Ramakrishna, Susan Pannullo, Theodore H. Schwartz
BackgroundStudies on adjuvant stereotactic radiosurgery (SRS) to the cavity of resected brain metastases suggest that larger tumors (>2.0 cm) have higher rates of recurrence and radionecrosis (RN). This study assesses the impact of permanent low-dose ¹³¹Cs brachytherapy on local control and RN in patients treated for large brain metastases.MethodsAfter IRB approval, 42 patients with a total of 46 metastases >2.0 cm in preoperative diameter were accrued onto a prospective trial between 2010 and 2015. Patients underwent surgical resection with intra-operative placement of stranded ¹³¹Cs seeds as permanent volume implants in the resection cavity. The primary endpoint was local freedom from progression (FFP). Secondary endpoints included regional and distant FFP, overall survival (OS), and RN rate. Failures between 5 mm and 20 mm from the cavity, as well as dural-based failures, were considered regional. Separate analysis was performed for metastases > 3.0 cm.ResultsOf the 46 metastases, 18 were > 3.0 cm in diameter. The median follow-up period was 11.9 months (range, 0.6 – 51.9 months). Metastases had a median preoperative diameter of 3.0 cm (range, 2.0 – 6.8 cm). Local FFP was 100% for all tumor sizes. Regional recurrences were found in 3/46 (7%) lesions, yielding a 1-year region FFP of 89% (for tumors > 3.0 cm this was 80% (95% CI 54%, 100%). Distant recurrences were found in 19/46 (41%) patients yielding a 1-year distant FFP of 52%. The median OS was 15.1 months with a 1-year OS of 58%. Lesion size was not significantly associated with any endpoint in univariate or multivariate analysis. Radioresistant histology had worse survival (p=0.036). There were no cases of RN.ConclusionIntraoperative ¹³¹Cs brachytherapy is a promising and effective therapy for large brain metastases requiring neurosurgical intervention, which may offer improved local control and lower rates of RN compared with SRS to the resection cavity.

Teaser

Treating brain metastases ≥2 cm with radiation remains a challenge. Results from traditional techniques such as stereotactic radiosurgery are worse with larger lesions compared to smaller lesions. Here we present an alternative technique to treat large brain metastases using neurosurgical resection and intraoperative brachytherapy using a novel radioisotope, Cesium-131. Our study presents evidence that Cesium-131 results in high rates of local control, minimizes the risk of radionecrosis, and represents a safe and effective adjuvant therapy.


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