Gamma knife surgery for brain metastases in patients harboring four or more lesions: survival and prognostic factors

Abstract

Object. This study was performed to evaluate the role of gamma knife surgery (GKS) in patients with a large number (four or more) of metastatic brain lesions. Methods. The authors retrospectively reviewed the outcome in 130 patients who underwent GKS for metastatic lesions. Eighty-four patients presented with one to three lesions (Group A) and 46 presented with four or more lesions (Group B). The overall median survival time after GKS was 35 weeks. The median survival time in Group A (48 weeks) was significantly longer (p = 0.005) than the survival time in Group B (26 weeks). The recursive partitioning analysis (RPA) class was the only significant prognostic factor identified in multivariate analysis. The median survival for patients in RPA Classes I, II, and III was 72, 48, and 19 weeks, respectively, in Group A and 36 and 13 weeks for Classes II and III in Group B. The number of lesions, tumor volume, whole brain radiotherapy, primary tumor site, age, and sex did not affect survival significantly. Conclusions. It is suggested that GKS provides an increase in survival time even in patients with a large number (four or more) of metastatic lesions. Concerning the selection of patients for GKS, RPA class should be considered as the most important factor and multiplicity of the lesions alone should not be a reason for withholding GKS.

Radiosurgery for Brain Metastases From Unknown Primary Cancers

“…The median survival of 11.9 months in the current series with radiosurgery compares favorably with historical surgical series. The efficacy of radiosurgery for patients with a brain metastasis is well established (18)(19)(20)(21)(22)(23)(24). Local tumor control after radiosurgery is not dependent on the histology of the tumor.…”

Radiosurgery for metastatic brain tumors

“…[26][27][28][29][30][31][35][36][37][38][39][40][41] These reports suggest that SRS is more effective than WBRT and that it is comparable to or superior to surgery. [26][27][28][29][30][31][32][35][36][37][38][39][40][41][42][43] SRS as the sole initial management or as a boost before or after WBRT has emerged as a widely practiced treatment modality for brain metastases. The goal of SRS without WBRT is to achieve brain control without the possible long-term neurotoxic or cognitive side effects of WBRT.…”

“…[26][27][28][29][30][31]33,[35][36][37][38][39][40][41][58][59][60] In addition to systemic disease status, other factors may contribute to the discrepancy between the high rate of local tumor control and the lower rates of survival. Other retrospective studies reported median survivals to range from 8 to 15 months.…”

“…19,20 On the other hand, we must understand the differences in SRS devices between GK and LINIAC, including the radiation beams, images for treatment planning, planning software, irradiation methods, set-up margin, frame fi xation, practitioners, the availability of fractionation, and limitations in lesion number and size to be irradiated in a single session, as shown in Table 1. 12,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] A Radiation Therapy Oncology Group (RTOG) study (RTOG 9005) reported better local brain tumor control for GK than for LINIAC. 9,17 However, that study was not randomized, and LINIAC technology has improved recently.…”

Current therapeutic approaches in patients with brain metastases

“…This survival difference did not reach statistical significance. Nam et al [19] retrospectively compared a cohort of patients with one to three metastases to a cohort with four or more metastases. The group with fewer brain metastases had a significantly longer median survival; however, on multivariate analysis, RPA class was the only significant prognostic factor identified.…”