from
Neurosurgical Focus Steven D. Chang, M.D., Elizabeth Lee, R.N., N.P., Gordon T. Sakamoto, B.S., Nalani P. Brown, R.T.T., John R. Adler, Jr., M.D., Departments of Neurosurgery and Radiation Oncology, Stanford University School of Medicine, Stanford, California
Abstract
Object. Patients with multiple brain metastases are often treated primarily with fractionated whole-brain radiation therapy (WBRT). In previous reports the authors have shown that patients with four or fewer brain metastases can benefit from stereotactic radiosurgery in addition to fractionated WBRT. In this paper the authors review their experience using linear accelerator stereotactic radiosurgery to treat patients with multiple brain metastases.
Methods. Fifty-three patients with 149 brain metastases underwent stereotactic radiosurgery. The mean age of patients was 53.1 years (range 20-78 years). There were 23 men and 30 women. The primary tumor location was lung (27 patients), melanoma (10), breast (six), ovary (six), and other (four). All patients harbored at least two metastatic tumors treated with radiosurgery; 27 patients (51%) harbored two lesions, 17 (32%) three lesions, eight (15%) four lesions, and one patient (2%) harbored five lesions. The mean radiation dose administered was 19.6 Gy (range 14-30 Gy), and the mean secondary collimator size was 15.7 mm (range 7.5-40 mm). One hundred thirty-two (89%) of the 149 treated tumors were available for review on magnetic resonance (MR) imaging at 3 months posttreatment. Fifty-two percent were smaller in size, 31% were stable, 9% had increased in size, and 8% had disappeared. New metastatic tumors appeared in 12 (23%) of the 53 patients on MR imaging within 6 months posttreatment. Radiation-induced necrosis occurred at the site of eight (5.4%) of the 149 tumors at 6 months. Seven tumors (4.7%) subsequently required surgical resection for either tumor progression (four cases) or worsening edema from radiation-induced necrosis (three cases). Median actuarial survival was 9.6 months.
Conclusions. Stereotactic radiosurgery can be used to treat patients with up to four brain metastases with a 91% rate of either decrease or stabilization in tumor size and a low rate of radiation-induced necrosis. In the authors' study only a small number of patients subsequently required surgical resection of a treated lesion.
Introduction
Multiple brain metastases commonly occur in patients with cancer, and the American Cancer Society estimates that 170,000 cancer patients develop cerebral metastases each year in the United States.
[18] The prognosis in this patient population is poor; the mean survival rate is approximately 4 to 6 months, even after WBRT.
[4,7,26] Stereotactic radiosurgery has emerged as a treatment in patients with brain metastasis either alone or in combination with WBRT. Because most patients with metastases eventually succumb to their underlying malignancy, the primary benefits of radiosurgery are palliation of symptoms and some modest prolongation of survival length. Radiosurgical treatment of patients with either one or two brain metastases has been shown to result in good local control and a median patient survival (range 6-10 months)
[2,6,8,10-12,14,15,22,24] comparable to that obtained after surgical resection and WBRT (range 4-13 months).
[9,23] Furthermore, stereotactic radiosurgery combined with WBRT in patients with two to four metastases may be superior to WBRT alone in the control of brain disease.
[13] In this report, we review our experience at Stanford University over the last 5 years in the treatment of patients with multiple (two to four) brain metastases in whom LINAC stereotactic radiosurgery has been performed.
