Gamma-knife Radiosurgery to 4 or More Brain Metastases in Patients Without Prior Intracranial Radiation or Surgery

Abstract

Purpose/Objective(s)Data on stereotactic radiosurgery (SRS) for 4 or more metastases is limited. Existing studies, all retrospective, are complicated by significant proportions of patients with prior whole brain radiation therapy (WBRT) or concurrent WBRT with SRS. Furthermore, published results disagree about the impact of tumor volume on overall survival.Materials/MethodsThis is a retrospective review of 435 patients who underwent SRS using gamma-knife (GK) for intracranial metastases between 2006 and 2010. We identified 38 patients with no prior history of intracranial radiation or surgery who received GK as sole treatment to 4 or more metastases in a single session. A subset of 28 cases with follow-up imaging was analyzed for patterns of intracranial progression. Survival was calculated via the Kaplan-Meier method. The association between outcomes and patient or disease characteristics was examined by univariate (log-rank test) and multivariate (Cox proportional hazards model) analyses.ResultsEighteen men (47%) and 20 women (53%) underwent GK at a median age of 66 years. Common primary tumors were non-small cell lung (45%), melanoma (37%), and breast (8%). Extracranial disease was classified as progressive (37%), stable (13%), newly diagnosed (45%) or none (5%). Cases were identified as RPA class II (94%) or III (6%). Patients harbored a median 5 tumors (range, 4-12) with a median total tumor volume of 1.2 mL (range, 0.11-15.7). A median dose of 21 Gy (range, 15-21) was prescribed to the 50% isodose line. At the time of analysis, 30 patients (79%) had died. Median follow-up for the 8 living cases was 17 months and for the entire cohort was 6.8 months. Patients survived a median 6.7 months from GK. Local treatment failure occurred in 1 case (4%) and distant failure in 22 cases (79%) at a median 4.6 months from GK. On multivariate analysis, total tumor volume > 3 mL was significantly associated with both distant failure and worsened overall survival (p = 0.042 and 0.040, respectively). Male gender was significantly associated with distant failure and approached significance for worsened survival (p = 0.043 and 0.079, respectively). Primary tumor type was controlled in both analyses. Nineteen patients (50%) underwent some form of salvage radiation therapy. WBRT was given to 14 patients (37%) at a median 10.3 months from GK. Seven patients (18%) received repeat GK. Treatment was complicated by symptomatic radionecrosis in 2 patients, seizures in 1 patient, and development of leptomeningeal disease on imaging in 5 patients.ConclusionGK as sole treatment for 4 or more simultaneous metastases spares most patients WBRT and delays it for others. Our data support the view that increased total tumor volume is significantly associated with worsened overall survival. Purpose/Objective(s)Data on stereotactic radiosurgery (SRS) for 4 or more metastases is limited. Existing studies, all retrospective, are complicated by significant proportions of patients with prior whole brain radiation therapy (WBRT) or concurrent WBRT with SRS. Furthermore, published results disagree about the impact of tumor volume on overall survival. Data on stereotactic radiosurgery (SRS) for 4 or more metastases is limited. Existing studies, all retrospective, are complicated by significant proportions of patients with prior whole brain radiation therapy (WBRT) or concurrent WBRT with SRS. Furthermore, published results disagree about the impact of tumor volume on overall survival. Materials/MethodsThis is a retrospective review of 435 patients who underwent SRS using gamma-knife (GK) for intracranial metastases between 2006 and 2010. We identified 38 patients with no prior history of intracranial radiation or surgery who received GK as sole treatment to 4 or more metastases in a single session. A subset of 28 cases with follow-up imaging was analyzed for patterns of intracranial progression. Survival was calculated via the Kaplan-Meier method. The association between outcomes and patient or disease characteristics was examined by univariate (log-rank test) and multivariate (Cox proportional hazards model) analyses. This is a retrospective review of 435 patients who underwent SRS using gamma-knife (GK) for intracranial metastases between 2006 and 2010. We identified 38 patients with no prior history of intracranial radiation or surgery who received GK as sole treatment to 4 or more metastases in a single session. A subset of 28 cases with follow-up imaging was analyzed for patterns of intracranial progression. Survival was calculated via the Kaplan-Meier method. The association between outcomes and patient or disease characteristics was examined by univariate (log-rank test) and multivariate (Cox proportional hazards model) analyses. ResultsEighteen men (47%) and 20 women (53%) underwent GK at a median age of 66 years. Common primary tumors were non-small cell lung (45%), melanoma (37%), and breast (8%). Extracranial disease was classified as progressive (37%), stable (13%), newly diagnosed (45%) or none (5%). Cases were identified as RPA class II (94%) or III (6%). Patients harbored a median 5 tumors (range, 4-12) with a median total tumor volume of 1.2 mL (range, 0.11-15.7). A median dose of 21 Gy (range, 15-21) was prescribed to the 50% isodose line. At the time of analysis, 30 patients (79%) had died. Median follow-up for the 8 living cases was 17 months and for the entire cohort was 6.8 months. Patients survived a median 6.7 months from GK. Local treatment failure occurred in 1 case (4%) and distant failure in 22 cases (79%) at a median 4.6 months from GK. On multivariate analysis, total tumor volume > 3 mL was significantly associated with both distant failure and worsened overall survival (p = 0.042 and 0.040, respectively). Male gender was significantly associated with distant failure and approached significance for worsened survival (p = 0.043 and 0.079, respectively). Primary tumor type was controlled in both analyses. Nineteen patients (50%) underwent some form of salvage radiation therapy. WBRT was given to 14 patients (37%) at a median 10.3 months from GK. Seven patients (18%) received repeat GK. Treatment was complicated by symptomatic radionecrosis in 2 patients, seizures in 1 patient, and development of leptomeningeal disease on imaging in 5 patients. Eighteen men (47%) and 20 women (53%) underwent GK at a median age of 66 years. Common primary tumors were non-small cell lung (45%), melanoma (37%), and breast (8%). Extracranial disease was classified as progressive (37%), stable (13%), newly diagnosed (45%) or none (5%). Cases were identified as RPA class II (94%) or III (6%). Patients harbored a median 5 tumors (range, 4-12) with a median total tumor volume of 1.2 mL (range, 0.11-15.7). A median dose of 21 Gy (range, 15-21) was prescribed to the 50% isodose line. At the time of analysis, 30 patients (79%) had died. Median follow-up for the 8 living cases was 17 months and for the entire cohort was 6.8 months. Patients survived a median 6.7 months from GK. Local treatment failure occurred in 1 case (4%) and distant failure in 22 cases (79%) at a median 4.6 months from GK. On multivariate analysis, total tumor volume > 3 mL was significantly associated with both distant failure and worsened overall survival (p = 0.042 and 0.040, respectively). Male gender was significantly associated with distant failure and approached significance for worsened survival (p = 0.043 and 0.079, respectively). Primary tumor type was controlled in both analyses. Nineteen patients (50%) underwent some form of salvage radiation therapy. WBRT was given to 14 patients (37%) at a median 10.3 months from GK. Seven patients (18%) received repeat GK. Treatment was complicated by symptomatic radionecrosis in 2 patients, seizures in 1 patient, and development of leptomeningeal disease on imaging in 5 patients. ConclusionGK as sole treatment for 4 or more simultaneous metastases spares most patients WBRT and delays it for others. Our data support the view that increased total tumor volume is significantly associated with worsened overall survival. GK as sole treatment for 4 or more simultaneous metastases spares most patients WBRT and delays it for others. Our data support the view that increased total tumor volume is significantly associated with worsened overall survival.