Study of the dynamics of coagulation parameters in patients with brain metastases undergoing robotic radiosurgery with CyberKnife

Brain metastases (BM) are found in about 10% of patients at the time of diagnosis. In about 30-40% of cases a solitary lesion is found without other evidence of extracranial disease and in a controlled primary disease. Longitudinal prospective follow-up of 32 patients with other types of primary oncological diseases without cases of non-small cell lung cancer was performed. All patients are with BM verified by MRI at the Department of Diagnostic Imaging at University Hospital "St. George" - Plovdiv and treated with robotic stereotactic radiosurgery (SRS) with Cyber Knife in the Clinic of Radiotherapy at the same hospital between 2017-2020. Before therapy, at 1, 3, and 6 months after treatment, patients have follow-up monitoring of major coagulation parameters. Statistically significant changes were demonstrated: prolongation of aPTT and prothrombin index, decrease in TT between baseline and 6th month. Regardless of the observed dynamic changes in the coagulation parameters, they remain within the reference range. In the summary analysis, the results correlate with the therapeutic efficacy of SRS. Studying the dynamics of coagulation parameters and the MRT reports, could be a useful clinical and laboratory indicators for assessing the therapeutic response in SRS. Key words: brain metastasis, coagulation, robotic stereotactic radiosurgery, cyberknife