ИСТИНА

Brain metastases (BM) are the most frequent tumors of the central nervous system. Nowadays stereotactic radiosurgery (SRS) is treatment of choice for BM in many situations. Local recurrences after radiosurgery seriously complicate the course of cancer diseases and worse the prognosis of life duration, neurological status and quality of life in patients with BM. Currently, there are no standards of treatment for recurrent BM. The purpose of the study to evaluate the efficacy and safety of repeated radiosurgical (rRS) procedures for local relapses (LR) in patients with brain metastases after prior stereotaxic surgery. Materials and methods. An analysis of the re-irradiation local treatment of 59 patients were carried out. There were 110 lesions of LR detected after the previously performed SRS with Gamma Knife (GK). Primary cancer was: non-small cell lung cancer in 10 (17%), breast cancer in 29 (49%), melanoma in 13 (22%), renal cell carcinoma in 5 (8.5%) and colorectal cancer in 2 (3.5%) patients. All patients underwent repeated radiosurgery with median marginal dose 22 Gy (15 to 24 Gy). Results. The local control of repeated irradiated BM for the 6- and 12-month periods was 95.5% and 83.9%, respectively. Statistically significant prediction factors for lower risk of LR after rRS were: the volume of the lesion ≤1 cc (p=0.0241) and dose >20Gy/D99% (p=0,031), according to multifactorial analysis. The frequency of local radionecrosis after repeated radiosurgery was higher than after first SRS: 28.2% vs. 13.3%. The volume of LR ≤1 cc was a significant predictor of lower risk of post-radiation edema (p=0.01) and radio necrosis (p=0.0224) according to multifactorial analysis. Conclusions: The SRS of LR is an effective treatment for controlling tumor growth of repeated irradiated BM with acceptable post-radiation toxicity. Repeated stereotactic radiosurgery (SRS) of local recurrences (LR) of GM is designed to improve treatment outcomes, maintain quality of life and prolong it in patients with brain metastases who relapse after prior radiosurgery. The volume of the LR focus can change the treatment tactics: it is possible that with a metastasis recurrence size of more than 1 cm3, it is preferable to use surgical treatment or stereotactic radiation in the hypofractionation mode, which needs to be confirmed in further studies