Radiosurgery alone versus radiosurgery plus whole-brain irradiation for very few cerebral metastases from lung cancer

BACKGROUND: It is unclear whether patients with few cerebral metastases benefit from whole-brain irradiation added to radiosurgery. Since primary tumors disseminating to the brain show different behavior, this question should be answered separately for each tumor type. This study compared both treatments in patients with 1-3 cerebral metastases from lung cancer. METHODS: Ninety-eight patients receiving radiosurgery alone were retrospectively compared to 50 patients receiving radiosurgery plus whole-brain irradiation for local control, distant cerebral control and overall survival. Ten other characteristics were additionally considered including radiosurgery dose, age, gender, Eastern Cooperative Oncology Group (ECOG) performance score, histology, number of cerebral metastases, maximum diameter of all cerebral metastases, site of cerebral metastases, extra-cerebral metastases, and interval from lung cancer diagnosis to irradiation. RESULTS: The treatment approach had no significant impact on local control (p = 0.61). On multivariate analysis of local control, ECOG performance score was significant (risk ratio [RR]: 2.10; p < 0.001). The multivariate analysis of distant brain control revealed significant positive associations with radiosurgery plus whole-brain irradiation (RR: 4.67; p < 0.001) and one cerebral metastasis (RR: 2.62; p < 0.001). Treatment approach was not significantly associated with overall survival (p = 0.32). On multivariate analysis, significant associations with overall survival were found for maximum diameter of all cerebral metastases (RR: 1.81; p = 0.008), extra-cerebral metastases (RR: 2.98; p < 0.001), and interval from lung cancer diagnosis to irradiation (RR: 1.19; p < 0.001). CONCLUSION: Addition of whole-brain irradiation to radiosurgery significantly improved distant brain control in patients with few cerebral metastases from lung cancer. This improvement did not translate into better overall survival.