Survival Outcomes after Whole Brain Radiation Therapy and/or Stereotactic Radiosurgery for Cancer Patients with Metastatic Brain Tumors in Korea: A Systematic Review

Aim: To compare survival outcomes after whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), and WBRT plus SRS combination therapy in Korea, by performing a quantitative systematic review. Materials and Methods: We searched 10 electronic databases for reports on Korean patients treated with WBRT or SRS for brain metastases published prior to July 2010. Independent reviewers screened all articles and extracted the data. When a Kaplan-Meier survival curve was available, median survival time and standard errors were calculated. Summary estimates for the outcomes in each study were calculated using the inverse variance random-effects method. Results: Among a total of 2,761 studies, 20 studies with Korean patients (n=1,053) were identified. A combination of 12 studies (n=566) with WBRT outcomes showed a median survival time of 6.0 months (95% CI: 5.9-6.2), an overall survival rate of 5.6% (95% CI: 1-24), and a 6-month survival rate of 46.5% (95% CI: 37.2-56.1). For nine studies (n=412) on SRS, the median survival was 7.9 months (95% CI: 5.1-10.8), and the 6-month survival rate was 63.1% (95% CI: 49.8-74.8). In six studies (n=75) using WBRT plus SRS, the median survival was 10.7 months (95% CI: 4.7-16.6), and the overall and 6-month survival rates were 16.8% (95% CI: 6.2-38.2) and 85.7% (95% CI: 28.3-96.9), respectively. Conclusions: WBRT plus SRS showed better 1-year survival outcome than of WBRT alone for Korean patients with metastatic brain tumors. However, the results of this analysis have to be interpreted cautiously, because the risk factors of patients were not adjusted in the included studies.