A matched-pair study comparing whole-brain irradiation alone to radiosurgery or fractionated stereotactic radiotherapy alone in patients irradiated for up to three brain metastases

Background: This matched-pair study was initiated to validate the results of a retrospective study of 186 patients published in 2007 that compared whole-brain irradiation (WBI) alone and radiosurgery (RS) alone for up to three brain metastases. Methods: One-hundred-fifty-two patients receiving WBI alone for up to three brain metastases were matched with 152 patients treated with RS of fractionated stereotactic radiotherapy (FSRT) alone 1:1 for each of eight factors (age, gender, Eastern Oncology Cooperative Group (ECOG)-performance score, nature of tumor, brain metastases number, extra-cerebral spread, period from cancer detection to irradiation of brain metastases, and recursive partitioning analysis (RPA)-class. Groups were analyzed regarding intracerebral control (IC) and overall survival (OS). Results: On univariate analysis of IC, type of irradiation did not significantly affect outcomes (p=0.84). On Cox regression, brain metastases number (p<0.001), nature of tumor (p<0.001) and period from cancer detection to irradiation of brain metastases (p=0.013) were significantly associated with IC. On univariate analysis of OS, type of irradiation showed no significant association with outcomes (p=0.63). On multivariate analyses, OS was significantly associated with ECOG performance score (p=0.011), nature of tumor (p=0.035), brain metastases number (p=0.048), extra-cerebral spread (p=0.002) and RPA-class (p<0.001). Conclusion: In this matched-pair study, RS/FSRT alone was not superior to WBI alone regarding IC and OS. These results can be considered a revision of the findings from our retrospective previous study without matched-pair design, where RS alone resulted in significantly better IC than WBI alone on multivariate analysis.