Treatment options for patients with brain metastasis include tumor resection, whole-brain radiation therapy and radiosurgery. Single treatment is not useful in cases of multiple tumors, of which at least one is a cystic tumor.

     The purpose of this study was to asses the role of stereotactic drainage and gamma knife radiosurgery in the treatment of cystic brain metastasis.

     Study inclusive criteria were: no prior whole-brain radiation therapy or surgical resection, a maximum number of five lesions on pre-op MRI scan, at least one cystic lesion, KPS > 70, histological diagnosis of malignant tumor. Between February 2001 and December 2007, 41 patients were included in this study (24 male, 17 female; mean age 64 yrs; range 34-79 yrs). The primary cancer in most patients was lung (NSCLC; 27 pts, 66%). A single metastasis was present in 13 pts (43.3%). The total number of tumors was 102, of those 34 were cystic. 16 patients (39 %) were in RPA class I, 20 (61%) were in class II.

     Gamma Knife, The mean prescription dose to the tumor margin was 19.5 Gy (range 12-25 Gy).

     Before drainage the mean tumor volume was 21.8 ml (3.8-68 ml); after drainage and before Gamma Knife the mean tumor volume was 10.1 ml (1.2-32 ml). The mean prescription dose to the tumor margin was 19.5 Gy (range 12-25 Gy). Overall median survival was 14 months. One and two year survival rates were 54% (95% C.I. 45.3-64.1%) and 33% (95% C.I. 23.1-45.3%). Local tumor control was achieved in 94.5%.

     This is a retrospective study.

     This study supports the use of a multiple stereotactic approach in cases of multiple and cystic brain metastasis.