Acute intratumoral hemorrhage occurring during a radiosurgical session for a metastatic lesion, or in the immediate post-treatment period, is believed to be extremely rare. It is not yet clearly understood the potential risk of hemorrhage related to SRS in patients with metastatic brain tumors. 

     The aim of this study is to provide the incidence and the clinical detail of this complication, and to explore possible predictive factors.

     From April 2009 to March 2011, 426 medical records of patients with diagnosis of brain metastasis, who received gamma knife surgery (GKS) were analyzed. Patients’ age ranged from 29 to 93 years old with a median age of 66.The number of radiosurgical interventions needed for those was 624 and the number of lesions treated was 2530.

      The most common primary tumor type was lung cancer (260 cases), followed by breast cancer (55 cases) and colorectal cancer (40 case). 11 patients with renal cell carcinoma were also included in this series.

     We eventually experienced three cases of fatal intratumoral hemorrhage taking place while radiation or immediate after the radiation. Accordingly, the frequency of this type of complication was estimated as 0.7% per patient, 0.5% per intervention and 0.12% per lesion. Metastases from renal cell carcinoma, evidence of pre-radiosurgical peritumoral hemorrhage, anti-coagulant therapy and anti-angiogenic therapy seemed possible predictive factors for intratumoral hemorrhage in the present series.

     This was a retrospective evaluation.

     Life-threatening intratumoral hemorrhage could be one of the possible adverse reactions of radiosurgical treatment for metastatic brain tumors. 

     This hemorrhagic complication might be extremely rare but should be well recognized.