Gamma Knife Radiosurgery For Brain Metastases In Eloquent Brain LocationDavid Mathieu, MD1, Dea Nicolas2, Borduas Martin2, Fortin David2, Kenny Brendan21Division of Neurosurgery, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke 2Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada Keywords: brain metastasis, cancer, radiosurgery, gamma knife, outcome
Brain metastases are the most frequent cerebral tumors. Tumors that are located in eloquent cerebral parenchyma can cause considerable morbidity and may represent a significant surgical challenge. Gamma knife radiosurgery (GKRS) is a recognized treatment modality for brain metastases.
This study was undertaken to assess the safety and efficacy of GKRS specifically for eloquent location brain metastases.
During the study period, 295 patients with 650 metastases had GKRS, of which 176 were located in eloquent areas (102 patients). For this subgroup, the median age was 59 years and women constituted 58.8% of the population. The median KPS was 80% (range 50-100%). Patients were in RPA class 1 in 22.5%, class 2 in 70.6% and class 3 in 6.9% of cases. Non small cell lung cancer (NSCLC) was the most common primary tumor (63.7% of metastases), followed by small cell lung (7.8%), breast (6.9%), colon (5.9%), melanoma (4.9%) and renal cell (3.9%).
The charts of patients with brain metastases treated by GKRS at the Centre Hospitalier Universitaire de Sherbrooke from August 2004 to April 2008 were reviewed. Planning images were assessed by an independent neurosurgeon to assess tumor location. Eloquent location was defined as primary motor, somatosensory, speech or visual cortex, basal ganglia, thalamus and brainstem. Survival, tumor response and complication rates were analyzed and compared to published surgical data.
The median dose to the tumor margin was 18 Gy (range, 14-24 Gy). The median survival after GKRS was 8 months. The RPA score was the most significant variable affecting survival (p<0.0001). Immediate control was achieved in 92.5% of tumors and 74.5% were still controlled at the last follow-up. The median time to progression was 16 months. Higher marginal dose (P=0.004), the absence of edema (P=0.04), as well as NSCLC histology positively affected the response rates. Steroids were stopped in 46% of patients. New neurological deficits occurred in 5.3% of patients and seizures in 5.3%. Radiologically, new edema occurred in 8% of treated metastasis and radiation necrosis in 1.3%.
This is a retrospective study.
Gamma knife radiosurgery is safe and effective for brain metastases located in eloquent areas.
D. Mathieu (), D. Nicolas (), B. Martin (), F. David (), K. Brendan ()