Radiosurgery to the surgical cavity as adjuvant therapy for resected brain metastasis.

Background: The standard treatment of resected brain metastasis is whole-brain radiotherapy (WBRT). To avoid the potential toxicity of WBRT and to improve local control, we have used radiosurgery alone to the surgical cavity.

Objective: To demonstrate the rates of local control, new intracranial metastasis, and overall survival using this treatment scheme without WBRT.

Methods: Eighty-five consecutive patients with brain metastasis were treated with surgical resection of at least 1 lesion followed by radiosurgery alone to the surgical cavity and any unresected lesions from August 2000 to March 2011. Sixty-eight percent had gross total resections. After surgery, radiosurgery was delivered to the surgical cavity with a 2- to 3-mm margin. The median marginal radiosurgery dose was 16 Gy, and median target volume was 13.96 cm. Follow-up imaging and clinical examination were obtained every 2 to 3 months.

Results: Median follow-up time was 11.2 months. Overall local control was 81.2%. The 6-month, 1-year, and 2-year rates of local control were 88.7%, 81.4%, and 75.7%, respectively. Forty-seven patients (55%) developed new intracranial metastases at a median time of 5.6 months. For the entire population, the rate of new metastases was 32.1%, 58.1%, and 62.9% at 6 months, 1 year, and 2 years, respectively. Median overall survival time was 12.1 months. From initial treatment until death or last follow-up, only 30 patients (35%) received WBRT as salvage treatment.

Conclusion: Radiosurgery to the surgical cavity without WBRT achieved excellent local control of resected brain metastasis. Close imaging follow-up allows early intervention for any new metastasis.