Gamma Knife and Treatment of Cases with Intracerebral Metastases

S.R. Ilyalov, A.V. Golanov, V.V. Kostyuchenko, I.N. Pronin, M.B. Dolgushin, V.A. Loshakov

(Burdenko Research Institute of Neurosurgery of the Russian Academy of Medical Science, Moscow)

A number of cases with metastatic lesions of the brain increases every year, exceeding a number of patients with primary CNS tumors. There is a constant search for optimum methods of treatment, promoting longer survival and better life quality in cases with brain metastases. Today many authors consider radiosurgery with applying a gamma-knife to be a method of choice in treatment of multiple intracerebral metastases.

The Goal of the Study. To develop an algorithm of diagnosis and radiosurgical treatment of cases, having cerebral metastases with a diameter of 3-3.5 cm.

Materials and Methods. There were 123 cases (52 males and 71 females) with brain metastases of extracranial tumors (27.04.2005 – 20.11.2006). Their mean age was 54 years (20-80 years). Most of them were at a mature or old age. Stereotaxic radiosurgery with applying a gamma-knife (SRSGK) was the first method of treatment of intracerebral metastases in 87 cases. It was preceded by open neurosurgical removal of intracerebral tumor in 26 patients, which was followed by local irradiation of its bed (3 cases) or irradiation of the whole brain (1 case). The rest cases were subjected to radio- and/or chemotherapy before SRSGK. Selection of patients for SRSGK, who had been treated with the above methods, was based on presence of further growth of a tumor or appearance of new metastatic foci, confirmed by MRI examination of the brain with enhancement. Karnofsy scale was used for estimation of a patient’s state at the moment of the first SRSGK. The majority of cases (77%) had a score of 70-90. Treatment was carried out with LEKSELL GAMMA KNIFE (model C; ELEKTA AB, Sweden). A total number of procedures was 153; 33 cases underwent 2 and more sessions of treatment. A total number of diagnosed metastases was 628. More than 10 metastases were revealed in 9 cases. The greatest number of metastases, irradiated during one session of SRSGK, was 32. Catamnesis was followed in 120 patients.

Results. A period of follow-up varied from 7 up to 703 days. Median survival was about 27 weeks. Satisfactory control of metastatic tumor growth was achieved in the majority of cases. Progression of intracerebral metastases, being the main cause of a fatal outcome, was watched only in 6 patients (5%). Thus, preliminary data have confirmed, that radiosurgery with applying LEKSELL GAMMA KNIFE is an effective and safe method of treatment of cerebral metastasis with a diameter of up to 3.5 cm. It ensures a high-level control of their growth and has no negative effect on life quality. It is important to combine radiosurgery of cerebral metastatic foci with therapy of the main disease and distant metastases in other organs.